Private Function GetDataSetFromTable() As DataSet
    Dim table As DataTable

    ' Check to see if the DataGrid's DataSource property
    ' is a DataTable.
    If TypeOf dataGrid1.DataSource Is DataTable Then
        table = CType(DataGrid1.DataSource, DataTable)
        GetDataSetFromTable = table.DataSet
    Else
        return Nothing
    End If
End Function

private DataSet GetDataSetFromTable()
{
    DataTable table;

    // Check to see if the DataGrid's DataSource
    // is a DataTable.
    if( dataGrid1.DataSource is DataTable)
    {
        table = (DataTable) dataGrid1.DataSource;
        // Return the DataTable's DataSet
        return table.DataSet;
    }
    else
    {
        return null;
    }
}