How to determine if a string value is in XML format?

Question

I am connecting with an API, or service as you wish, which returns an xml when it finds data in the database, but unfortunately it returns a string if nothing is found or an error occurs. In my application I am using the following code to connect to this API and recover the data:

 WebRequest request = WebRequest.Create(_fileUrl);

 HttpWebResponse response = (HttpWebResponse) request.GetResponse();

 Stream dataStream = response.GetResponseStream();

 var reader = new StreamReader(dataStream);

 string responseFromServer = reader.ReadToEnd();

 xmlDoc.LoadXml(responseFromServer);

As expected when there is no data in the database an error occurs when loading xmlDoc because the responseFromServer variable is not XML but a string.

The question is: How do I identify whether my string returned an xml or not? I don’t want to ""try" to load and if it doesn’t work out that what came was a string. I may be masking other errors while doing so.

Answer 1

You can check whether response.ContentType corresponds to application/xml or text/xml and use this information to make the decision. If the service is well configured, it should send this header (and send text/plain to the error message).