如何禁用 TScrollBox 的滚动视图行为? [英] How can I disable the scroll-into-view behavior of TScrollBox?

问题描述

我有一个 TScrollBox，它有一个比滚动框大的 RichEdit，所以两个侧滚动条都出现在滚动框中.然后我有一个函数 DoTask 调用 RichEdit.SetFocus.

I have a TScrollBox that has a RichEdit that is bigger than the scrollbox, so both side scrollbars appear in the scrollbox. Then I have a function DoTask that calls RichEdit.SetFocus.

当我向下滚动到我想看到部分文本控件的地方，然后调用DoTask时，ScrollBox会自动滚动到RichEdit的顶部.我怎样才能避免这种情况?

When I scroll down to where I want to see part of the text control, and then call DoTask, the ScrollBox will automatically scroll to the top of the RichEdit. How can I avoid that?

推荐答案

如您所愿，这里有一些建议:

As you wish, here are some suggestions:

• 以以下形式覆盖SetFocusedControl:

function TForm1.SetFocusedControl(Control: TWinControl): Boolean;
begin
  if Control = RichEdit then
    Result := True
  else
    Result := inherited SetFocusedControl(Control);
end;

或者:

type
  TCustomMemoAccess = class(TCustomMemo);

function TForm1.SetFocusedControl(Control: TWinControl): Boolean;
var
  Memo: TCustomMemoAccess;
  Scroller: TScrollingWinControl;
  Pt: TPoint;
begin
  Result := inherited SetFocusedControl(Control);
  if (Control is TCustomMemo) and (Control.Parent <> nil) and
    (Control.Parent is TScrollingWinControl) then
  begin
    Memo := TCustomMemoAccess(Control);
    Scroller := TScrollingWinControl(Memo.Parent);
    SendMessage(Memo.Handle, EM_POSFROMCHAR, Integer(@Pt), Memo.SelStart);
    Scroller.VertScrollBar.Position := Scroller.VertScrollBar.Position +
      Memo.Top + Pt.Y;
  end;
end;

插入TScrollBox:

type
  TScrollBox = class(Forms.TScrollBox)
  protected
    procedure AutoScrollInView(AControl: TControl); override;
  end;

procedure TScrollBox.AutoScrollInView(AControl: TControl);
begin
  if not (AControl is TCustomMemo) then
    inherited AutoScrollInView(AControl);
end;

或者:

procedure TScrollBox.AutoScrollInView(AControl: TControl);
begin
  if (AControl.Top > VertScrollBar.Position + ClientHeight) xor
      (AControl.Top + AControl.Height < VertScrollBar.Position) then
    inherited AutoScrollInView(AControl);
end;

或者使用上述所有内容的任意创意组合.您喜欢滚动的方式和时间只有您自己知道.

Or use any creative combination of all of the above. How and when you like it to be scrolled only you know.

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