关于Control->Perform(.)解决方案

2012-09-10

关于Control-Perform(...)我看到一段delphi代码如下Delphi(Pascal) codeprocedure DoTrans(Canvas : TCan

关于Control->Perform(...)
我看到一段delphi代码如下

Delphi(Pascal) code

procedure DoTrans(Canvas : TCanvas; Control : TWinControl);var    DC : HDC;    SaveIndex : HDC;    Position: TPoint;begin    if Control.Parent <> nil then    begin{$R-}        DC := Canvas.Handle;        SaveIndex := SaveDC(DC);        GetViewportOrgEx(DC, Position);        SetViewportOrgEx(DC, Position.X - Control.Left, Position.Y - Control.Top, nil);        IntersectClipRect(DC, 0, 0, Control.Parent.ClientWidth, Control.Parent.ClientHeight);        Control.Parent.Perform(WM_ERASEBKGND, DC, 0);        Control.Parent.Perform(WM_PAINT, DC, 0);        RestoreDC(DC, SaveIndex);{$R+}    end;end;

我把它转译成BCB的，这句总是报错，第二个参数类型不匹配
Control->Parent->Perform(WM_ERASEBKGND, DC, 0);
我写成
Control->Parent->Perform(WM_ERASEBKGND, （int）DC, 0);
强制类型转换，编译是通过了，

但是这样写行么？

[解决办法]
Perform原型如下

C/C++ code

int __fastcall Perform(unsigned Msg, int WParam, int LParam);
[解决办法]
强制转换一下类型：
C/C++ codeControl->Parent->Perform(WM_ERASEBKGND, (WPARAM)DC, 0);

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关于Control->Perform(.)解决方案