Adding a row to the datagrid but not the DataSet

Does anyone know how to add a row to the datagrid control.

I am binding a dataset to the datagrid and I want the user to click an "Add" button to add a new row in the grid but I do not want to add it to the dataset until the user fills out all non-null fields.

I am not able to add it to the dataset because of the schema and it does not allow nullable values in some of the fields.

The row is not added to the dataset until you update, if you have a probl;em with Null values, then craeate a data grid tablestyle and use the columnstyle function to handle null text.

an example below:
Dim tbs1 As New DataGridTableStyle()

tbs1.MappingName = "Your data set"

Dim l3 As New DataGridTextBoxColumn()
l3.MappingName = "Name"
l3.HeaderText = " Name"
l3.Width = 135
l3.NullText = ""
tbs1.GridColumnStyles.Add(l3)
DataGrid1.TableStyles.Add(tbs1)