Fix the issue with GetDataItemsByIds method in EditableItemSelectionAttribute.

The issue is when Parameter.In is being called, since the second parameter is "param object[] anyOf" it takes the integer array as the first item in the object[] instead of converting it to an array of objects that causes runtime error.

More information about param object[] in the following page, http://msdn.microsoft.com/en-us/library/w5zay9db.aspx