Installing DLL Into GAC Using Powershell

To install DLL into Global Assembly Cache (GAC) you need Visual Studio or SDK to run gacutil.exe. It’s not convenient when you need to deploy ASP.NET application in IIS. This time you can do this with Powershell as described in TechNet article How to Install a DLL to the GAC on Windows Server 2012 Using Only PowerShell by Muhammad Khalid Latif.

Line Number In C# Program

I have a method in ASP.NET application that works good but sometimes it fails. I need some kind of error logging or tracing. If you don’t want to write stupid messages everywhere in your code, you have some possibilities.

In debug mode:
1. Embrace your code in try-catch block. Compile the application in debug mode and place .pdb file along with .exe file. When the error is occurred, exception will show the line number.
2. You can write trace info manually as described by Scott Hanselman in Getting the Line Number and File Name from C#.

.pdb file is necessary here, or you’ll see 0 instead of a line number.

In release mode:
Thanks to Marc Gravell, but you need .NET Framework 4.5 or higher here.

Casting C# Enums

It’s a short memo how to cast enum to int or string and vice versa.

1. Enum -> int
int value = (int)myEnum;

2. Enum -> string
string name = myEnum.ToString();

3. Int -> Enum
myEnum = (MyEnum)2;

4. String -> Enum
myEnum = (MyEnum) Enum.Parse(typeof(MyEnum), stateName);
bool parseSuccess = Enum.TryParse(stateName, out myEnum);

Unit Testing C# Async Methods

This time I have a C# async method that should be tested. As you remember, async method must return Task or Task<>.  You can declare an async void method, but this should be used only for event handlers because you have no control on method execution and, the most important, its failure. Beside that, async void method is hard to test.

I have a simple async method that returns Task<int> instead of int in synchronous method (look at my previous post Unit Testing C# Synchronous Methods).

We must be happy that modern unit test frameworks allow to write async unit test where an async method is called asynchronously.

1. Check successful result

The async method being tested is called via await operator. This makes the code being executed in true asynchronous mode.

2.1. Check failure with ThrowsAsync<>

Unit test is awaiting for result from Assert.ThrowsAsync, that is awaiting for result from the method being tested. If you delete the inner async/await, the method would be executed in synchronous mode. If you omit the first outer await, the unit test method might finish before the code in NumberAsync would fail. So you will get wrong results!

2.2. Check failure with Record.ExceptionAsync

Unit Testing C# Synchronous Methods

When you need to unit test a method, you should check happy path (for example, the method returns a resulting value) and sad path (the method throws exception). Here I describe a basic usage of unit testing with Visual Studio 2017 and xUnit version 2.2.

The code being tested:

1. Check successful result (happy path) – it’s very straightforward.

2. Check fail when the method throws an exception (sad path)

If you have faced with MSTest, you might remember [ExpectedException] attribute. In this case MSTest waits for a particular exception would be thrown in a whole unit test method, but not in a specific line of code. Modern unit test frameworks have more graceful capabilities to catch the exception.

2.1. Using Throws<>

But this approach combines Act and Assert phases of unit test in one line of code. Richard Banks suggested a better way in his article Stop Using Assert.Throws in Your BDD Unit Tests.

2.2. Using Record.Exception

At first, I check that the exception was really caught, then check the type of that exception.

Next time I’ll tell about unit testing the asynchronous methods.

Creating GitHub Project In Visual Studio 2017

My goal is to create a new solution and place it in GitHub. This can be done in few steps:

1. Create a GitHub account.
2. Install a GitHub extension for Visual Studio. I’ve downloaded it from
3. Start Visual Studio, open Team Explorer and connect to GitHub.

4. Create a new GitHub repository.

Click link, and enter data in the next form.

5. Switch back to Team Explorer. Click Create a new project or solution link.

6. Choose project type, give it a name. Step forward on wizard steps.

After that you will have the following structure in Visual Studio

and in a disk folder

Now you can write code, commit changes and push them to GitHub.

Converting List To IDataReader

I wrote about using SqlBulkCopy to fast load data from .NET into SQL Server database. This class needs a DataTable or IDataReader instance as a source. You can convert a C# List to DataTable (look here Converting List To DataTable). Now I’ll show a couple of examples how to convert List to IDataReader.

1. Straight implementation of IDataReader interface
I’ve seen a couple of good examples from Bruce Dunwiddie and Venu Gopal Based on these two solutions I’ve made my one.

Now you can iterate through IDataReader like you do with SqlDataReader.

2. FastMember NuGet package

Thank you, Marc! it’s a good job

You need to install NuGet package FastMember, add using FastMember; statement, and run this code.

Converting List To DataTable

In my previous post SqlBulkCopy I wrote about how to load data from .NET code into SQL Server database using efficient BULK INSERT command. This class needs a DataTable or IDataReader instance as a source. I’ve collected a couple of examples how to convert List to DataTable.

1. Variation of Marc Gravell solution.

2. Solution created by Jennifer Hubbard, Bill Wagner, etc.
Source: How to: Implement CopyToDataTable<T> Where the Generic Type T Is Not a DataRow


SQL Server have great commands like BULK INSERT or OPENROWSET(BULK…) to insert a huge amount of data into a database. .NET Framework has a class SqlBulkCopy that provides similar capabilities in C#. Full documentation is available on MSDN article SqlBulkCopy Class. But SqlBulkCopy has some restrictions on input data. It can read from:

  • DataRow[] array;
  • DataTable;
  • IDataReader.

A simple example of usage can be as follows:

SQL Server Profiler shows that the correct command was really executed.

In order to use SqlBulkCopy class elegantly, it would better to have a method or extension to convert a generic list to DataTable or IDataReader. But it’s a topic for my next post.

Offline Installer For Visual Studio 2017

Microsoft does not offer an ISO image for Visual Studio 2017, we need to make it ourselves by running web installer with some command-line arguments. Here are the links to official pages:

Create an offline installer for Visual Studio 2017

Visual Studio 2017 workload and component IDs

Example to grab community edition:

Layout parameter is mandatory, it points to a folder where the downloaded files would be saved.
Workload_id_list is a list of component IDs, separated by space. If you skip it, all components will be downloaded.

[UPDATE 2017-06-21]
Workloads contain only the recommended components. As mentioned by geoyar, you need to include optional components manually.

Component ID Description
Visual Studio core editor (included with Visual Studio Community 2017) Microsoft.VisualStudio.Workload.CoreEditor The Visual Studio core shell experience, including syntax-aware code editing, source code control and work item management.
Azure development Microsoft.VisualStudio.Workload.Azure Azure SDK, tools, and projects for developing cloud apps and creating resources.
Data storage and processing Microsoft.VisualStudio.Workload.Data Connect, develop and test data solutions using SQL Server, Azure Data Lake, Hadoop or Azure ML.
.NET desktop development Microsoft.VisualStudio.Workload.ManagedDesktop Build WPF, Windows Forms and console applications using the .NET Framework.
Game development with Unity Microsoft.VisualStudio.Workload.ManagedGame Create 2D and 3D games with Unity, a powerful cross-platform development environment.
Linux development with C++ Microsoft.VisualStudio.Workload.NativeCrossPlat Create and debug applications running in a Linux environment.
Desktop development with C++ Microsoft.VisualStudio.Workload.NativeDesktop Build classic Windows-based applications using the power of the Visual C++ toolset, ATL, and optional features like MFC and C++/CLI.
Game development with C++ Microsoft.VisualStudio.Workload.NativeGame Use the full power of C++ to build professional games powered by DirectX, Unreal, or Cocos2d.
Mobile development with C++ Microsoft.VisualStudio.Workload.NativeMobile Build cross-platform applications for iOS, Android or Windows using C++.
.NET Core cross-platform development Microsoft.VisualStudio.Workload.NetCoreTools Build cross-platform applications using .NET Core, ASP.NET Core, HTML, JavaScript, and CSS
Mobile development with .NET Microsoft.VisualStudio.Workload.NetCrossPlat Build cross-platform applications for iOS, Android or Windows using Xamarin.
ASP.NET and web development Microsoft.VisualStudio.Workload.NetWeb Build web applications using ASP.NET, ASP.NET Core, HTML, JavaScript, and CSS.
Node.js development Microsoft.VisualStudio.Workload.Node Build scalable network applications using Node.js, an asynchronous event-driven JavaScript runtime.
Office/SharePoint development Microsoft.VisualStudio.Workload.Office Create Office and SharePoint add-ins, SharePoint solutions, and VSTO add-ins using C#, VB, and JavaScript.
Universal Windows Platform development Microsoft.VisualStudio.Workload.Universal Create applications for the Universal Windows Platform with C#, VB, JavaScript, or optionally C++.
Visual Studio extension development Microsoft.VisualStudio.Workload.VisualStudioExtension Create add-ons and extensions for Visual Studio, including new commands, code analyzers and tool windows.
Mobile development with JavaScript Microsoft.VisualStudio.Workload.WebCrossPlat Build Android, iOS and UWP apps using Tools for Apache Cordova.
Unaffiliated components Component.GitHub.VisualStudio GitHub extension for Visual Studio
Unaffiliated components Microsoft.Component.Blend.SDK.WPF Blend for Visual Studio SDK for .NET
Unaffiliated components Microsoft.Component.HelpViewer Help Viewer
Unaffiliated components Microsoft.Net.Component.3.5.DeveloperTools .NET Framework 3.5 development tools
Unaffiliated components Microsoft.VisualStudio.Component.DependencyValidation.Community Dependency Validation
Unaffiliated components Microsoft.VisualStudio.Component.LinqToSql LINQ to SQL tools
Unaffiliated components Microsoft.VisualStudio.Component.TestTools.Core Testing tools core features
Unaffiliated components Microsoft.VisualStudio.Component.TypeScript.2.0 TypeScript 2.0 SDK
vs_community__1238641179.1486458197.exe –layout C:\VS2017 –lang en-US –add Microsoft.VisualStudio.Workload.CoreEditor Microsoft.VisualStudio.Workload.Azure Microsoft.VisualStudio.Workload.Data Microsoft.VisualStudio.Workload.ManagedDesktop Microsoft.VisualStudio.Workload.NetCoreTools Microsoft.VisualStudio.Workload.NetWeb Microsoft.VisualStudio.Workload.Node Microsoft.VisualStudio.Workload.Office Microsoft.VisualStudio.Workload.VisualStudioExtension Component.GitHub.VisualStudio Microsoft.Component.Blend.SDK.WPF Microsoft.Component.HelpViewer Microsoft.Net.Component.3.5.DeveloperTools Microsoft.VisualStudio.Component.DependencyValidation.Community Microsoft.VisualStudio.Component.LinqToSql Microsoft.VisualStudio.Component.TestTools.Core Microsoft.VisualStudio.Component.TypeScript.2.0