如何将属性添加到xml模式？

Question

I have below in memory string where I need to check the attribute "CanToggleHidden" exists or not, if not exists I need to add this attribute to the string and if "CanToggleHidden" exists I need to set the value to "TRUE". I am able to check the "CanToggleHidden" exists or not using the below code. Any help will be appreciated.

TextReader objTextReader = new StringReader(fieldSchemaXml);
XmlTextReader reader = new XmlTextReader(objTextReader);
reader.Read();
if (reader.GetAttribute("CanToggleHidden") == null)
{
}

Below is the string

    "<Field ID=\"{b77cdbcf-5dce-4937-85a7-9fc202705c91}\" Group=\"_Hidden\" SourceID=\"http://schemas.microsoft.com/sharepoint/v4\" Name=\"IconOverlay\" StaticName=\"IconOverlay\" DisplayName=\"IconOverlay\" Type=\"Text\" Required=\"FALSE\" AllowDeletion=\"TRUE\" Version=\"6\" Sealed=\"FALSE\" Hidden=\"TRUE\" CanToggleHidden=\"TRUE\" />" 

Answer 1

You can use the following, first parse the string as a proper XmlDocument. Then getting the rootnode (as the string only contains a single node, if this is not the case, you need to do a doc.GetElementById() )

[TestClass]
public class UnitTest1
{
    [TestMethod]
    public void TestMethod1()
    {
        XmlDocument doc = new XmlDocument();

        doc.LoadXml("<Field ID=\"{b77cdbcf-5dce-4937-85a7-9fc202705c91}\" Group=\"_Hidden\" SourceID=\"http://schemas.microsoft.com/sharepoint/v4\" Name=\"IconOverlay\" StaticName=\"IconOverlay\" DisplayName=\"IconOverlay\" Type=\"Text\" Required=\"FALSE\" AllowDeletion=\"TRUE\" Version=\"6\" Sealed=\"FALSE\" Hidden=\"TRUE\" CanToggleHidden=\"TRUE\" />");

        var element = doc.DocumentElement;
        if (element.Attributes["CanToggleHidden"] != null)
            element.SetAttribute("CanToggleHidden", "TRUE");

        Console.WriteLine(doc.ToString());
    }
}