Question

Is this kind of grouping possible for Silverlight DataGrids?

The first three rows of the first column are combined into one block because their data are the same.

Answer 1

No, the default Silverlight datagrid control does not support this kind of grouping, however you can achive a similar result using template columns:

First you should create a Class that would contain the grouped data, something like this:

MySourceClass
{
   string GroupColumn {get;set;}
   List<object> GroupedColumn1 {get;set;}
}

Then bind your DataGrid to a collection of MySourceClass (or whatever name you call it), and create a TextColumn for Column1, and a TemplateColumn for Column2 with a ListBox or similar, and bind the source of the Listbox to the GroupedColumn property.

You might have to thinker a bit with the styles, but i’m pretty sure you can acomplish a solid look with this aproach.

EDIT:
Alternatively you could use the default DataGrid grouping, her’s a good example for it:
http://www.codeproject.com/Articles/134340/Grouping-Records-in-Silverlight-DataGrid-using-Pag