How do I resolve the error “Expression must evaluate to a node-set” when checking for the existence of a node?

Question

I\'m attempting to check for the existence of a node using the following .NET code:

xmlDocument.SelectSingleNode(
        String.Format(\"//ErrorTable/Projec         


        

Answer 1

The XPath expression contained a subtle error. It should have been:

xmlDocument.SelectSingleNode(String.Format("//ErrorTable/ProjectName[text()='{0}']", projectName));

The previous expression was evaluating to a boolean, which explains the exception error. Thanks for the help!