Can't import User32.dll into Visual Studio

Question

I tried:

• To add user32.dll from Reference Manager, and imported it from Windows\System32\user32.dll, I got Error Message:

  A reference to 'C:\Windows\System32\user32.dll couldn't be added. Please make sure that the file is accessible, and that it is a valid assembly or COM component.

• using System.Runtime.InteropServices; [DllImport("user32")]

• To launch Visual Studio as Administrator

Nothing works... it goes on my nerves I am trying 2 hours to import this damn .dll...

Answer 1

You do not need to add a reference to User32.dll. It is part of Windows and can be imported in your code without adding a reference. You do this using P/Invoke.

[System.Runtime.InteropServices.DllImport("user32.dll")]
public static extern void SetWindowText(int hWnd, String text);

private void button3_Click(object sender, EventArgs e)
{
    IntPtr wHnd = this.Handle;//assuming you are in a C# form application
    SetWindowText(wHnd.ToInt32(), "New Window Title");
}

See Also:

• Using P/Invoke from MSDN
• Calling API Functions

Answer 2

It's not a .NET dll. You don't "add reference" the same way you do with .NET dlls. Instead you have to add P/Invoke code to your app to invoke the functions you want. Here's a good resource for learning pinvoke: http://pinvoke.net/