delphi – 为自定义组件创建样式的正确方法

问题1.我可以在组件中嵌入默认样式吗？

是的,您将要与组件一起分发的默认样式嵌入到RT_RCDATA类型的资源中.然后只需将该资源包含在源中：

{$R *.res}

注意：如果在布局编辑器中创建外部对象(TLayout)之前将其放入res中,则需要将其删除.

然后重写GetStyleObject方法以从资源加载样式.

function TLFButton.GetStyleObject: TControl;
var
  S: TResourceStream;
  obj: TLayout;
const
  Style = 'LFButtonStyle';
begin
  result := inherited GetStyleObject;
  if FStyleLookup = 'cornerbuttonstyle' then
  begin
    if FindResource(HInstance,PChar(Style),RT_RCDATA) <> 0 then
    begin
      S := TResourceStream.Create(HInstance,Style,RT_RCDATA);
      try
        obj := TLayout(TStyleManager.LoadFromResource(HInstance,RT_RCDATA));
        //obj := TLayout( CreateObjectFromStream(nil,S) ); << XE2 version
        Result.AddObject(obj);
        Exit;
      finally
        S.Free;
      end;
    end;
  end;
end;

问题2：如何将其与默认样式合并.

在我的例子中,我的组件的基础是TCornerButton.我修剪了我的.style文件,以便它只有我想要的额外位的代码.在这种情况下,一个小三角形表示一个下拉按钮,一行用于分割按钮：

object TLayout
  Align = alRight
  Position.Point = '(76,0)'
  Locked = True
  Width = 15.000000000000000000
  Height = 24.000000000000000000
  object TPath
    StyleName = 'dropdownbutton'
    Align = alCenter
    Position.Point = '(4,9)'
    Width = 8.000000000000000000
    Height = 5.000000000000000000
    HitTest = False
    Fill.Color = claBlack
    Stroke.Kind = bkNone
    Data.Path = {
      04000000000000000000000000000000010000000000803F0000000001000000
      0000003F0000803F030000000000000000000000}
  end
  object TLine
    StyleName = 'dropdownsplit'
    Align = alLeft
    Width = 1.000000000000000000
    Height = 24.000000000000000000
    HitTest = False
    LineType = ltLeft
  end
end

我以完全相同的方式将它放入资源中.

在我的构造函数中,我将StyleLookup设置为“cornerbuttonstyle”

constructor TLFButton.Create(AOwner: TComponent);
begin
  FStyleLookup := 'cornerbuttonstyle';
  FDropDownButton := false;
  inherited;
end;

然后我更改GetStyleObject,以便它加载新的东西并将其添加到现有样式.

function TLFButton.GetStyleObject: TControl;
var
  S: TResourceStream;
  obj: TLayout;
const
  Style = 'LFButtonStyle';
begin
  result := inherited GetStyleObject;
  if FStyleLookup = 'cornerbuttonstyle' then
  begin
    if FindRCData(HInstance,Style) then
    begin
      S := TResourceStream.Create(HInstance,RT_RCDATA);
      try
        obj := TLayout( CreateObjectFromStream(nil,S) );
        Result.AddObject(obj);
        Exit;
      finally
        S.Free;
      end;
    end;
  end;
end;

我希望这有助于其他人,我发现这一切都非常难以获得信息.

马丁