How to ignore logging errors for images in global asax

Question

I have an error handler in my global.asax as follows;

  Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)
        ' Code that runs when an unhandled error occurs
        Dim ex = Server.GetLastError.GetBaseException
        Dim lastErrorWrapper As HttpException = Server.GetLastError()
        Dim lastError As Exception = lastErrorWrapper

        If lastErrorWrapper.InnerException IsNot Nothing Then
            lastError = lastErrorWrapper.InnerException
        End If

        My.ErrorHandler.LogError( _
            "<BR/><BR/>URL: " & Request.RawUrl & _
            "<BR/><BR/>STACK: " & ex.StackTrace & _
            "<BR/><BR/>SOURCE: " & ex.Source & _
            "<BR/><BR/>MESSAGE: " & ex.Message & _
            "<BR/><BR/>TYPENAME: " & ex.GetType.ToString & _
            "<BR/><BR/>INNER EXCEPTION: " & lastError.ToString & _
            "<BR/><BR/>REFERRER: " & HttpContext.Current.Request.Url.AbsoluteUri & _
            "<BR/><BR/>USER IP: " & Request.ServerVariables("REMOTE_ADDR") & " -- " & Request.ServerVariables("HTTP_USER_AGENT"))
    End Sub

Obviously, this works great and sends me an email whenever there is an error. But, this is also true for any images that are not found in the file system. It gives me a "File does not exist." error. Is there a way to ignore logging errors for images that are not located on disk?

Answer 1

Cant you resolve the FileNotFoundException instead? If the exception should not occur then rather resolve the issue than suppressing it. To handle a known exception you can use the following code.

if(Server.GetLastError().GetBaseException() is System.Web.HttpException)
{
     //You could check whether the 
     //Server.GetLastError().GetBaseException().Message contains the appropriate message
     Debug.WriteLine("Suppressed FileNotFoundException");
}else
//Log an unhandled exception

Answer 2

var ex = Context.Error;

if (ex is HttpException)
{
    var httpException = (HttpException)ex;

    if (httpException.GetHttpCode() == (int)HttpStatusCode.NotFound)
        return; // Do nothing 404    
}

Answer 3

I know that this sounds very easy, or very simple, or you may search for the error code, but this is what I do - simple check if the error contains the message of dose not exist:

lastErrorWrapper.ToString().Contains("does not exist.")