In order to fill-in a WinGrid I do the following

source = (UltraDataSource) myGrid.DataSource
myObjCollection = GetMyObjCollection()
Dim row(source.Band.Columns.Count - 1) As Object

Foreach myObj in myObjCollection
    i = 0
    row(i++) = myObj.myProperty1
    row(i++) = myObj.myProperty2
    ...
    Dim uRow = source.Rows.Add(False, row, False)
    uRow.Tag = myObj
Next myObj

Now we have a lot of rows in the grid filled with data of myObjCollection.

So, once some of my rows are selected by user, I want to recuperate the BO from the rows tags,

I use:

Foreach row in myGrid.Selected.Rows
    row.Tag = Nothing ' WHY? How to recuperate the DataSource Row Tag value?

PS. Actually I do it like this:

      For Each row In grdResult.Selected.Rows
        Dim mySourceRow = TryCast(row.ListObject, UltraDataRow)
        If mySourceRow IsNot Nothing Then
          Dim myObj = TryCast(mySourceRow.Tag, MyObjClass)
          If myObj IsNot Nothing Then
            myObj.Selected = True
          End If
        End If
      Next row

But perhaps there is a more elegant way to do it...