如何在返回到前一个位置时避免TDbgrid滚动 [英] How to avoid TDbgrid scrolling when returning to a previous location

问题描述

在下面的代码中，我们对某些选定的行执行一些操作（而不是删除）。

In the code below, we do some operations (not deletions) on some selected rows.

但是，有时候，完成后，顶部选中的行已滚动它以网格的1/2方式显示。有没有办法避免这种滚动？ （如果我的代码遍历下面选择的行是不正确的，因为一些无关的原因，我欢迎更正。）

However, sometimes, when finished, the top selected row has scrolled so that it is displayed 1/2 way down the grid. Is there a way to avoid this scrolling? (If my code to traverse the selected row below is improper for some unrelated reason, I welcome corrections.)

  Function TForm.DoSomethingToSelectedRows;
  var
    KeyAtStart: Integer;
  begin
    Result := TRUE;
    KeyAtStart := DataSet.FieldByName('Key').AsInteger;
    DataSet.DisableControls;
    DataSet.First;
    try
      while Result AND (NOT DataSet.EOF) do  DataSet
        begin
          if DBGrid1.SelectedRows.CurrentRowSelected then
            Result := ... do something ...
          fMPODataTls.GetDS.Next;
        end;
    finally
      DataSet.Locate('Key', KeyAtStart, []);    // re-position where we started
      DataSet.EnableControls;
    end;
  end;

推荐答案

循环访问数据集之前，可以记下网格显示的顶行和显示的总记录数。有了这些信息，在您重新定位记录后，您可以将记录移动到顶部或底部，然后再次移动，将记录定位到确切的行。

Before looping through the dataset, you can keep note of the top row that the grid is displaying and the number of total records that is displayed. With this information, after you relocate the record, you can position the record to the exact row by moving either to the top or to the bottom and then moving back again.

您可以通过 MoveBy 执行移动。不幸的是，行和 RowCount 属性 TDBGrid 被保护，因为你必须使用所谓的受保护的黑客。

You can carry out the moving by MoveBys. Unfortunately the Row and RowCount properties of TDBGrid is protected, for that you have to use what is widely known as 'protected hack'.

在这个的答案，连同检查书签，以便你不会记录错误。

There's code example in this answer, together with checking bookmarks, so that you don't end up on a wrong record.

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