//上传器材图片  filename为图片路径
public  void  UpPic(string  filename)  
{  
HttpPostedFile  postedFile=filename;  
string  upfile=System.IO.Path.GetFileName(postedFile.FileName);  
string  fileexten=System.IO.Path.GetExtension(upfile);  
string  newfilename=DateTime.Now.Year.ToString()+DateTime.Now.Month.ToString()+DateTime.Now.Day.ToString()+DateTime.Now.Hour.ToString()+DateTime.Now.Minute.ToString()+DateTime.Now.Second.ToString()+DateTime.Now.Millisecond.ToString()+fileexten;  
postedFile.SaveAs(System.Web.HttpContext.Current.Server.MapPath("../qcpic/")+newfilename);  
}  
 
编译出错   
D:\消防工作资料\消防程序\器材管理\CKAdmin\rk.aspx.cs(264):  无法将类型“string”隐式转换为“System.Web.HttpPostedFile”