刷新dbgrid 而不失去当前行位置

我们有一个Delphi的数据库应用程序,上面有个DBGrid和一个数据集:

DBGrid是用来显示来自数据集(查询或表)的数据,根据设计,当您调用已经打开的数据集的Refresh方

法(例如使用DBNavigator的Refresh),当前行的位置将被设置为0 (第一个记录)。

这意味着,如果用户选择了DBGrid的底部某个地方的一行记录,在刷新后,当前激活的行将改为第一行:

(

如果你一直在问:“有什么办法重新查询或刷新后,让TDBGrid中的数据留在准确位置(不改变位置)?

”这里的一个答案的问题:

刷新DBGrid的数据 - 保留行的位置
这里的一个小程序控制刷新DBGrid的内容后不会失去该行的位置。

//THackDBGrid = class(TDBGrid)
 
 //refresh datagrid data - preserve rowposition
 procedure Refresh_PreservePosition;
 var
   rowDelta: Integer;
   row: integer;
   recNo: integer;
   ds : TDataSet;
 begin
   ds :=THackDBGrid(DBGrid1).DataSource.DataSet;
 
   rowDelta := -1 +THackDBGrid(DBGrid1).Row;
   row := ds.RecNo;
 
   ds.Refresh;
 
   with ds do
   begin
    DisableControls;
    RecNo := row;
    MoveBy(-rowDelta) ;
    MoveBy(rowDelta) ;
    EnableControls;
   end;
 end;

请注意这里使用的保护破解(THackDBGrid)来获得隐藏的(protected)Row属性!

英文原文

There's DBGrid, there's adataset and we have a data awareDelphi application :)

When DBGrid is used to display data from a dataset (query ortable), by design, after you call Refresh method on a dataset(re-open) (for example, using a DBNavigator), the current row position will be setto zero (first record).

This means that if a user has selected a row somewhere near thebottom of a DBGrid, after a Refresh, the active row will be changedto first row :(

If you have been asking "Is there any way to reopen or refresh aquery, leaving the TDBGrid data exactly where it is (withoutchanging the positions)?" Here's one answer to the problem:

Refresh DBGrid Data - Preserve Row Position

Here's a handly little procedure to refresh the content of aDBGrid without losing the row position.

  1.  
    //THackDBGrid = class(TDBGrid)
  2.  
     
  3.  
    //refresh datagrid data - preserve row position
  4.  
    procedure Refresh_PreservePosition;
  5.  
    var
  6.  
      rowDelta: Integer;
  7.  
      row: integer;
  8.  
      recNo: integer;
  9.  
      ds : TDataSet;
  10.  
    begin
  11.  
      ds := THackDBGrid(DBGrid1).DataSource.DataSet;
  12.  
     
  13.  
      rowDelta := -1 + THackDBGrid(DBGrid1).Row;
  14.  
      row := ds.RecNo;
  15.  
     
  16.  
      ds.Refresh;
  17.  
     
  18.  
      with ds do
  19.  
      begin
  20.  
        DisableControls;
  21.  
        RecNo := row;
  22.  
        MoveBy(-rowDelta) ;
  23.  
        MoveBy(rowDelta) ;
  24.  
        EnableControls;
  25.  
      end;
  26.  
    end;
  27.  
     

Note the protected hack used here(THackDBGrid) to get the hidden (protected) Row property!

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