Question

I have the following xml

<Objects>
    <Object>
        <ViewAngle>90</ViewAngle>
        <ViewMode>ThirdPerson</ViewMode>
        <Top>50</Top>
        <Left>100</Left>
    </Object>
</Objects>

I have the following code to read this xml

           XmlDataDocument doc = new XmlDataDocument();
           doc.Load(xmlPath);
           XmlElement root = doc.DocumentElement;
           XmlNodeList nodes = root.SelectNodes("/Objects/Object");
           foreach (XmlNode node in nodes)
           {
                if (node.InnerXml.Contains("View"))
                {
                  string viewType=node["View"].InnerText;
                  //..... other stuffs
                }
                if (node.InnerXml.Contains("ViewAngle"))
                {
                  string viewAngle=node["ViewAngle"].InnerText;
                  //..... other stuffs
                }
                if (node.InnerXml.Contains("ViewMode"))
                {
                  string viewMode=node["ViewMode"].InnerText;
                  //..... other stuffs
                }
           }

Above code is working fine if my xml contains one more tag i.e. <View>3dView</View>. But if it does not contains the View tag, then it produces error.

The InnerXml.Contains() is a simple string method that checks for the sub-string is present in the string or not.

In my case the Contains("View") returns true as View is present in ViewAngle and in ViewMode that is why it is going inside the if block of View but when it tries to read the node["View"], it produces error as View node is not exists in the xml.

How to resolve this error?

Answer 1

You are missing the fact that XML is structured data, not string. This is completely the wrong approach:

if (node.InnerXml.Contains("View")) {
  // ...
}

You want this:

XmlNode child = node.SelectSingleNode("./View");
if (child != null) {
  // now do something with 'child' ...
}