我需要在ComboBox的每个项目上添加一个按钮(可能是TSpeedButton？).单击该按钮时,将从列表中删除相应的项目.例如：
我在字符串网格中看到过类似的关于SpeedButtons的讨论(这里：TStringGrid with SpeedButtons),但我不知道如何在ComboBox上实现所有这些东西.能否请您给我一些建议或链接,以便进一步阅读该主题.
解决方法
除了用户体验评论之外,我同意这个问题的解决方案并不是那么难.
您可以通过将Style属性设置为csOwnerDrawFixed,在OnDrawItem事件中自己绘制项目,并在OnSelect事件中删除所选项目来完成此操作,例如,如下所示：
unit Unit1;
interface
uses
Winapi.Windows,System.Classes,Vcl.Controls,Vcl.Forms,Vcl.StdCtrls,Vcl.Imaging.PNGIMage;
type
TForm1 = class(TForm)
ComboBox1: TComboBox;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure ComboBox1DrawItem(Control: TWinControl; Index: Integer;
Rect: TRect; State: TOwnerDrawState);
procedure ComboBox1Select(Sender: TObject);
private
FDeleteGraphic: TPNGImage;
FDeleteRect: TRect;
end;
implementation
{$R *.dfm}
{ TForm1 }
procedure TForm1.ComboBox1DrawItem(Control: TWinControl; Index: Integer;
Rect: TRect; State: TOwnerDrawState);
begin
ComboBox1.Canvas.FillRect(Rect);
if Index >= 0 then
ComboBox1.Canvas.TextOut(Rect.Left + 2,Rect.Top,ComboBox1.Items[Index]);
if (odSelected in State) and not (odComboBoxEdit in State) then
begin
FDeleteRect := Rect;
FDeleteRect.Left := FDeleteRect.Right - FDeleteGraphic.Width;
ComboBox1.Canvas.Draw(FDeleteRect.Left,FDeleteRect.Top,FDeleteGraphic);
end;
end;
procedure TForm1.ComboBox1Select(Sender: TObject);
var
MousePos: TPoint;
begin
MousePos := ComboBox1.ScreenToClient(Mouse.CursorPos);
MousePos.Offset(0,-ComboBox1.Height);
if PtInRect(FDeleteRect,MousePos) then
begin
ComboBox1.Items.Delete(ComboBox1.ItemIndex);
ComboBox1.Invalidate;
end;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
FDeleteGraphic := TPNGImage.Create;
FDeleteGraphic.LoadFromFile('H:\Icons\FamFam Common\Delete.png');
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
FDeleteGraphic.Free;
end;
end.
有了这个结果：
您可能希望(重新)存储先前的ItemIndex设置.根据您的意愿定制.