Message Methods

Message methods implement responses to dynamically dispatched messages. The message method syntax is supported on all platforms. VCL uses message methods to respond to Windows messages.

A message method is created by including the message directive in a method declaration, followed by an integer constant between 1 and 49151 which specifies the message ID. For message methods in VCL controls, the integer constant can be one of the Win32 message IDs defined, along with corresponding record types, in the Messages unit. A message method must be a procedure that takes a single var parameter.

For example:


TTextBox = class(TCustomControl) private procedure WMChar(var Message: TWMChar); message WM_CHAR; end;

A message method does not have to include the override directive to override an inherited message method. In fact, it doesn't have to specify the same method name or parameter type as the method it overrides. The message ID alone determines which message the method responds to and whether it is an override.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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