在以下按钮单击事件中实现：
private void btnMIME_Click(object sender, System.EventArgs e)
{
BindData();
Response.ContentType = "application/vnd.ms-excel";
Response.AddHeader("Content-Disposition", "inline;filename="
+ HttpUtility.UrlEncode("下载文件.xls",Encoding.UTF8 ) );

//如果输出为Word，修改为以下代码
//Response.ContentType = "application/ms-word"
//Response.AddHeader("Content-Disposition", "inline;filename=test.doc")
StringBuilder sb=new StringBuilder();
System.IO.StringWriter sw = new System.IO.StringWriter(sb);
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(sw);
sb.Append("");
dgShow.RenderControl(hw);
sb.Append("");
Response.Write(sb.ToString());
Response.End();
}
注：1.若DataGrid中有按钮列，则在导出前应先将其隐藏.
2.若DataGrid有分页，而又要打印所有数据的话就应先取消分页.

来源:网络