[.net] How to run regasm.exe from command line other than Visual Studio command prompt?

I want to run regasm.exe from cmd. which is available in c:\windows\Microsoft.net\framework\2.057

I do like this c:\ regasm.exe

It gives regasm is not recognized as internal or external command.

So I understood that I need to set the path for regasm.exe in environment variable.

For which variable do I need to set the path to run regasm as described above?

I really dislike the hard coding of paths to get to regasm, when you install a new .Net or run on a machine with a different version, you need to ensure you find a version of regasm. Here's a solution to find the regasm.exe from the most current .Net installed regasm.

Within a bat file:

for /f %%a in ('dir %windir%\Microsoft.Net\Framework\regasm.exe /s /b') do set currentRegasm="%%a"
%currentRegasm% "full\path\to\your.dll" /options

Outside of a bat file (i.e. command prompt), just use %a instead of %%a

Execute only 1 of the below
Once a command works, skip the rest/ below to it:

Normal:

%SystemRoot%\Microsoft.NET\Framework\v4.0.30319\RegAsm.exe myTest.dll
%SystemRoot%\Microsoft.NET\Framework\v4.0.30319\RegAsm.exe myTest.dll /tlb:myTest.tlb
%SystemRoot%\Microsoft.NET\Framework\v4.0.30319\RegAsm.exe myTest.dll /tlb:myTest.tlb /codebase

Only if you face issues, use old version 'v2.0.50727':

%SystemRoot%\Microsoft.NET\Framework\v2.0.50727\RegAsm.exe myTest.dll
%SystemRoot%\Microsoft.NET\Framework\v2.0.50727\RegAsm.exe myTest.dll /tlb:myTest.tlb
%SystemRoot%\Microsoft.NET\Framework\v2.0.50727\RegAsm.exe myTest.dll /tlb:myTest.tlb 

Only if you built myTest.dll for 64bit Only, use 'Framework64' path:

%SystemRoot%\Microsoft.NET\Framework64\v4.0.30319\RegAsm.exe myTest.dll
%SystemRoot%\Microsoft.NET\Framework64\v2.0.50727\RegAsm.exe myTest.dll

Note: 64-bit built dlls will not work on 32-bit platform.

All options:

See https://docs.microsoft.com/en-us/dotnet/framework/tools/regasm-exe-assembly-registration-tool

By dragging and dropping the dll onto 'regasm' you can register it. You can open two 'Window Explorer' windows. One will contain the dll you wish to register. The 2nd window will be the location of the 'regasm' application. Scroll down in both windows so that you have a view of both the dll and 'regasm'. It helps to reduce the size of the two windows so they are side-by-side. Be sure to drag the dll over the 'regasm' that is labeled 'application'. There are several 'regasm' files but you only want the application.

If you created the DLL using .net 4.5 , then copy and paste this command on command prompt.

 %SystemRoot%\Microsoft.NET\Framework\v4.0.30319\regasm.exe MyAssembly.dll

For the 64-bit RegAsm.exe you will need to find it someplace like this:

c:\Windows\Microsoft.NET\Framework64\version_number_stuff\regasm.exe

Like Cheeso said:

You don't need the directory on your path. You could put it on your path, but you don't NEED to do that. If you are calling regasm rarely, or calling it from a batch file, you may find it is simpler to just invoke regasm via the fully-qualified pathname on the exe, eg:

%SystemRoot%\Microsoft.NET\Framework\v2.0.50727\regasm.exe MyAssembly.dll

I use the following in a batch file:

path = %path%;C:\Windows\Microsoft.NET\Framework\v2.0.50727
regasm httpHelper\bin\Debug\httpHelper.dll /tlb:.\httpHelper.tlb /codebase
pause

You don't need the directory on your path. You could put it on your path, but you don't NEED to do that.
If you are calling regasm rarely, or calling it from a batch file, you may find it is simpler to just invoke regasm via the fully-qualified pathname on the exe, eg:

c:\Windows\Microsoft.NET\Framework\v2.0.50727\regasm.exe   MyAssembly.dll

I use this as post-build event in Visual Studio:

call "%VS90COMNTOOLS%vsvars32.bat"
regasm  $(TargetPath) /tlb

Depending on your Visual Studio version, use these environment variables instead:

1. Visual Studio 2008: VS90COMNTOOLS
2. Visual Studio 2010: VS100COMNTOOLS
3. Visual Studio 2012: VS110COMNTOOLS
4. Visual Studio 2013: VS120COMNTOOLS
5. Visual Studio 2015: VS140COMNTOOLS
6. Visual Studio 2017: VS150COMNTOOLS