Render Exceptions in an Entity Framework application

Did you know that exceptions thrown by Entity Framework contain useful information? They are buried in some properties of an inner exception. Here's the code that makes them visible:

public static class Extensions
{
    /// <summary>
    /// Renders an exception with messages and stack traces
    /// </summary>
    /// <param name="ex">The exception to render</param>    
    /// <param name="noTrace">Whether trace information should be omitted</param>
    /// <returns>A string containing messages and stack traces</returns>
    public static string Render(this Exception ex, bool noTrace = false)
    {
        var s = new StringBuilder("\n");
        int i = 0;
        do
        {
            s.AppendFormat("{0:#\\. inner E;;E}xception ({1}):\n   {2}\n", 
                i++, 
                ex.GetType().Name, 
                ex.Message.Replace("\n", "\n   "));
            if (ex is UpdateException)
            {
                foreach (var stateEntry in ((UpdateException)ex).StateEntries)
                {
                    var entity = stateEntry.Entity ?? new object();
                    s.AppendFormat("     {0} {1}: {2}\n", stateEntry.State, entity.GetType().Name, entity);
                    var values =
                        stateEntry.State == EntityState.Deleted
                            ? stateEntry.OriginalValues
                            : stateEntry.CurrentValues;
                    for (int j = 0; j < values.FieldCount; j++)
                    {
                        var currentValue = values[j];
                        var originalValue =
                            stateEntry.State == EntityState.Added
                                ? currentValue
                                : stateEntry.OriginalValues[j];
                        s.AppendFormat(originalValue.Equals(currentValue) ? "      {0}: <{1}>\n" : "      {0}: <{1}>→<{2}\n",
                                       values.GetName(j), originalValue, currentValue);
                    }
                }
            }
            s.AppendFormat(noTrace ? "\n" : "Trace:\n{0}\n", ex.StackTrace);
            ex = ex.InnerException;
        }
        while (ex != null);
        return s.ToString();
    }
}