Draw Rectangle on top of screen/Desktop

[cheng_sh]

Hello everybody,

Is it possible to use VB.NET to draw a Rectangle on top of the screen/desktop? Can somebody teach me how to do that?

 

Thank you very much.

[cheng_sh]

Can anybody tell me what's wrong with my code here? I try to draw a rectangle on my desktop.

 

 

 

 

 

Public Class Win32

Public Declare Function GetDC Lib "user32" (ByVal hwnd As Integer) As Integer

Public Declare Function ReleaseDC Lib "user32" (ByVal hwnd As Long, ByVal hdc As Long) As Long

Public Declare Function GetDesktopWindow Lib "user32" () As Integer

 

End Class

 

 

Sub Main()

Dim rWorkArea As Rectangle

Dim m_graph As Graphics

Dim hwnd As Integer

Dim m_lHwnd As Long

Dim m_lHdc As Integer

 

hwnd = Win32.GetDesktopWindow

m_lHdc = Win32.GetDC(hwnd)

rWorkArea = Screen.GetWorkingArea(Screen.PrimaryScreen.WorkingArea)

 

Dim hdc As IntPtr

hdc = IntPtr.op_Explicit(m_lHdc)

m_graph = Graphics.FromHdc(hdc)

 

Dim redPen As New Pen(Color.Red, 4)

' Draw rectangle with GDI+.

m_graph.DrawRectangle(redPen, rWorkArea)

 

'm_graph.ReleaseHdc(hdc)

Win32.ReleaseDC(hwnd, m_lHdc)

end sub

[mutant]

What errors are you getting?

[cheng_sh]

No error but just can't see the rectangle that's suppose to be on top of the desktop.

 

Thank you for your reply.

[cheng_sh]

Can somebody kindly teach me about this?

 

Thank you very much.