C# – How to get the .NET framework version that the application is using

I have referred to the Stack Overflow question Is there an easy way to check the .NET Framework version?. But the suggestions given there did not work for the following purpose.

How can we identify the .NET version that the C# console application is using?

Environment:

Visual Studio 2010
.NET Framework: 3.5 (please see attached screenshot)

CODE

using System;
using System.Globalization;
using Microsoft.Win32;
namespace TESTConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            //.NET version: Approach 1
            RegistryKey installed_versions = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP");
            string[] version_names = installed_versions.GetSubKeyNames();
            double latestFramework = Convert.ToDouble(version_names[version_names.Length - 1].Remove(0, 1), CultureInfo.InvariantCulture);
            int SP = Convert.ToInt32(installed_versions.OpenSubKey(version_names[version_names.Length - 1]).GetValue("SP", 0));
            Console.WriteLine(latestFramework);

            //Approach 2
            string versionval = Environment.Version.ToString();
            Console.WriteLine(versionval);

            //Approach 3
            string systemVersionVal = System.Runtime.InteropServices.RuntimeEnvironment.GetSystemVersion().ToString();
            Console.WriteLine(systemVersionVal);

            Console.ReadLine();
        }
    }
}

Output

Enter image description here

VERSION Setup

Enter image description here

Best Answer

The 2nd and 3rd approached are the CLR version numbers.

.NET Framework 2 and .NET Framework 3.5 are using CLR 2.0.

And there's no CLR 3.0 or 3.5.

Related Solutions

C# – How to get the index of the current iteration of a foreach loop

Ian Mercer posted a similar solution as this on Phil Haack's blog:

foreach (var item in Model.Select((value, i) => new { i, value }))
{
    var value = item.value;
    var index = item.i;
}

This gets you the item (item.value) and its index (item.i) by using this overload of LINQ's Select:

the second parameter of the function [inside Select] represents the index of the source element.

The new { i, value } is creating a new anonymous object.

Heap allocations can be avoided by using ValueTuple if you're using C# 7.0 or later:

foreach (var item in Model.Select((value, i) => ( value, i )))
{
    var value = item.value;
    var index = item.i;
}

You can also eliminate the item. by using automatic destructuring:

<ol>
foreach ((MyType value, Int32 i) in Model.Select((value, i) => ( value, i )))
{
    <li id="item_@i">@value</li>
}
</ol>

C# – Should ‘using’ directives be inside or outside the namespace

There is actually a (subtle) difference between the two. Imagine you have the following code in File1.cs:

// File1.cs
using System;
namespace Outer.Inner
{
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now imagine that someone adds another file (File2.cs) to the project that looks like this:

// File2.cs
namespace Outer
{
    class Math
    {
    }
}

The compiler searches Outer before looking at those using directives outside the namespace, so it finds Outer.Math instead of System.Math. Unfortunately (or perhaps fortunately?), Outer.Math has no PI member, so File1 is now broken.

This changes if you put the using inside your namespace declaration, as follows:

// File1b.cs
namespace Outer.Inner
{
    using System;
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now the compiler searches System before searching Outer, finds System.Math, and all is well.

Some would argue that Math might be a bad name for a user-defined class, since there's already one in System; the point here is just that there is a difference, and it affects the maintainability of your code.

It's also interesting to note what happens if Foo is in namespace Outer, rather than Outer.Inner. In that case, adding Outer.Math in File2 breaks File1 regardless of where the using goes. This implies that the compiler searches the innermost enclosing namespace before it looks at any using directive.

Best Answer

Related Solutions

C# – How to get the index of the current iteration of a foreach loop

C# – Should ‘using’ directives be inside or outside the namespace

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