Try this code:
<asp:fileupload id="issueCommentFileUpload" runat="server" xmlns:asp="#unknown" />
string issuefileName = string.Empty;
if (issueCommentFileUpload.HasFile)
try
{
issuefileName = issueCommentFileUpload.FileName;
string destinationPath = Server.MapPath("./Upload/" + issuefileName);
issueCommentFileUpload.SaveAs(destinationPath);
}
catch (Exception exObj)
{
Response.Write("Some thing wrong");
log.Error("GetIncedencePrimaryInfo method Sql Error : " + exObj.Message.ToString());
}