asp.net 程序，当发生找不到文件的错误时，如何正确定位是哪个文件？

需要在Global.asax.cs中添加Application_Error代码如下，在Log中查看是哪个文件缺失：

protected void Application_Error(object sender, EventArgs e)
        {
            // Code that runs when an unhandled error occurs

            // Get the exception object.
            Exception exc = Server.GetLastError();

            if (exc.Message == "File does not exist." || exc.Message == "文件不存在。")
            {
                throw new Exception(string.Format("{0} {1}", exc.Message, HttpContext.Current.Request.Url.ToString()), exc);
            }

            // Handle HTTP errors
            if (exc.GetType() == typeof(HttpException))
            {
                // The Complete Error Handling Example generates
                // some errors using URLs with "NoCatch" in them;
                // ignore these here to simulate what would happen
                // if a global.asax handler were not implemented.
                if (exc.Message.Contains("NoCatch") || exc.Message.Contains("maxUrlLength"))
                    return;

                //Redirect HTTP errors to HttpError page
                Server.Transfer("/Pages/CustomErrorPage.htm");
            }

            // Log the exception and notify system operators
            _log.Error(exc);

            // Clear the error from the server
            //Server.ClearError();
        }