一个导出Excel非常快的类[5]

  FCol := 0;
  if DBGridEh.FooterRowCount = 1 then
  begin
    for i := 0 to DBGridEh.Columns.Count - 1 do
    begin
      if DBGridEh.Columns[i].Visible then
      begin
        WriteStringCell(DBGridEh.Columns[i].Footer.Value,False);
        Inc(FCol);
      end;
    end;
  end
  else if DBGridEh.FooterRowCount > 1 then
  begin
    for i := 0 to DBGridEh.Columns.Count - 1 do
    begin
      if DBGridEh.Columns[i].Visible then
      begin
        for j := 0 to DBGridEh.Columns[i].Footers.Count - 1 do
        begin
          WriteStringCell(DBGridEh.Columns[i].Footers[j].Value ,False);
          Inc(FRow);
        end;
        Inc(FCol);
        FRow := FRow - DBGridEh.Columns[i].Footers.Count;
      end;
    end;
  end;
  FCol := 0;
end;

procedure TDBGridEhToExcel.SaveStream(aStream: TStream);
begin
  FCol := 0;
  FRow := 0;
  Stream := aStream;

  //输出前缀
  WritePrefix;

  //输出表格标题
  WriteHeader;

  //输出列标题
  WriteTitle;

  //输出数据集内容
  WriteDataCell;

  //输出DBGridEh表脚
  WriteFooter;

  //输出后缀
  WriteSuffix;
end;

procedure TDBGridEhToExcel.ExportToExcel;
var
  FileStream: TFileStream;
  Msg: String;
begin
  //如果数据集为空或没有打开则退出
  if (DBGridEh.DataSource.DataSet.IsEmpty) or (not DBGridEh.DataSource.DataSet.Active) then
    exit;

  //如果保存的文件名为空则退出
  if Trim(FileName) = '' then
    exit;
   
  //根据表格修改数据集字段顺序及字段中文标题
  SetDataSetCrossIndexDBGridEh;

  Screen.Cursor := crHourGlass;
  try
    try
      if FileExists(FileName) then
      begin
        Msg := '已存在文件（' + FileName + '），是否覆盖？';
        if Application.MessageBox(PChar(Msg),'提示',MB_YESNO+MB_ICONQUESTION+MB_DEFBUTTON2) = IDYES then
        begin
          //删除文件
          DeleteFile(FileName)
        end
        else
          exit;
      end;

      //显示进度窗体
      if ShowProgress then
        CreateProcessForm(nil);
       
      FileStream := TFileStream.Create(FileName, fmCreate);
      try
        //输出文件
        SaveStream(FileStream);
      finally
        FileStream.Free;
      end;
     
      //打开Excel文件
      ShellExecute(0, 'Open', PChar(FileName), nil, nil, SW_SHOW);
    except

    end;
  finally
    if ShowProgress then
      FreeAndNil(FProgressForm);
    Screen.Cursor := crDefault;
  end;
end;

destructor TDBGridEhToExcel.Destroy;
begin
  inherited Destroy;
end;

procedure TDBGridEhToExcel.CreateProcessForm(AOwner: TComponent);
var
  Panel: TPanel;
  Prompt: TLabel;                                           {提示的标签}
begin
  if Assigned(FProgressForm) then
    exit;