firemonkey即时将项目添加到HorzScrollBox

问题描述

我的表单上有一个Horizo​​ntal Scroll Box项.运行该程序后，我将得到一个json字符串，其中包含必须在Horizo​​ntal Scroll Box中的项列表，而且我必须动态添加它们.

i have a Horizontal Scroll Box item on my form.after run the program i will get a json string that include the list of items that must be in Horizontal Scroll Box .and i must add them dynamically.

例如我有这个:在运行程序后?区域我必须有新图像.

for example i have this :after run the program in the ? area i must a a new image.

我发现了这个功能:HorzScrollBox1.AddObject();，但为此需要一个参数

i found the function :HorzScrollBox1.AddObject(); but a argument is required for this

我有两个问题:

1)我如何向其中添加新对象?

1)how can i add the new object to this?

2)我可以克隆现有图像并将其添加到列表的末尾吗?

2)can i clone an existing image and add it at the end of the list?

推荐答案

添加对象:有两种方法-设置子级的Parent属性或执行父级的AddObject方法. Parent属性设置器有一些检查，然后调用AddObject.根据控件类，可以将子对象添加到控件的Controls集合或其Content私有字段中.并非所有的类都提供对该字段的访问权限(在某些情况下，您可以使用替代方法，例如这个问题). HorzScrollBox在公共部分具有此字段.

Add object: there are two ways - set Parent property of children or execute AddObject method of parent. Parent property setter has some checks, and call AddObject.Depending on control class, child object can be added to Controls collection of the control or to its Content private field. Not all classes provide access to this field (in some cases you can use workaround, like in this question). HorzScrollBox has this field in public section.

因此，如果要克隆现有图像，则必须:

So, if you want to clone existing image, you must:

1. 从HorzScrollBox的Content

创建新图像并设置其属性

Create new image and set it properties

将新图像放入HorzScrollBox.

Put new image to HorzScrollBox.

例如:

procedure TForm2.btnAddImgClick(Sender: TObject);
  function FindLastImg: TImage;
  var
    i: Integer;
    tmpImage: TImage;
  begin
    Result:=nil;
    // search scroll box content for "most right" image
    for i := 0 to HorzScrollBox1.Content.ControlsCount-1 do
      if HorzScrollBox1.Content.Controls[i] is TImage then
        begin
          tmpImage:=TImage(HorzScrollBox1.Content.Controls[i]);
          if not Assigned(Result) or (Result.BoundsRect.Right < tmpImage.BoundsRect.Right) then
            Result:=tmpImage;
        end;
  end;

  function CloneImage(SourceImage: TImage): TImage;
  var
    NewRect: TRectF;
  begin
    Result:=TImage.Create(SourceImage.Owner);
    Result.Parent:=SourceImage.Parent;

    // Copy needed properties. Assign not work for TImage...
    Result.Align:=SourceImage.Align;
    Result.Opacity:=SourceImage.Opacity;
    Result.MultiResBitmap.Assign(SourceImage.MultiResBitmap);

    // move new image
    NewRect:= SourceImage.BoundsRect;
    NewRect.Offset(NewRect.Width, 0); // move rect to right.
    Result.BoundsRect:=NewRect;
  end;
begin
  CloneImage(FindLastImg);
end;

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