(*//
  标题:数据网格自动适应宽度
  说明:使用DBGrid不可不看
  设计:Zswang
  日期:2002-03-04
  支持:wjhu111@21cn.com
  //*)

  ///////Begin   Source
  uses
      Math;

  function   DBGridRecordSize(mColumn:   TColumn):   Boolean;
  {   返回记录数据网格列显示最大宽度是否成功   }
  begin
      Result   :=   False;
      if   not   Assigned(mColumn.Field)   then   Exit;
      mColumn.Field.Tag   :=   Max(mColumn.Field.Tag,
          TDBGrid(mColumn.Grid).Canvas.TextWidth(mColumn.Field.DisplayText));
      Result   :=   True;
  end;   {   DBGridRecordSize   }

  function   DBGridAutoSize(mDBGrid:   TDBGrid;   mOffset:   Integer   =   5):   Boolean;
  {   返回数据网格自动适应宽度是否成功   }
  var
      I:   Integer;
  begin
      Result   :=   False;
      if   not   Assigned(mDBGrid)   then   Exit;
      if   not   Assigned(mDBGrid.DataSource)   then   Exit;
      if   not   Assigned(mDBGrid.DataSource.DataSet)   then   Exit;
      if   not   mDBGrid.DataSource.DataSet.Active   then   Exit;
      for   I   :=   0   to   mDBGrid.Columns.Count   -   1   do   begin
          if   not   mDBGrid.Columns[I].Visible   then   Continue;
          if   Assigned(mDBGrid.Columns[I].Field)   then
              mDBGrid.Columns[I].Width   :=   Max(mDBGrid.Columns[I].Field.Tag,
                  mDBGrid.Canvas.TextWidth(mDBGrid.Columns[I].Title.Caption))   +   mOffset
          else   mDBGrid.Columns[I].Width   :=
              mDBGrid.Canvas.TextWidth(mDBGrid.Columns[I].Title.Caption)   +   mOffset;
          mDBGrid.Refresh;
      end;
      Result   :=   True;
  end;   {   DBGridAutoSize   }
  ///////End   Source

  ///////Begin   Demo
  procedure   TForm1.DBGrid1DrawColumnCell(Sender:   TObject;   const   Rect:   TRect;
      DataCol:   Integer;   Column:   TColumn;   State:   TGridDrawState);
  begin
      DBGridRecordSize(Column);
  end;

  procedure   TForm1.Button2Click(Sender:   TObject);
  begin
      DBGridAutoSize(DBGrid1);
  end;
  ///////End   Demo