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Table of Contents
6. Win32 Programming
6.4. Associating a Window Procedure with a Window Class
6.4. Associating a Window Procedure with a
Window Class
One associates a window procedure with a window class when registering the
class. You must fill a TWndClass structure (WIN32.HLP) with information
about the class, and the lpfnWndProc member must specify the address of the
window procedure. To register the class, pass the address of TWndClass
structure to the RegisterClass function (WIN32.HLP). Once the window
class is registered, the window procedure is automatically associated with
each new window created with that class.
The following example shows how to associate the window procedure in the
previous example with a window class:
var
wc: TWndClass;
begin
// Register the main window class.
with wc do begin
style := CS_HREDRAW or CS_VREDRAW;
lpfnWndProc := @MainWndProc;
cbClsExtra := 0;
cbWndExtra := 0;
hInstance := System.hInstance;
hIcon := LoadIcon(THandle(NIL), IDI_APPLICATION);
hCursor := LoadCursor(THandle(NIL), IDC_ARROW);
hbrBackground := GetStockObject(WHITE_BRUSH);
lpszMenuName := 'MainMenu';
lpszClassName := 'MainWindowClass';
end;
if not RegisterClass(wc) then MyError;
// Process other messages.
end.
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