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

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

int __fastcall Perform(unsigned Msg, int WParam, int LParam);

可见是可以的
[解决办法]
强制转换一下类型：

Control->Parent->Perform(WM_ERASEBKGND, (WPARAM)DC, 0);