一个BCB中关于画布Canvas方面的问题
我用这个代码显示“新春快乐，万事如意”：
Canvas->Font->Size=20;
Canvas->Font->Name="隶书";
Canvas->Font->Color=clRed;
Canvas->Brush->Color=clGreen;
Canvas->TextOut(20,30,"新春快乐，万事如意")；

如果让这行文字消失，代码要怎么写啊

[解决办法]
你这些代码是卸载 OnPaint 里的么
[解决办法]
你这些代码是写在 OnPaint 里的么
[解决办法]

void __fastcall TForm1::FormPaint(TObject *Sender)
{
    Canvas->Font->Size=20;
    Canvas->Font->Name="隶书";
    Canvas->Font->Color=clRed;
    Canvas->Brush->Color=clGreen;
    TRect r = Rect(20,30,20+Canvas->TextWidth(txt), 30+Canvas->TextHeight(txt));
    Canvas->FillRect(r);
    Canvas->TextOut(r.left,r.top,txt);
}
// 显示另一句话
void __fastcall TForm1::btn1Click(TObject *Sender)
{
    txt = "新春快乐，万事如意";
    Repaint();
}

// 擦掉
void __fastcall TForm1::btn2Click(TObject *Sender)
{
    txt = "";
    Repaint();
}
// 显示另一句话
void __fastcall TForm1::btn3Click(TObject *Sender)
{
    txt = "元旦快乐，万事胜意";
    Repaint();
}

[解决办法]
用一个全局变量 String txt;
[解决办法]
这两行可以去掉，如果你不考虑保留背景色的话
//TRect r = Rect(20,30,20+Canvas->TextWidth(txt), 30+Canvas->TextHeight(txt));
//Canvas->FillRect(r);

直接这样就可以了 Canvas->TextOut(20,30,txt);