How to check for valid xml in string input before calling .LoadXml()

Chris_Ballance_1551 0
Viewed 97756

I would much prefer to do this without catching an exception in LoadXml() and using this results as part of my logic. Any ideas for a solution that doesn't involve manually parsing the xml myself? I think VB has a return value of false for this function instead of throwing an XmlException. Xml input is provided from the user. Thanks much!

if (!loaded)
{
     this.m_xTableStructure = new XmlDocument();
     try
     {
          this.m_xTableStructure.LoadXml(input);
          loaded = true;
     }
     catch
     {
          loaded = false;
     }
}
exception-handling xml .net c#
5 Answers

Just catch the exception. The small overhead from catching an exception drowns compared to parsing the XML.

If you want the function (for stylistic reasons, not for performance), implement it yourself:

public class MyXmlDocument: XmlDocument
{
  bool TryParseXml(string xml){
    try{
      ParseXml(xml);
      return true;
    }catch(XmlException e){
      return false;
    }
 }
Rasmus_Faber_55420

Using a XmlValidatingReader will prevent the exceptions, if you provide your own ValidationEventHandler.

user_82200

If catching is too much for you, then you might want to validate the XML beforehand, using an XML Schema, to make sure that the XML is ok, But that will probably be worse than catching.

Mart237n_Marconcini_26840

AS already been said, I'd rather catch the exception, but using XmlParserContext, you could try to parse "manually" and intercept any anomaly; however, unless you're parsing 100 xml fragments per second, why not catching the exception?

Mart237n_Marconcini_26840
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