通过继承实现不同的CheckBox风格

VCL中的TCheckBox控件在选中时显示的是一个“√”，但有的时候需要显示为“×”，下面这段代码是cker写的，实现了这个效果。

// 通过继续实现不同的CheckBox风格

// 代码作者：cker

//---------------------------------------------------------------------------

class TXCheckBox : public TCustomControl

{

private:

bool FDown;

TCheckBoxState FState;

bool FFocused;

TColor FCheckColor;

public:

__fastcall TXCheckBox(TComponent* AOwner);

protected:

void __fastcall Paint();

DYNAMIC void __fastcall MouseDown(TMouseButton Button, TShiftState Shift, int X, int Y);

DYNAMIC void __fastcall MouseUp(TMouseButton Button, TShiftState Shift, int X, int Y);

DYNAMIC void __fastcall MouseMove(TShiftState Shift, int X, int Y);

DYNAMIC void __fastcall KeyDown(Word &Key, TShiftState Shift);

DYNAMIC void __fastcall KeyUp(Word &Key, TShiftState Shift);

void __fastcall SetDown(bool Value);

void __fastcall SetState(TCheckBoxState Value);

void __fastcall SetChecked(bool Value);

bool __fastcall GetChecked();

void __fastcall SetCheckColor(TColor Value);

void __fastcall SetCaption(const TCaption& Value);

TCaption __fastcall GetCaption();

DYNAMIC void __fastcall DoEnter(void);

DYNAMIC void __fastcall DoExit(void);

__published:

__property TCaption Caption = {read=GetCaption, write=SetCaption};

__property TColor CheckColor = {read=FCheckColor, write=SetCheckColor, default=clBlack};

__property bool Checked = {read=GetChecked, write=SetChecked, default=false};

__property bool Down = {read=FDown, write=SetDown, default=false};

__property DragCursor;

__property DragMode;

__property Enabled;

__property Font;

__property ParentFont;

__property PopupMenu;

__property ShowHint;

__property TCheckBoxState State = {read=FState, write=SetState, default=cbUnchecked};

__property TabOrder;

__property TabStop;

__property OnClick;

__property OnDragDrop;

__property OnDragOver;

__property OnEndDrag;

__property OnKeyDown;

__property OnKeyPress;

__property OnKeyUp;

__property OnMouseDown;

__property OnMouseMove;

__property OnMouseUp;

};

__fastcall TXCheckBox::TXCheckBox(TComponent* AOwner):TCustomControl(AOwner)

{

Width = 200;

Height = 20;

ParentColor = false;

Color = clBTnFace;

}

void __fastcall TXCheckBox::Paint()

{

const int BW = 12;

int BL, BT, BR, BB;

int TX, TY, TW, TH;

TRect Rect;

Canvas->Font = Font;

BT = (Height / 2)-(BW / 2);

BB = BT + BW;

BL = 1;

BR = BW + 1;

Canvas->Brush->Color = FDown ? clBtnFace : clWhite;

Canvas->Pen->Width = 1;

Canvas->Pen->Color = clBtnFace;

Canvas->Rectangle(BL, BT, BR, BB);

Canvas->Pen->Color = clBtnShadow;

Canvas->MoveTo(BL, BB);

Canvas->LineTo(BL, BT);

Canvas->Line