How do I register a .NET DLL file in the GAC?

I have made a .NET .DLL file, which I want to register in the GAC.

I have used this command in Windows Server 2003 Command Prompt:

C:\"Path of dll"\>gacutil /i dllname.dll
'gacutil' is not recognized as an internal or external command,
operable program or batch file.

It says the path is not correct.

Do I need to use this in a .NET cmd prompt? If it is that, I am not able to locate the .NET cmd prompt.

You can do that using the gacutil tool. In its simplest form:

gacutil /i yourdll.dll

You find the Visual Studio Command Prompt in the start menu under Programs -> Visual Studio -> Visual Studio Tools.

You'll need:

• Strong name your assembly (Visual Studio, Project Properties, Signing tab, Sign the assembly)
• Alter your Build Events (Project Properties, Build Events tab, Post-build command line)

   cd C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin
   gacutil.exe /i "$(TargetPath)" /f /nologo
   gacutil /l "$(TargetName)" /nologo

Now, everytime you build your project, it'll be installed on GAC.

Just drag and drop the DLL file into folder C:\Windows\assembly using Windows Explorer.

Caveat:

In earlier versions of the .NET Framework, the Shfusion.dll Windows shell extension let you install assemblies by dragging them to File Explorer. Beginning with .NET Framework 4, Shfusion.dll is obsolete.

Source: How to: Install an assembly into the global assembly cache

These responses don't tell you that gacutil resides in C:\WINDOWS\Microsoft.NET\Framework\v1.1* by the way.

I didn't have it in my v2.0 folder. But I tried dragging & dropping the DLL into the C:\WINDOWS\Assembly folder as was suggested here earlier and that was easier and does work, as long as it's a .NET library. I also tried a COM library and this failed with an error that it was expecting an assembly manifest. I know that wasn't the question here, but thought I'd mention that in case someone finds out they can't add it, that that might be why.

-Tom