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Asked: 2026-05-11T01:35:06+00:00

This is a Windows Forms application. I have a function which captures some mouse

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This is a Windows Forms application. I have a function which captures some mouse events modally till a condition is met. For example, I would like to wait for the user to select a point in the window’s client area (or optionally cancel the operation using the Escape key) before the function returns. I am using the following structure:

Application::AddMessageFilter(someFilter); while(someFilter->HasUserSelectedAPoint_Or_HitEscapeKey()){     Application::DoEvents(); } Application::RemoveMessageFilter(someFilter);

This works quite nicely except for taking up nearly 100% CPU usage when control enters the while loop. I am looking for an alternative similar to what is shown below:

Application::AddMessageFilter(someFilter); while(someFilter->HasUserSelectedAPoint_Or_HitEscapeKey()){     // Assuming that ManagedGetMessage() below is a blocking     // call which yields control to the OS     if(ManagedGetMessage())         Application::DoEvents(); } Application::RemoveMessageFilter(someFilter);

What is the right way to use IMessageFilter and DoEvents? How do I surrender control to the OS till a message is received? Any GetMessage equivalent in the managed world?

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1 Answer

  1. You could sleep the thread for 500ms or so between DoEvents() calls. Experiment with different values to see what feels right.

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