public delegate bool WNDENUMPROC ( IntPtr hwnd, int lParam);

[ DllImport ( "user32.dll" )]

public static extern int EnumWindows( WNDENUMPROC lpEnumFunc, int lParam);

public static bool EnumFunc( IntPtr hwnd, int lParam)

{

    Console . WriteLine( "Window handle is " + hwnd);

    return true ;

}

private void button1_Click( object sender , EventArgs e)

{

   EnumWindows(EnumFunc, 0 );

}

//--------------------------

using System . Runtime . InteropServices;

public delegate bool EnumWindowsProc ( IntPtr hWnd, IntPtr lParam);

[ DllImport ( "user32.dll" )]

public static extern int EnumWindows( EnumWindowsProc lpEnumFunc, IntPtr lParam);

[ DllImport ( "user32.dll" )]

public static extern int GetWindowText( IntPtr hWnd,         StringBuilder lpString, int nMaxCount);

public static bool WindowsProc( IntPtr hWnd, IntPtr lParam)

{

    StringBuilder vBuffer = new StringBuilder ( 256 );

   GetWindowText(hWnd, vBuffer, vBuffer . Capacity);

    string S = vBuffer . ToString();

    int I = S . IndexOf( "_QQMusic_SmallClient" );

    if (I > 0 )

   {

       S = S . Remove(I);

        Console . WriteLine(S);

        return false ;

   }

    return true ;

}