[MFC] Refreshing Picture Control

[Skizmo]

Please use code tags for posting readable code.

You can use Invalidate to force a window to redraw itself.

Some notes on your code.

In the OnRead...

CComPort* pComPort = new CComPort(g_sComPort);

This is never freed, so you have a memory leak.

In the OnPaint...

CGPSDlg m_bridge;
y=m_bridge.m_nLatitude;

You are creating a new window in the OnPaint. This will slow down your paint, because creating a new window is relatively a intensive job, and the OnPaint can be triggered a lot of times without you knowing it. Also, the class is new, so the m_nLatitude has it's default value, not the value you put in there during the OnRead function.