How to Log Exception in a file?

Question

I want to be able to do logging in every catch block. Something like this.

catch (Exception exception)
{
  Logger.Write(exception);
}

and then the settings in the configuration will pick up the Message and StackTrace property etc using customer listener.

I would like to use Enterprise Library Logging Application Block. I'm sure someone must have done this already.

Answer 1

Others have posted some good links on getting the Logging Application Block (LAB) working so I won't duplicate that here.

In terms of formatting your exception you have 3 choices that I can think of:

1. Use the default Exception.ToString() implementation (it's not bad)
2. Write a Custom Formatter that integrates into the LAB.
3. Write a helper function that performs the formatting and passes the string into the Write method.

If option 1 doesn't meet your needs then I would recommend going with option 3 (since option 2 is overkill).

A simple example would be something like:

    catch (Exception exception)
    {
        Logger.Write(LogHelper.CreateExceptionString(exception));
    }

    ...

    public static string CreateExceptionString(Exception e)
    {
        StringBuilder sb = new StringBuilder();
        CreateExceptionString(sb, e);

        return sb.ToString();
    }

    private static void CreateExceptionString(
        StringBuilder sb,
        Exception e,
        string indent = "")
    {
        if (indent.Length > 0)
        {
            sb.AppendFormat("{0}Inner ", indent);
        }

        sb.AppendFormat("Exception Found:\n{0}Type: {1}",
            indent, e.GetType().FullName);
        sb.AppendFormat("\n{0}Message: {1}",
            indent, e.Message);
        sb.AppendFormat("\n{0}Source: {1}",
            indent, e.Source);
        sb.AppendFormat("\n{0}Stacktrace: {1}",
            indent, e.StackTrace);

        if (e.InnerException != null)
        {
            sb.Append("\n");
            CreateExceptionString(sb, e.InnerException, indent + "  ");
        }
    }