Can't import User32.dll into Visual Studio

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...

Solution

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");
}