My work is to create an excel file, which will contain 3 fields: Address, Latitude and longitude.The user will upload an Address in an excel file and after reading the addresses from an excel file, I have to retrieve Latitude and longitude, using Bing MAP API and build another excel file, which can contain Addresses beside the Latitude and longitude of that address and download the new excel file to the user's end.

Create a MVC Application and add EPPLUS from NuGet package manager to your solution.

Now, Add the code to your .cshtml page.

<h2>Upload File</h2> 
 
sing (Html.BeginForm("Upload", "Home", null, FormMethod.Post, new { enctype = "multipart/form-data" })) 
  { 
      @Html.AntiForgeryToken() 
      @Html.ValidationSummary() 
 
      <div class="form-group"> 
          <input type="file" id="dataFile" name="upload" /> 
      </div> 
 
      <div class="form-group"> 
          <input type="submit" value="Upload" class="btn btn-default" /> 
      </div> 
 
       
  } 

And then, add the code, mentioned below to your controller.

[HttpPost] 
        public ActionResult Upload(HttpPostedFileBase upload) 
        { 
            if (ModelState.IsValid) 
            { 
                if (Path.GetExtension(upload.FileName) == ".xlsx") 
                { 
                    ExcelPackage package = new ExcelPackage(upload.InputStream); 
            //From This part we will read excel file 
                    DataTable dt = ExcelPackageExtensions.ToDataTable(package); 
 
 
                    DataTable dtExcel = new DataTable(); 
                    dtExcel.Columns.Add("Address", typeof(String)); 
                    dtExcel.Columns.Add("LAT", typeof(Double)); 
                    dtExcel.Columns.Add("LONG", typeof(Double)); 
 
                    List<Coordinates> lstCor = new List<Coordinates>(); 
                    for (int i = 0; i < dt.Rows.Count; i++) 
                    { 
                        //Fill the new data Table to generate new excel file 
                    } 
            //This method will generate new excel and download the same 
                    generateExcel(dtExcel);                  
                } 
            } 
            return View(); 
        } 

“ExcelPackageExtensions.ToDataTable(package)” for this create a new class with the name ExcelPackageExtensions and create a static method with the name “ToDataTable()”. The code is mentioned below.

public static class ExcelPackageExtensions 
    { 
        public static DataTable ToDataTable(this ExcelPackage package) 
        { 
            ExcelWorksheet workSheet = package.Workbook.Worksheets.First(); 
            DataTable table = new DataTable(); 
            foreach (var firstRowCell in workSheet.Cells[1, 1, 1, workSheet.Dimension.End.Column]) 
            { 
                table.Columns.Add(firstRowCell.Text); 
            } 
 
            for (var rowNumber = 2; rowNumber <= workSheet.Dimension.End.Row; rowNumber++) 
            { 
                var row = workSheet.Cells[rowNumber, 1, rowNumber, workSheet.Dimension.End.Column]; 
                var newRow = table.NewRow(); 
                foreach (var cell in row) 
                { 
                    newRow[cell.Start.Column - 1] = cell.Text; 
                } 
                table.Rows.Add(newRow); 
            } 
            return table; 
        } 
    } 

Now, add the code part to generate and download an Excel file.
[NonAction] 
        public void generateExcel(DataTable Dtvalue) 
        { 
            string excelpath = ""; 
            excelpath = @"C:\Excels\abc.xlsx";//Server.MapPath("~/UploadExcel/" + DateTime.UtcNow.Date.ToString() + ".xlsx"); 
            FileInfo finame = new FileInfo(excelpath); 
            if (System.IO.File.Exists(excelpath)) 
            { 
                System.IO.File.Delete(excelpath); 
            } 
            if (!System.IO.File.Exists(excelpath)) 
            { 
                ExcelPackage excel = new ExcelPackage(finame); 
                var sheetcreate = excel.Workbook.Worksheets.Add(DateTime.UtcNow.Date.ToString()); 
                if (Dtvalue.Rows.Count > 0) 
                { 
                    for (int i = 0; i < Dtvalue.Rows.Count; ) 
                    { 
                        sheetcreate.Cells[i + 1, 1].Value = Dtvalue.Rows[i][0].ToString(); 
                        sheetcreate.Cells[i + 1, 2].Value = Dtvalue.Rows[i][1].ToString(); 
                        sheetcreate.Cells[i + 1, 3].Value = Dtvalue.Rows[i][2].ToString(); 
                        i++; 
                    } 
                } 
                //sheetcreate.Cells[1, 1, 1, 25].Style.Font.Bold = true; 
                //excel.Save(); 
 
                var workSheet = excel.Workbook.Worksheets.Add("Sheet1"); 
                //workSheet.Cells[1, 1].LoadFromCollection(data, true); 
                using (var memoryStream = new MemoryStream()) 
                { 
                    Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"; 
                    Response.AddHeader("content-disposition", "attachment;  filename=Contact.xlsx"); 
                    excel.SaveAs(memoryStream); 
                    memoryStream.WriteTo(Response.OutputStream); 
                    Response.Flush(); 
                    Response.End(); 
                } 
            } 
 
        } 

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At the past few years, we have discussed about common error that you can find when published .NET Core, the most common error is 502.5 – process failure error.

Startup errors with ASP.NET Core don’t provide much information either, at least not in a production environment. Here are 7 tips for understanding and fixing those errors.

1. There are two types of startup errors.

There are unhandled exceptions originating outside of the Startup class, and exceptions from inside of Startup. These two error types can produce different behavior and may require different troubleshooting techniques.

2. ASP.NET Core will handle exceptions from inside the Startup class.

If code in the ConfigureServices or Configure methods throw an exception, the framework will catch the exception and continue execution.

Although the process continues to run after the exception, every incoming request will generate a 500 response with the message “An error occurred while starting the application”.

Two additional pieces of information about this behavior:

- If you want the process to fail in this scenario, call CaptureStartupErrors on the web host builder and pass the value false.

- In a production environment, the “error occurred” message is all the information you’ll see in a web browser. The framework follows the practice of not giving away error details in a response because error details might give an attacker too much information. You can change the environment setting using the environment variable ASPNETCORE_ENVIRONMENT, but see the next two tips first. You don’t have to change the entire environment to see more error details.

3. Set detailedErrors in code to see a stack trace.

The following bit of code allows for detailed error message, even in production, so use with caution.

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
           .CaptureStartupErrors(true) // the default
           .UseSetting("detailedErrors", "true")
           .UseStartup<Startup>();

4. Alternatively, set the ASPNETCORE_DETAILEDERRORS environment variable.

Set the value to true and you’ll also see a stack trace, even in production, so use with caution.

5. Unhandled exceptions outside of the Startup class will kill the process.

Perhaps you have code inside of Program.cs to run schema migrations or perform other initialization tasks which fail, or perhaps the application cannot bind to the desired ports. If you are running behind IIS, this is the scenario where you’ll see a generic 502.5 Process Failure error message.

These types of errors can be a bit more difficult to track down, but the following two tips should help.

6. For IIS, turn on standard output logging in web.config.

If you are carefully logging using other tools, you might be able to capture output there, too, but if all else fails, ASP.NET will write exception information to stdout by default. By turning the log flag to true, and creating the output directory, you’ll have a file with exception information and a stack trace inside to help track down the problem.

The following shows the web.config file created by dotnet publish and is typically the config file in use when hosting .NET Core in IIS. The attribute to change is the stdoutLogEnabled flag.

<system.webServer>
  <handlers>
    <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModule" resourceType="Unspecified" />

  </handlers>
  <aspNetCore processPath="dotnet" arguments=".\codes.dll"
              stdoutLogEnabled="true" stdoutLogFile=".\logs\stdout" />
</system.webServer>

Important: Make sure to create the logging output directory.

Important: Make sure to turn logging off after troubleshooting is complete.

7. Use the dotnet CLI to run the application on your server.

If you have access to the server, it is sometimes easier to go directly to the server and use dotnet to witness the exception in real time. There’s no need to turn on logging or set and unset environment variables.

Summary

Debugging startup errors in ASP.NET Core is a simple case of finding the exception. In many cases, #7 is the simplest approach that doesn’t require code or environment changes. FYI, we also have support latest ASP.NET Core on our hosting environment. Feel free to visit our site at https://www.hostforlife.eu.

In this article, we will see how to upload a file into the database using the Angular 7 app in an ASP.NET project. Let us create a new project in Visual Studio 2017. We are using ASP.NET Core 2 and Angular 7 for this project.

Prerequisites:

• Node JS must be installed
• Angular CLI must be installed
• Basic knowledge of Angular

Let’s get started.

Create a new project and name it as FileUploadInAngular7

Select a new project with Angular in .NET Core and uncheck the configure HTTPS

Your project will be created. Left click on ClientApp and open it in file explorer

Type cmd as shown in the picture.

Type npm install in the cmd

Now it will take time and all the node_modules will be installed in the project.

Create a Web API controller as UploadController.

Add the following code in it.

using System.IO;
using System.Net.Http.Headers;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
namespace FileUploadInAngular7.Controllers
{
    [Produces("application/json")]
    [Route("api/[controller]")]
    public class UploadController : Controller
    {
        private IHostingEnvironment _hostingEnvironment;
        public UploadController(IHostingEnvironment hostingEnvironment)
        {
            _hostingEnvironment = hostingEnvironment;
        }
        [HttpPost, DisableRequestSizeLimit]
        public ActionResult UploadFile()
        {
            try
            {
                var file = Request.Form.Files[0];
                string folderName = "Upload";
                string webRootPath = _hostingEnvironment.WebRootPath;
                string newPath = Path.Combine(webRootPath, folderName);
                if (!Directory.Exists(newPath))
                {
                    Directory.CreateDirectory(newPath);
                }
                if (file.Length > 0)
                {
                    string fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
                    string fullPath = Path.Combine(newPath, fileName);
                    using (var stream = new FileStream(fullPath, FileMode.Create))
                    {
                        file.CopyTo(stream);
                    }
                }
                return Json("Upload Successful.");
            }
            catch (System.Exception ex)
            {
                return Json("Upload Failed: " + ex.Message);
            }
        }
    }
}

Navigate to the following path and open both the files.

In home.component.html write the following code.

<h1>File Upload Using Angular 7 and ASP.NET Core Web API</h1>
<input #file type="file" multiple (change)="upload(file.files)" />
<br />
<span style="font-weight:bold;color:green;" *ngIf="progress > 0 && progress < 100">
  {{progress}}%
</span>
<span style="font-weight:bold;color:green;" *ngIf="message">
  {{message}}
</span>

In home.component.ts file write the following code in it.

import { Component, OnInit } from '@angular/core';
import { HttpClient, HttpRequest, HttpEventType, HttpResponse } from '@angular/common/http';
@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
})
export class HomeComponent {
  public progress: number;
  public message: string;
  constructor(private http: HttpClient) { }
  upload(files) {
    if (files.length === 0)
      return;
    const formData = new FormData();
    for (let file of files)
      formData.append(file.name, file);
    const uploadReq = new HttpRequest('POST', `api/upload`, formData, {
      reportProgress: true,
    });
    this.http.request(uploadReq).subscribe(event => {
      if (event.type === HttpEventType.UploadProgress)
        this.progress = Math.round(100 * event.loaded / event.total);
      else if (event.type === HttpEventType.Response)
        this.message = event.body.toString();
    });
  }
}

Run the project and you will see the following output.

Once you finish developing an ASP.NET Core web application, you need to deploy it on a server so that end users can start using it. When it comes to deployment to IIS, ASP.NET Core offers two hosting models namely InProcess and OutOfProcess. In this article you learn about these hosting models and how to configure them.

When you deploy your web application to IIS, various requests to the application are handled by what is known as ASP.NET Core Module. Under default settings the hosting model for your application is InProcess. This means ASP.NET Core Module forwards the requests to IIS HTTP Server (IISHttpServer). The IIS HTTP Server is a server that runs in-process with IIS. This results in great performance as compared to Out Of Process model. In-process models bypasses built-in Kestrel web server of ASP.NET Core.

If you decide to use Out-Of-Process hosting model then IIS HTTP Server won't be used. Instead Kestrel web server is used to process your requests. So, ASP.NET Core Module forwards your requests to Kestrel web server. This communication is out-of-process communication and is therefore slower than the in-process model.

Now that you have some basic idea about the in-process and out-of-process hosting models let's see how to configure them.

In order to understand the hosting models discussed in this article you first need to create an ASP.NET Core web application using Visual Studio. So, go ahead and do so based on any of the web application project templates. Make sure to use ASP.NET Core version 2.2 or later.

Once you create the project, click on the Build > Publish menu and Web Deploy the output (or manually copy to IIS) to IIS. Once you finish deploying the application locate the web.config file generated during the deployment process. In this web.config you will find a section like this:

<system.webServer>
  <handlers>
    <add name="aspNetCore" path="*" verb="*"
modules="AspNetCoreModuleV2" />
  </handlers>
  <aspNetCore processPath="dotnet"
              arguments=".\MyWebApp.dll"  
              stdoutLogEnabled="false"
              stdoutLogFile=".\logs\stdout"
              hostingModel="inprocess" />
</system.webServer>

As you can see the <aspNetCore> tag has hostingModel attribute that is set to inprocess by default.

Now, run the application from the browser with this default setting in place and observe the HTTP headers. The following figure shows one such sample run of the application.

As you can see the Server is Microsoft IIS.

Now, change the hostingModel attribute from inprocess to outofprocess. Run the application again. This time you will get the following output:

As you can see the Server is now Kestrel indicating that Out-Of-Process model is active.

In the preceding example you change the hosting model in the web.config generated during the publish operation. You can also specify the hosting model in project's .csproj file. Consider the following markup from .csproj file that does that.

<PropertyGroup>
    <TargetFramework>netcoreapp2.2</TargetFramework>
    <AspNetCoreHostingModel>InProcess</AspNetCoreHostingModel>
</PropertyGroup>

The <AspNetCoreHostingModel> element sets the hosting model to InProcess. To set it to Out-Of-Process you need to set it like this:

<AspNetCoreHostingModel>OutOfProcess</AspNetCoreHostingModel>

Run the application with these settings and confirm whether you get the outcome as before.

That's it for now! Keep coding!!

This code will help the developers to check and uncheck the gridview checkbox based on the value from the database.
Create a GridView with checkbox.

<asp:GridView ID="Gridview" runat="server" Font-Size="8pt" 
        PageSize="200" Width="880px" AutoGenerateColumns="False"> 
        <Columns> 
            <asp:TemplateField> 
                <HeaderTemplate> 
                    <asp:CheckBox ID="chkHeader" Text="Select All" runat="server" /> 
                </HeaderTemplate> 
                <ItemTemplate> 
                    <asp:CheckBox ID="chkChild" runat="server"  Checked='<%# Eval("PROCESSED").ToString().Equals("1") %>' Enabled='<%# !Eval("PROCESSED").ToString().Equals("1") %>'/> 
                </ItemTemplate> 
            </asp:TemplateField>            
        </Columns> 
    </asp:GridView> 

Get the data from the database, the field from the database to check the checkbox should be 1 or 0.

DB Table data

PROCESSED (HEADER)
1
1
0

DataField "PROCESSED" should be 1 or 0 (boolean),

Checked='<%# Eval("PROCESSED").ToString().Equals("1") %>' 

The above GridView code will check the checkbox if the value from the PROCESSED field in DB is 1 else if the PROCESSED value is other than 1 the checkbox will be unchecked,

Enabled='<%# !Eval("PROCESSED").ToString().Equals("1") %>' 

This code will help us to enable or disable the text box. In the above mentioned code, if the PROCESSED is 1, checkbox will be disabled else the checkboc will be enable.

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PROGRAMMING LANGUAGE SUPPORT
From a programming point of view C#, Visual Basic, and F# languages can be used to write applications and libraries for .NET Core. Additionally, with .NET Core 3.0 C# 8.0 will be supported. Currently, VB.NET compiles and runs on .NET Core, but the separate Visual Basic Runtime is not implemented. Microsoft announced that .NET Core 3 would include the Visual Basic Runtime.

Use .NET Core when

• You want to build cross-platform applications
• If the new application (web or service) needs to run on multiple platforms- Windows, Linux, macOS, choose .NET Core over .NET Framework. Visual Studio Code and third-party editors such as Sublime, Emacs, VI support .NET Core for cross-platform development.
• The need is to build high-performance and scalable systems
• When a performance-oriented and scalable system is on the list, it is better to prefer .NET Core over the .NET Framework. Reason being, .NET Core offers high-performance server runtime for Linux and Windows Server.
• When you are using microservices or Docker containers
• For applications or services that use microservices or Docker containers, opting .NET Core makes more sense. Reasons include,
  
  • .NET Core facilitates mixing microservices or services developed with Ruby, Java, .NET Framework, or other monolithic technologies.
  • Containers usually work in conjugation with microservices architecture. With .NET Framework, there is a limitation to work with Windows containers only. Moreover, while creating and deploying a container, the image size is smaller with .NET Core vs .NET Framework.
    
• You need side-by-side .NET versions per application
• For applications that may have a dependency on different versions of .NET for installation, opt for .NET Core. .NET Core offers side by side installation of multiple versions for .NET Core runtime on the same machine.

Use the .NET Framework when:

• The app is using .NET technologies that are not available for .NET Core.
• Several .NET technologies are not available for .NET Core. For example, ASP.NET web pages applications or workflow related services (WCF Data Services, Windows Workflow Foundation) are not included in. NET Core.
• The existing app uses a platform that .NET Core does not support.
• Some of the Microsoft or third-party services/platforms do not offer support to .NET Core. For example, Azure’s Service Fabric Stateful Reliable Services programming model does not support .NET Core and is available for.NET Framework.

There can be situations where you need to register multiple implementations of the same dependency for your applications. For example, if you want to add features to your application without changing the existing code, a good way to do it is to add a new implementation for that. Your application needs to be written in a certain way to do this correctly. We have a really simple example that demonstrates this in this article. But when you eventually need to do this, ASP.Net Core built-in Dependency Injection providers capabilities to achieve this. In this article, we will look at how to do this with an example.
Registering Multiple Implementations of a Dependency

As an example, let’s take an online e-commerce website. This site gives Discounts to the customers on certain occasions and when certain conditions are met. I have an interface called IDiscount where it defines a discount and the logic to calculate it. For each type of discount, you want to provide in your e-commerce application, you can have an implementation of the IDiscount interface. Then I have an interface called IDiscountProcessor where the implementation of this interface handles calling all the implementations of IDiscount to calculate the final discount for a given Order.

You have a couple of ways to register multiple implementations of a dependency in ASP.Net Core. One way is to just use the provided extension methods on IServiceCollection to register your implementations with the desired lifetime.
    services.AddScoped<IDiscountProcessor, OrderDiscountProcessor>(); 
    services.AddScoped<IDiscount, SeasonalDiscount>(); 
    services.AddScoped<IDiscount, LargeOrderDiscount>(); 
    services.AddScoped<IDiscount, ThreeOrModeDiscount>();  

Here, I have registered the OrderDiscountProcessor implementation of IDiscountProcessor and 3 implementations of IDiscount interface.

This will work fine when we eventually resolve all the implementations of IDiscount interface we can calculate the total discount. But the problem comes when you have multiple registrations of the same implementation. For example, let’s say one of the developers accidentally registered SeasonalDiscount implementation twice. What will happen is that the Seasonal discount will be applied twice for all the orders, costing the organization money.

A better way of registering multiple implementations is to use TryAddEnumerable extension method given in the Microsoft.Extensions.DependencyInjection.Extensions namespace. This will not register any duplicate implementations making multiple implementation registration safe. The registration is a bit different where you need to use ServiceDescriptors to register the dependency. The modified implementation looks like this.
    services.AddScoped<IDiscountProcessor, OrderDiscountProcessor>(); 
    services.TryAddEnumerable(new[] 
    { 
        ServiceDescriptor.Scoped<IDiscount, SeasonalDiscount>(), 
        ServiceDescriptor.Scoped<IDiscount, LargeOrderDiscount>(), 
        ServiceDescriptor.Scoped<IDiscount, ThreeOrModeDiscount>() 
    }); 

Injecting and Using Multiple Implementations of a Dependency

Once your implementations are registered with the Dependency Injection container, they are ready to be used. To inject all the registered implementations, you need to use IEnumerable<> of the implementation type in your constructor. So, your constructor would look something like this. This is our OrderDiscountProcessor implementation.
    public class OrderDiscountProcessor : IDiscountProcessor 
    { 
        private readonly IEnumerable<IDiscount> _discounts; 
     
        public OrderDiscountProcessor(IEnumerable<IDiscount> discounts) 
        { 
            _discounts = discounts; 
        } 
        // ... 
    } 

Here I am injecting IEnumerable<IDiscount> where it injects all the registered implementations to my class. Then in my ProcessDiscount() method I can use the implementations like this.
    public (double, List<string>) ProcessDiscount(OrderViewModel order) 
    { 
        var discountDiscroptoons = new List<string>(); 
        var totalDiscount = 0.0; 
     
        foreach (var discount in _discounts) 
        { 
            var addedDiscount = discount.CalculateDiscount(order); 
            if (addedDiscount > 0) 
            { 
                 discountDiscroptoons.Add(discount.Description); 
            } 
            totalDiscount += addedDiscount; 
        } 
     
        return (totalDiscount, discountDiscroptoons); 
     } 

I can now iterate through all the implementations of IDiscount interface and call its CalculateDiscount() method to calculate the discount for the given Order.

Note that you can only use IEnumerable<> for your injections of multiple implementations. Any other type like IList<>, ICollection<> will not work in this case.
Summary

In this article, we looked into the process of how to register multiple implementations of the same dependency in ASP.NET Core and how to use these dependencies in our classes by injecting them. The simple sample application used to demonstrate this usage is available for download with this article or you can find the source code on GitHub under the following repository

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I recently came across the need to host a .NET Core web app as a Windows Service. In this case, it was because each machine needed to locally be running an API. But it’s actually pretty common to have a web interface to manage an application on a PC without needing to set up IIS. For example if you install a build/release management tool such as Jenkins or TeamCity, it has a web interface to manage the builds and this is able to be done without the need for installing and configuring an additional web server on the machine.

Luckily .NET Core actually has some really good tools for accomplishing all of this (And even some really awesome stuff for being able to run a .NET Core web server by double clicking an EXE if that’s your thing).

A Standalone .NET Core Website/Web Server

The first step actually has nothing to do with Windows Services. If you think about it, all a Windows Service is, is a managed application that’s hidden in the background, will restart on a machine reboot, and if required, will also restart on erroring. That’s it! So realistically what we first want to do is build a .NET Core webserver that can be run like an application, and then later on we can work out the services part.

For the purpose of this tutorial, I’m just going to be using the default template for an ASP.net Core website. The one that looks like this:

We first need to head to the csproj file of our project and add in a specific runtime (Or multiple), and an output type. So overall my csproj file ends up looking like:

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <RuntimeIdentifiers>win10-x64;</RuntimeIdentifiers>
    <OutputType>Exe</OutputType>
  </PropertyGroup> 

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
  </ItemGroup>
</Project>

Our RuntimeIdentifiers (And importantly notice the “s” on the end there) specifies the runtimes our application can be built for. In my case I’m building only for Windows 10, but you could specify other runtime monkiers if required.

Ontop of this, we specify that we want an outputtype of exe, this is so we can have a nice complete exe to run rather than using the “dotnet run” command to start our application. I’m not 100% sure, but the exe output that comes out of this I think is simply a wrapper to boot up the actual application dll. I noticed this because when you change code and recompile, the exe doesn’t change at all, but the dll does.

Now we need to be able to publish the app as a standalone application. Why standalone? Because then it means any target machine doesn’t have to have the .NET Core runtime installed to get everything running. Ontop of that, there is no “what version do you have installed?” type talk. It’s just double click and run.

To publish a .NET Core app as standalone, you need to run the following command from the project directory in a command prompt/powershell:

dotnet publish --configuration Release --self-contained -r win10-x64

It should be rather self explanatory. We are doing a publish, using the release configuration, we pass through the self contained flag, and we pass through that the runtime we are building for is Windows 10 – 64 Bit.

From your project directory, you can head to:  \bin\Release\netcoreapp2.1\win10-x64\publish

This contains your application exe as well as all framework DLL’s to run without the need for a runtime to be installed on the machine. It’s important to note that you should be inside the Publish folder. One level up is also an exe but this is not standalone and relies on the runtime being installed.

From your publish folder, try double clicking yourapplication.exe.

Hosting environment: Production
Content root path: \bin\Release\netcoreapp2.1\win10-x64\publish
Now listening on: http://localhost:5000
Now listening on: https://localhost:5001
Application started. Press Ctrl+C to shut down.

In your browser head to http://localhost:5000 and you now have your website running from an executable. You can copy and paste this publish folder onto any Windows 10 machine, even a fresh install, and have it spin up a webserver hosting your website. Pretty impressive!

Installing As A Window Service

So the next part of this tutorial is actually kinda straight forward. Now that you have an executable that hosts your website, installing it as a service is exactly the same as setting up any regular application as a service. But we will try and have some niceties to go along with it.

First we need to do a couple of code changes for our app to run both as a service, and still be OK running as an executable (Both for debugging purposes, and in case we want to run in a console window and not as a service).

We need to install the following from your package manager console:

Install-Package Microsoft.AspNetCore.Hosting.WindowsServices

Next we need to go into our program.exe and make your main method look like the following:

public static void Main(string[] args)
{
 var isService = !(Debugger.IsAttached || args.Contains("--console"));
 var builder = CreateWebHostBuilder(args.Where(arg => arg != "--console").ToArray()); 

 if (isService)
 {

 var pathToExe = Process.GetCurrentProcess().MainModule.FileName;
 var pathToContentRoot = Path.GetDirectoryName(pathToExe);
 builder.UseContentRoot(pathToContentRoot);
 } 

 var host = builder.Build(); 

 if (isService)
 {
 host.RunAsService();
 }
 else
 {
 host.Run();
 }
}

This does a couple of things :

• It checks whether we are using the debugger, or if we have a console argument of “–console” passed in.
• If neither of the above are true, it sets the content root manually back to where the exe is running. This is specifically for the service runtime.
• Next if we are a service, we use a special “RunAsService()” method that .NET Core gives us
• Otherwise we just do a “Run()” as normal.

Obviously the main point of this is that if the debugger is attached (e.g. we are running from visual studio), or we run from a command prompt with the flag “–console”, it’s going to run exactly the same as before. Back in the day we used to have to run the service with a 10 second sleep at the start of the app, and quickly try and attach the debugger to the process before it kicked off to be able to set breakpoints etc. Now it’s just so much easier.

Now let’s actually get this thing installed!

In your project in Visual Studio (Or your favourite editor) add a file called install.bat to your project. The contents of this file should be:

sc create MyService binPath= %~dp0MyService.exe
sc failure MyService actions= restart/60000/restart/60000/""/60000 reset= 86400
sc start MyService
sc config MyService start=auto

Obviously replace MyService with the name of your service, and be sure to rename the exe to the actual name of your applications exe. Leave the %~dp0 part as this refers to the current batch path (Allowing you to just double click the batch file when you want to install).

The install file creates the service, sets up failure restarts (Although these won’t really be needed), starts the service, and sets the service to auto start in the future if the machine reboots for any reason.

Go ahead and create an uninstall.bat file in your project. This should look like:

sc stop MyService
timeout /t 5 /nobreak > NUL
sc delete MyService

Why the timeout? I sometimes found that it took a while to stop the service, and so giving it a little bit of a break inbetween stopping and deleting helped it along it’s way.

Important! For both of these files, be sure to set them up so they copy to the output directory in Visual Studio. Without this, your bat files won’t output to your publish directory.

Go ahead and publish your application again using our command from earlier:

dotnet publish --configuration Release --self-contained -r win10-x64

Now in your publish directory, you will find your install and uninstall bat files. You will need to run both of these as Administrator for them to work as installing Windows Services requires elevated access. A good idea is that the first time you run these, you run them from a command prompt so you can catch any errors that happen.

Once installed, you should be able to browse to http://localhost:5000 and see your website running silently in the background. And again, the best part is when you restart your machine, it starts automatically. Perfect!

Writing integration tests for ASP.NET Core controller actions used for file uploads is not a rare need. It is fully supported by ASP.NET Core integration tests system. This post shows how to write integration tests for single and multiple file uploads.

Getting started

Suppose we have controller action for file upload that supports multiple files. It uses complex composite command for image file analysis and saving. Command is injected to action by framework-level dependency injection using controller action injection.

[HttpPost]
[Authorize(Roles = "Admin")]
public async Task<IActionResult> Upload(IList<IFormFile> files, int? parentFolderId,
                                        [FromServices]SavePhotoCommand savePhotoCommand)
{
    foreach(var file in files)
    {
        var model = new PhotoEditModel();
        model.FileName = Path.GetFileName(file.FileName);
        model.Thumbnail = Path.GetFileName(file.FileName);
        model.ParentFolderId = parentFolderId;
        model.File = file;
 
        list.AddRange(savePhotoCommand.Validate(model));
 
        await savePhotoCommand.Execute(model);
    }
 
    ViewBag.Messages = savePhotoCommand.Messages;
 
    return View();
}

We want to write integration tests for this action but we need to upload at least one file to make sure that command doesn’t fail.

Making files available for integration tests

It’s good practice to have files for testing available no matter where tests are run. It’s specially true when writing code in team or using continuous integration server to run integration tests. If we don’t have many files and the files are not large then we can include those files in project.

Important thing is to specify in Visual Studio that these files are copied to output folder.

Same way it’s possible to use also other types of files and nobody stops us creating multiple folders or folder trees if we want to organize files better.

Uploading files in integration tests

Here is integration tests class for controller mentioned above. Right now there’s only one test and it is testing Upload action. Notice how image files are loaded from TestPhotos folder to file streams and how form data object is built using the file streams.

public class PhotosControllerTests : IClassFixture<WebApplicationFactory<Startup>>
{
    private readonly WebApplicationFactory<Startup> _factory;
 
    public PhotosControllerTests(WebApplicationFactory<Startup> factory)
    {
        _factory = factory;
    }
 
    [Fact]
    public async Task Upload_SavesPhotoAndReturnSuccess()
    {
        // Arrange
        var expectedContentType = "text/html; charset=utf-8";
        var url = "Photos/Upload";
        var options = new WebApplicationFactoryClientOptions { AllowAutoRedirect = false };
        var client = _factory.CreateClient(options);
 
        // Act
        HttpResponseMessage response;
 
        using (var file1 = File.OpenRead(@"TestPhotos\rt-n66u.jpg.webp"))
        using (var content1 = new StreamContent(file1))
        using (var file2 = File.OpenRead(@"TestPhotos\speedtest.png.webp"))
        using (var content2 = new StreamContent(file2))
        using (var formData = new MultipartFormDataContent())
        {
            // Add file (file, field name, file name)
            formData.Add(content1, "files", "rt-n66u.jpg.webp");
            formData.Add(content2, "files", "speedtest.png.webp");
 
            response = await client.PostAsync(url, formData);
        }
 
        // Assert
        response.EnsureSuccessStatusCode();
        var responseString = await response.Content.ReadAsStringAsync();
 
        Assert.NotEmpty(responseString);
        Assert.Equal(expectedContentType, response.Content.Headers.ContentType.ToString());
 
        response.Dispose();
        client.Dispose();
    }
}

For actions that accept only one file we need only one call to Add() method of formData.

Wrapping up

Integration tests mechanism in ASP.NET Core is flexible enough to support also more advanced scenarios like file uploads in tests. It’s not very straightforward and we can’t just call few methods of HTTP client to do it but it’s still easy enough once we know the tricks. If we keep test files in integration tests project then we don’t have to worry about getting files to machine where integration tests are running.

Many times, I have encountered a vital question: "How can I change 20000.00 to $20,000.00?" This involves a simple currency formatter. You can use either jQuery or server-side coding to show the currency in this format. Here, in this post, I will show you how to format the currency input from user in ASP.NET.
Format Currency using jQuery

First, start with jQuery. Google has provided a very simple way to format currency. You can find out about it from here. Or you can follow this.

To continue, you have to download two JavaScript files. One is jquery.formatCurrency-1.4.0.js and the second one is jquery.min.js. I have attached these JS files with the code I have attached along with this post.

So, let's start with sample coding. First, create a new project and add a new page, name it whatever you want. Then, add a new text box. Firstly, we will do it with the onBlur function of jQuery, so we don't need any more extra buttons for showing our formatted currency.

Add those downloaded JS files into your header section of the web form. And then, paste the following code into your page.

JS
    <script src="jquery.min.js"></script> 
    <script src="jquery.formatCurrency-1.4.0.js"></script> 
    <script type="text/javascript"> 
            $(document).ready(function () { 
                $('.text').focusout(function () { 
                    $('.text').formatCurrency(); 
                    $('.text').formatCurrency('.currencyLabel'); 
                }); 
            });        
    </script> 

HTML
    <div> 
         <p>Currency Formatter</p> 
         <asp:TextBox runat="server"  
     
         ID="txtPrice" CssClass="text"></asp:TextBox> 
         Show by Jquery: <span class="currencyLabel"></span> 
    </div> 

Check the CssClass of text box. It's the method by which formatCurrency() method is calling to format it to text box and also show the output value to a span.
Format Currency using C#

I hope it's clear to you how to format currency by jQuery. Now, let's see how to do this using C#. Don't worry, C# has an inbuilt function for this. For C#, we are taking an extra button to display the output into a label.

    <asp:TextBox ID="txtCurrency" runat="server"></asp:TextBox> 
    <asp:Button ID="btnChange" Text="Format" runat="server" OnClick="btnChange_Click"   /> 
    <asp:Label ID="lblShow" runat="server"></asp:Label> 
     
    protected void btnChange_Click(object sender, EventArgs e) 
    { 
        lblShow.Text = (Convert.ToDouble(txtCurrency.Text)).ToString("C2"); 
    } 

Make sure this method is only applicable to data types like decimal and double. So you have to add a check to see whether user input is bound to numbers.