Forms Application Base. Do Events Method
Processes all Windows messages currently in the message queue.
public: void DoEvents();
public void DoEvents ();
member this.DoEvents : unit -> unit
Public Sub DoEvents ()
This example uses the
My.Application.DoEvents method to allow the UI for
TextBox1 to update.
Private Sub TestDoEvents() For i As Integer = 0 To 10000 TextBox1.Text = i.ToString My.Application.DoEvents() Next End Sub
This code should be in a form that has a
TextBox1 component with a
My.Application.DoEvents method allows your application to handle other events that might be raised while you code runs. The
My.Application.DoEvents method has the same behavior as the DoEvents method.
When you run a Windows Forms application, it creates a new form, which then waits for events to be handled. Each time the form handles an event, such as a button click, it processes all the code associated with that event. All other events wait in the queue. While your code handles the event, your application does not respond. For example, the window does not repaint if another window is dragged on top.
If you call
My.Application.DoEvents in your code, your application can handle the other events. For example, if your code adds data to a ListBox in a loop, and after each step of the loop it calls
My.Application.DoEvents, your form repaints when another window is dragged over it. If you remove
My.Application.DoEvents from your code, your form will not repaint until the click event handler of the button is finished executing.
Typically, you use this method in a loop to process messages.
My.Application.DoEvents method does not process events in exactly the same way as the form does. Use multithreading to make the form directly handle the events. For more information, see Multithreaded Applications.
If a method that handles a user interface (UI) event calls the
My.Application.DoEvents method, the method might be re-entered before it finishes. This can happen because the
My.Application.DoEvents method processes Windows messages, and Windows messages can raise events.
The following table lists an example of a task involving the
|Allow a form to respond to UI input while busy||Walkthrough: Handling Events|
Availability by Project Type
|Windows Forms Application||Yes|
|Windows Forms Control Library||No|
|Web Control Library||No|