Try the following code, this is vary simple:
private void GetCurrentScreenResolution()
{
int intDeskHeight = Screen.PrimaryScreen.Bounds.Height;
int intDeskWidth = Screen.PrimaryScreen.Bounds.Width;
MessageBox.Show("Your screen resolution is " + intDeskWidth + "x" + intDeskHeight);
}
NOTE: Thanks to Mika Wendelius, the above code is implement from your suggestion.