To hide a particular column in XAML you would use something like the following.

<igDP:XamDataGrid x:Name="myGrid" >

   <igDP:XamDataGrid.FieldLayouts>

      <igDP:FieldLayout>

         <igDP:FieldLayout.Fields>

            <igDP:Field Name="myColumn" Visibility="Collapsed"  />

         </igDP:FieldLayout.Fields>

      </igDP:FieldLayout>

   </igDP:XamDataGrid.FieldLayouts>

</igDP:XamDataGrid>

Hope this helps.