parsing this XML in C# for a SharePoint Field

Question

I have the below field xml which I get after calling a web service. I am getting the error

Name cannot begin with the '=' character, hexadecimal value 0x3D. Line 1, position 2325.

<Field DisplayName='Maximum_x0020_characters_x0020_a' FillInChoice='TRUE' Format ='RadioButtons' Type ='Choice' StaticName ='Maximum_x0020_characters_x0020_a' Required='TRUE' Name='Maximum_x0020_characters_x0020_a'><Default></Default><CHOICES><CHOICE>True</CHOICE><CHOICE>False</CHOICE><CHOICE>True</CHOICE><CHOICE>False</CHOICE><CHOICE>>=255</CHOICE><CHOICE><=255</CHOICE><CHOICE>>=510</CHOICE><CHOICE><= 510</CHOICE></CHOICES></Field>

Can anyone please suggest the correct way of replacing the special character. I tried replacing &lt and &gt for > and < but then I get another error.

Answer 1

I added the special character part in CDATA tag and it worked. For Example I was having the XML of the choice field where choices were coming with special characters which was causing the issue. To overcome it, I added the choice tag of XML in the *** part and it worked.

CDATA takes the value as simple text.

str.Append("<CHOICE><![CDATA[" + choices[k] + "]]></CHOICE>");

Choices[k] are my choice value which I am fetching from code.

Answer 2

If you create a choice column using the browser and enter >=250 <=510 etc as choices, and then look at the SchemaXml property of the column (for example using a tool like SharePoint Manager), you can see how they are encoded internally by SharePoint, and help troubleshooting. In this case:

<CHOICE>&gt;=255</CHOICE>
<CHOICE>&lt;=255</CHOICE>
<CHOICE>&gt;=510</CHOICE>

Perhaps you were missing the semicolon (;) from lt; and gt;.

CDATA is also a valid option, but for simple cases like these when only a character needs to be encoded, encoding them individually makes the code cleaner.