Wpf VB.NET, datagrid how to create dynamic class

Dim x_col As New DataGridTextColumn
x_col.Header = some name
x_col.Binding = New Binding(some name)
data_grid.Columns.Add(x_col)

Dim x_row As New DataGridRow
x_row.Item = New data_grid_add_item With {.dynamic_name = value}

Public Class data_grid_add_item 
        Public Property dynamic_name As String
End Class