How to capture/store screen shot

We all are familiar with taking screen shot manully by pressing “Print Screen" key. There are two alternative for using “Print Screen" key

1) Alt+PrtScn -Image of active screen
2) PrtScn - Image of Desktop

Here I am trying to simulating above two method using C#.

     /// <summary>
    /// capture/store the screen shot
    /// </summary>
    /// <param name="currentScreen"> true-Active screen   </param>
    /// <returns>image</returns>
    public static Image GetScreenShot(bool currentScreen)
    {
 
        if (currentScreen)
            // Simulate Alt+PrtScn keypress.
            SendKeys.Send("{%}({PRTSC})");
        else
            // Simulate PrtScn keypress.
            SendKeys.Send("{PRTSC}");
 
        // Get the image from the clipboard.
        return (Image)Clipboard.GetImage();
 
    }