Visual Basic .NET

Using WndProc

It is a method of using event message routine as a function of Visual Basic .NET.(It is called VB .NET later)

When using WndProc, the event message routine is called whenever all events related to the application are generated.

Creating event message routine

When using WndProc in VB .NET, the corresponding code cannot be generated automatically,
please add the source code related to the event message routine manually.

Create the function according to the following procedure.

1. Declare the function
   By using the Message Structure in the Class of System.Windows.Forms namespace, it is possible to acquire the information related to messages being sent to the application and controls etc. from the system.
   
   Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)

2. Handling
   
   For example: Output"Interval timer event"
   
   If m.Msg = TIMM_INTERVAL Then
   
   Text_ErrorString.Text = "Interval timer event"
   
   End If

3. WndProc handling of the base class
   Perform the handling at the end of the WndProc function.
   
   MyBase.WndProc(m)

4. Combining 1, 2 and 3, the event message routine is as follows.

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)

If m.Msg = TIMM_INTERVAL Then

Text_ErrorString.Text = "Interval timer event"

End If

MyBase.WndProc(m)

End Sub

Specifying window handle

To use the event, it is necessary to set the window handle of the application to the driver.
Use the following function for event setting.

Specify the window handle to the hWnd parameter in the event setting function.

In Visual Basic .NET, the Handle member variable of the .NET Framework class owns the window handle. Please specify the member variable "as is" (At the same time, cast it with the ToInt32 method).