enlib中DBGRIGEH如何导出各种文件

 strdate:=FormatdateTime('ddddd',Now);
  SaveDialog1.FileName := '客户基本信息表'+strdate;
   if SaveDialog1.Execute then
    begin
      case SaveDialog1.FilterIndex of
        1: begin ExpClass := TDBGridEhExportAsXLS; Ext := 'xls'; end;
        2: begin ExpClass := TDBGridEhExportAsText; Ext := 'txt'; end;
        3: begin ExpClass := TDBGridEhExportAsCSV; Ext := 'csv'; end;
        4: begin ExpClass := TDBGridEhExportAsHTML; Ext := 'html'; end;
        5: begin ExpClass := TDBGridEhExportAsRTF; Ext := 'rtf'; end;

      else
        ExpClass := nil; Ext := '';
      end;
      if ExpClass <> nil then
      begin
        if UpperCase(Copy(SaveDialog1.FileName,Length(SaveDialog1.FileName)-2,3)) <>
           UpperCase(Ext) then
          SaveDialog1.FileName := SaveDialog1.FileName + '.' + ext;
        SaveDBGridEhToExportFile(ExpClass,dbgrideh1,
             SaveDialog1.FileName,true);
     end;
   end;