procedure DBGrid1TitleClick(Column: TColumn);
var i:integer;
begin
  if column.Index=0 then begin    //验证是否第一列
    adoquery1.First;                //游标回滚
    DBGrid1.SelectedRows.CurrentRowSelected:=true;    //第一行被选中

    if trim(column.Title.Caption)='全选' then
    begin
      for i:=0 to dbgrid1.DataSource.DataSet.RecordCount-1 do
      begin
        dbgrid1.Fields[0].DataSet.edit;
        dbgrid1.Fields[0].AsBoolean:=true;
        dbgrid1.Fields[0].DataSet.post;
        dbgrid1.datasource.dataset.next;
      end;
      column.Title.Caption:='全消';
    end else begin
      for i:=0 to dbgrid1.DataSource.DataSet.RecordCount-1 do
      begin
        dbgrid1.Fields[0].DataSet.edit;
        dbgrid1.Fields[0].AsBoolean:=false;
        dbgrid1.Fields[0].DataSet.post;
        dbgrid1.datasource.dataset.next;
      end;
      column.Title.Caption:='全选';
    end;
    adoquery1.First;    //游标回滚
    DBGrid1.SelectedRows.CurrentRowSelected:=true;  //选中第一行
  end;
end;