Question

I am using StringBuilder AppendLine to insert some lines to be shown in a javascript alert box. The alert box is not firing and wehn I see the view source I get the following:

alert("Void SendMail(Int32): 
Line number: 0 
Object reference not set to an instance of an object.
");

StringBuilder code:

sb.AppendLine(string.Format("{0}: ", frame.GetMethod()));
sb.AppendLine(string.Format("Line number: {0} ", frame.GetFileLineNumber()));
sb.AppendLine(ex.Message);

Please tell me how to fix this ?

Answer 1

Instead of StringBuilder.ToString() you should probably use StringBuilder.ToString().Replace(Environment.NewLine, "\\n"). This should escape the newlines in the javascript, so the result is:

alert("Void SendMail(Int32):\nLine number: 0 \nObject reference not set to an instance of an object.\n");

I genuinely hope you’re logging the exception somewhere serverside too.