If you’re querying SharePoint content using a CAML query from code it’s a good habit to always populate the SPQuery instance’s ViewFields property. Otherwise the returned SPListItem instances might not contain any data for certain fields and throw an exception when you try to access those fields.

Specifying ViewFields involves creating a string of CAML FieldRef elements. For instance if we want our query to return items that contain data for the Title, Created and ID field we use this:

   1: <FieldRef Name='Title'/><FieldRef Name='Created'/><FieldRef Name='ID'/>

As you can see there’s some overhead of boilerplate markup involved. I’ve written a small piece of code that I always use to make my life a little easier. Today I happened to post this code in a reply I wrote on the MSDN forums and also decided to submit it as Community Content to the official SPQuery docs on MSDN. Then I thought I might as well share it with you here. So here it is:

   1: public static string BuildViewFieldsXml(params string[] fieldNames)

   2: {

   3:     const string TEMPLATE = @"<FieldRef Name='{0:S}'/>";

   4:     StringBuilder sb = new StringBuilder();

   5:     foreach (string fieldName in fieldNames)

   6:     {

   7:         sb.AppendFormat(TEMPLATE, fieldName);

   8:     }

   9:     return sb.ToString();

  10: }

  11:  

  12: // Use it like this:

  13: SPQuery query = new SPQuery();

  14: query.ViewFields = BuildViewFieldsXml("Title", "Created", "ID");

  15:  

  16: // Note that you can specify a variable amount of string parameters, i.e.

  17: query.ViewFields = BuildViewFieldsXml("Title", "Created", "ID", "Author", "Gender");

Yeah, you’re right. This piece of code isn’t exactly rocket science. But you might appreciate it anyway 🙂