How To Check If A Window Is Minimized In C#

Question

Hello, I need to check if a window is minimized in c# Here is what I did:

{
    class RestoreWindow
    {
        [DllImportAttribute("user32.dll")]
public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

[DllImportAttribute("user32.dll")]
public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

[DllImportAttribute("user32.dll")]
public static extern bool SetForegroundWindow(IntPtr hWnd);

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool IsIconic(IntPtr hWnd);

public static void MaximizeWindowIfMinized(string windowName,Form f1)
{
    try
    {
        var instance = FindWindow(null, windowName);

        if (IsIconic(instance))
        {
            Button btn = new Button();
            btn.Width = 10;
            btn.Height = 10;
            f1.Controls.Add(btn);
            MessageBox.Show("Window is minimized");

           // ShowWindow(instance, 1);
            //SetForegroundWindow(instance);
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}
    }
}

But when I compile nothing happen , do you have any idea ?