Question:
I have a RichEdit control in my COM Server application that uses the tmFree threading model for COM objects, and the RichEdit control is not being created. How can I get around this?
Answer:
This is related to a bug in the VCL for Delphi 5 and you can click here to read more about it. (It is also mentioned in the readme file for Delphi 5).
One possible workaround given was to override CreateParams for a TRichEdit and add the ES_EX_NOCALLOLEINIT style to it. However, this may not always work. Another possible solution is to capture the WM_NCCREATE message and set the proper params at that point. Below is a component that will do that for you.
Download FixedRichEdit.pas
| Sample Code |
unit FixedRichEdit;
interface
uses
Windows, Messages, Classes, Controls, RichEdit, ComCtrls;
type
TFixedRichEdit = class(TRichEdit)
protected
procedure WMNCCreate(var message: TWMNCCreate); message WM_NCCREATE;
end;
procedure Register;
implementation
procedure TFixedRichEdit.WMNCCreate(var message: TWMNCCreate);
var
gwlEx : Longint;
begin
gwlEx := GetWindowLong(WindowHandle, GWL_EXSTYLE);
gwlEx := gwlEx or ES_EX_NOCALLOLEINIT;
message.CreateStruct^.dwExStyle := gwlEx;
inherited;
end;
procedure Register;
begin
RegisterComponents('Samples', [TFixedRichEdit]);
end;
end.
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Last Modified: 05-APR-00