重写对话框类

在妖哥的提示下继承TCustomForm来创建新的对话框。我原来的对话是将一个TForm包含在DLL调用，虽然也达到想要的效果，但是工作量很大。这个dll就有500多K，现在写成一个类，相对来说，就是轻量级的。配合GDI函数自绘，模拟win8对话框效果。

#ifndef __TFORMCONTROL__
#define __TFORMCONTROL__
#include "gdi.h"

class TFormControl :public TCustomForm
{
    private:
       int m_left;
       int m_top;
       int m_width;
       int m_height;
       TRect m_enter_rect; //确定按钮位置区域
       TRect m_cancel_rect;//取消按钮位置区域
       TRect m_close_rect; //关闭按钮位置区域
       TRect m_ok_rect;    //OK按钮位置区域
       TRect m_form_rect;

       unsigned int m_out_rectangle_color; //外边框
       unsigned int m_in_rectangle_color;  //内边框

       bool m_mouse_move_close;            //鼠标在关闭按钮上
       bool m_mouse_move_enter;            //鼠标是否在确定按钮上

       Graphics::TBitmap * background_bmp;
       Graphics::TBitmap * foreground_bmp;

       AnsiString m_caption;    //窗口标题
       AnsiString m_text;
       AnsiString m_icon_png;   //小图标名称
    protected:
        void Draw();
        void DrawCloseBox(bool value);     //画关闭按钮
        void DrawEnterBox(bool value);     //画确定按钮
        void DrawCaption(AnsiString value);//画标题
        void DrawText(AnsiString value);   //画文本
        void DrawIcon(AnsiString value);   //画图标

        void SetText(AnsiString value);    //设置文本
        void SetIcon(AnsiString value);    //设置图标
        void SetCaption(AnsiString value); //设置标题

        void UpdateBackground(int width,int hegiht);          //更新背景
    public:
        __fastcall virtual TFormControl(TComponent * AOwner):TCustomForm(AOwner){};
        __fastcall virtual TFormControl(TComponent * AOwner,int Dummy);
        DYNAMIC void __fastcall Paint(void);

       	DYNAMIC void __fastcall MouseDown(TMouseButton Button, Classes::TShiftState Shift, int X, int Y);
	DYNAMIC void __fastcall MouseMove(Classes::TShiftState Shift, int X, int Y);
	DYNAMIC void __fastcall MouseUp(TMouseButton Button, Classes::TShiftState Shift, int X, int Y);

        __property Font;
        __property AnsiString Text={read = m_text,write=SetText};
        __property AnsiString Icon={read=m_icon_png,write= SetIcon};
        __property AnsiString Tip ={read=m_caption,write=SetCaption};
};
__fastcall TFormControl::TFormControl(TComponent * AOwner,int Dummy):TCustomForm(AOwner,Dummy)
{
     TScreen * s = new TScreen(this);

     m_form_rect.left = 0;
     m_form_rect.top  = 0;
     m_form_rect.right = 450;
     m_form_rect.bottom= 200;

     this->BorderStyle = bsNone;

     this->Left  = s->Width/2-m_form_rect.Width()/2;
     this->Top   = s->Height/2-m_form_rect.Height()/2;
     this->Width = m_form_rect.Width();
     this->Height= m_form_rect.Height();

     m_left  = this->Left;
     m_top   = this->Top;
     m_width = this->Width;
     m_height=this->Height;

     //---------------------------------
     m_close_rect.left   = m_width - 8-40;
     m_close_rect.top    = 0;
     m_close_rect.right  = m_width - 9;
     m_close_rect.Bottom = 20;
     //---------------------------------
     m_out_rectangle_color = 0xff6BADF7;
     m_in_rectangle_color  = 0xffF0F0F0;
     //---------------------------------
     m_enter_rect.left  = m_form_rect.Width()/2 - 100/2;//确的按钮宽100
     m_enter_rect.top   = 150;
     m_enter_rect.Right = m_form_rect.Width()/2 + 100/2;
     m_enter_rect.bottom= 175;
     //---------------------------------------------------------
     m_caption = "对话框";
     Font->Name = "微软雅黑";
     Font->Size = 10;
     m_icon_png = "icon.png";
     //---------------------------------------------------------
     background_bmp = new Graphics::TBitmap;
     background_bmp->Width = this->Width;
     background_bmp->Height= this->Height;

     foreground_bmp = new Graphics::TBitmap;
     foreground_bmp->Width = this->Width;
     foreground_bmp->Height= this->Height;
     //----------------------------------------------------------
     GdiInit();
     //----------------------------------------------------------
     UpdateBackground(m_width,m_height);

     GdiReleaseGraphics();

     Draw();
}
void TFormControl::Draw()
{
     foreground_bmp->Assign(background_bmp);

     GdiCreateHandle1(foreground_bmp->Canvas->Handle);
     //----------------------------------------------------------
     //关闭按钮
     DrawCloseBox(m_mouse_move_close);
     //确认按钮
     DrawEnterBox(m_mouse_move_enter);
     //画标题
     DrawCaption(m_caption);
     //画文字
     DrawTextA(m_text);
     //画图标
     DrawIcon(m_icon_png);
     //----------------------------------------------------------
     
     GdiReleaseGraphics();
}
void __fastcall TFormControl::Paint(void)
{
     TRect a(0,0,m_width,m_height);
     this->Canvas->CopyRect(a,foreground_bmp->Canvas,a);
}
void TFormControl::DrawCloseBox(bool value)
{
     if(value)
     {
         foreground_bmp->Canvas->Brush->Color = 0x5050C7;
         foreground_bmp->Canvas->FillRect(m_close_rect);

         //画交叉线
         foreground_bmp->Canvas->Pen->Color = clWhite;
         foreground_bmp->Canvas->Pen->Width = 2;
         foreground_bmp->Canvas->MoveTo(m_close_rect.left+15,m_close_rect.top+5);
         foreground_bmp->Canvas->LineTo(m_close_rect.right-14,15);

         foreground_bmp->Canvas->MoveTo(m_close_rect.left+25,m_close_rect.top+5);
         foreground_bmp->Canvas->LineTo(m_close_rect.left+15,15);
     }
     else
     {
         foreground_bmp->Canvas->Brush->Color = 0xF7AD6B;
         foreground_bmp->Canvas->FillRect(m_close_rect);

         //画交叉线
         foreground_bmp->Canvas->Pen->Color = clWhite;
         foreground_bmp->Canvas->Pen->Width = 2;
         foreground_bmp->Canvas->MoveTo(m_close_rect.left+15,m_close_rect.top+5);
         foreground_bmp->Canvas->LineTo(m_close_rect.right-14,15);

         foreground_bmp->Canvas->MoveTo(m_close_rect.left+25,m_close_rect.top+5);
         foreground_bmp->Canvas->LineTo(m_close_rect.left+15,15);
     }
}
void __fastcall TFormControl::MouseDown(TMouseButton Button, Classes::TShiftState Shift, int X, int Y)
{
   //关闭按钮被点击
   if(m_mouse_move_close)
     this->Close();
   //确定按钮被点击
   if(m_mouse_move_enter)
     this->Close();
}
void __fastcall TFormControl::MouseMove(Classes::TShiftState Shift, int X, int Y)
{
   //判断是否在关闭区域
   bool re = PtInRect(m_close_rect,TPoint(X,Y));
   if(re)
      m_mouse_move_close = true;
   else
      m_mouse_move_close = false;
   //判断是否点击确的按钮
   re = PtInRect(m_enter_rect,TPoint(X,Y));
   if(re)
      m_mouse_move_enter = true;
   else
      m_mouse_move_enter = false;

   DrawText(m_text);
   //重绘图形并显示
   Draw();
   Paint();
}
void __fastcall TFormControl::MouseUp(TMouseButton Button, Classes::TShiftState Shift, int X, int Y)
{

}
void TFormControl::DrawEnterBox(bool value)
{
   if(value)
     foreground_bmp->Canvas->Pen->Color   = 0xF7AD6B; //鼠标在确定按钮上
   else
     foreground_bmp->Canvas->Pen->Color   = 0xACACAC;

   foreground_bmp->Canvas->Brush->Color   = 0xEAEAEA;
   foreground_bmp->Canvas->Pen->Width     = 1;
   
   foreground_bmp->Canvas->FillRect(m_enter_rect);
   foreground_bmp->Canvas->Rectangle(m_enter_rect);

   foreground_bmp->Canvas->Font->Assign(Font);
   
   long w = foreground_bmp->Canvas->TextWidth("确定");
   long h = foreground_bmp->Canvas->TextHeight("确定")+2;


   foreground_bmp->Canvas->TextOutA(m_enter_rect.left+m_enter_rect.Width()/2-w/2,m_enter_rect.top+m_enter_rect.Height()/2-h/2,"确定");
}
void TFormControl::DrawCaption(AnsiString value)
{
   //标题位置
   int w = foreground_bmp->Canvas->TextWidth(value);
   int m_l = m_width/2-w/2;
   int m_t = 6;

   foreground_bmp->Canvas->Font->Assign(Font);
   foreground_bmp->Canvas->Brush->Style = bsClear;
   foreground_bmp->Canvas->Font->Color = clBlack;
   foreground_bmp->Canvas->TextOutA(m_l,m_t,m_caption);
}
void TFormControl::DrawText(AnsiString value)
{
   foreground_bmp->Canvas->Font->Assign(Font);
   foreground_bmp->Canvas->Brush->Style = bsClear;
   foreground_bmp->Canvas->Font->Color = clBlack;
   foreground_bmp->Canvas->TextOutA(100,70,m_text);

}
void TFormControl::SetText(AnsiString value)
{
   m_text = value;
   int w = foreground_bmp->Canvas->TextWidth(value);
   this->Width = w+200;
   m_width = w+200;
   UpdateBackground(m_width,m_height);

   Draw();
   Paint();
}
void TFormControl::SetIcon(AnsiString value)
{
   m_icon_png = value;
   Draw();
   Paint();
}
void TFormControl::DrawIcon(AnsiString value)
{
     if(FileExists(value))
     {
        GdiDrawImage(value,30,70,40,40);
     }
}
void TFormControl::SetCaption(AnsiString value)
{
    m_caption = value;
    Draw();
    Paint();
}
void TFormControl::UpdateBackground(int width,int height)
{
    background_bmp->Width = width;
    background_bmp->Height= height;
    foreground_bmp->Width = width;
    foreground_bmp->Height= height;
    //---------------------------------------------------------
    GdiCreateHandle1(background_bmp->Canvas->Handle);
    GdiFillRectSolidBrush(m_out_rectangle_color,0,0,m_width,m_height);//外框
    GdiFillRectSolidBrush(m_in_rectangle_color,7,30,m_width-16,m_height-37);//内矩形
    //----------------------------------------------------------
    GdiPen(0xff53A7B4,1);
    GdiDrawRectangle(0,0,m_width-2,m_height-2);    //外框线
    GdiDrawRectangle(7,30,m_width-16,m_height-37); //内框线
    //----------------------------------------------------------
    //确定按钮位置更新
    m_enter_rect.left  = m_width/2 - 100/2;//确的按钮宽100
    m_enter_rect.top   = 150;
    m_enter_rect.Right = m_width/2 + 100/2;
    m_enter_rect.bottom= 175;
    //关闭按钮位置更新
    m_close_rect.left   = m_width - 8-40;
    m_close_rect.top    = 0;
    m_close_rect.right  = m_width - 9;
    m_close_rect.Bottom = 20;
}
//类似vcl风格的调用对话框函数
long  ShowMessageBox(TForm * f,AnsiString str,AnsiString tip,AnsiString icon)
{
    TFormControl * dialog = new TFormControl(f,0);
    dialog->Text = str;
    dialog->Tip  = tip;
    dialog->Icon = icon;
    dialog->ShowModal();
    delete dialog;
}

#endif
 调用方法如下：
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    ShowMessageBox(this,"请选择您的设备型号","设备型号","icon.png");  
}

显示如下图：