那位大侠给一个上传文件（不需要该名字）并且如果有重复并提示的例子吧！C#的 多谢

客户端上传空间为(*.aspx)：
<INPUT class="TextBoxMain" id="UpLoadPath" style="WIDTH: 350px" type="file" name="File1" runat="server">服务器端(*.aspx.cs):
if(UpLoadPath.PostedFile!=null)
{
if(UpLoadPath.PostedFile.FileName=="")
{
Response.Write("<script>alert('" + this.lblNoFile.Text.Trim() + " ')</script>");
return;
}
else if(UpLoadPath.PostedFile.FileName.EndsWith("txt"))
{
string[] pTemp;
string pFileName =UpLoadPath.PostedFile.FileName;
string pSplit=@"\";
char[] pChar=pSplit.ToCharArray();
pTemp = pFileName.Split(pChar);
pFileName = pTemp[pTemp.Length-1]; pVersion=DateTime.Now.Date.ToString("yyyyMMdd")+DateTime.Now.ToLongTimeString().Replace(":","");
pBomFileNme=pFileName.Replace(".xls","");
//判断在全局配置信息缓冲池中是否存在上传的定位目录信息
//ConfigManager cm=(ConfigManager) Thread.GetDomain().GetData("ConfigManager");
sFilePath=System.Configuration.ConfigurationSettings.AppSettings["BomUploadFilePath"].ToString().Trim();
//pFileName=cm["BomUploadFilePath"].ToString()+pBomFileNme+"_"+pVersion+".xls";
pFileName=sFilePath + sUserName +"_" +pVersion+ "_" + pBomFileNme+".xls";
UpLoadPath.PostedFile.SaveAs(pFileName); BomUploadCollection oC=new BomUploadCollection();
BomUploadController oBomUploadController=new BomUploadController();