解决办法：

HttpContext.Current.Response.Clear();HttpContext.Current.Response.Buffer = true;HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");HttpContext.Current.Response.Charset = "gb2312";HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}.xls", string.IsNullOrEmpty(fileName) ? DateTime.Now.ToString("yyyyMMddHHmmssfff") : System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8)));HttpContext.Current.Response.BinaryWrite(ms.ToArray());HttpContext.Current.Response.End();

不过上述方法在firefox上还是乱码

 

终极解决办法：

Encoding encoding;                string outputFileName = null;                string browser = HttpContext.Current.Request.UserAgent.ToUpper();                if (browser.Contains("MS") == true && browser.Contains("IE") == true)                {                    outputFileName = HttpUtility.UrlEncode(fileName);                    encoding = System.Text.Encoding.Default;                }                else if (browser.Contains("FIREFOX") == true)                {                    outputFileName = fileName;                    encoding = System.Text.Encoding.GetEncoding("GB2312");                }                else                {                    outputFileName = HttpUtility.UrlEncode(fileName);                    encoding = System.Text.Encoding.Default;                }                HttpContext.Current.Response.Clear();                HttpContext.Current.Response.Buffer = true;                HttpContext.Current.Response.ContentEncoding = encoding;                HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}.xls", string.IsNullOrEmpty(outputFileName) ? DateTime.Now.ToString("yyyyMMddHHmmssfff") : outputFileName));                HttpContext.Current.Response.BinaryWrite(ms.ToArray());                HttpContext.Current.Response.End();