Public Function IsNull ( _
    columnIndex As Integer _
) As Boolean

Dim instance As DataRow
Dim columnIndex As Integer
Dim returnValue As Boolean

returnValue = instance.IsNull(columnIndex)

public bool IsNull (
    int columnIndex
)

public:
bool IsNull (
    int columnIndex
)

public boolean IsNull (
    int columnIndex
)

public function IsNull (
    columnIndex : int
) : boolean

Private Sub IsValNull()
    ' Assuming the DataGrid is bound to a DataTable.
    Dim table As DataTable = CType(DataGrid1.DataSource, DataTable)
    Dim row As DataRow = table.Rows(datagrid1.CurrentCell.RowNumber)
    row.BeginEdit
    row(1) = System.DBNull.Value
    row.EndEdit
    row.AcceptChanges
    Console.WriteLine(row.IsNull(1))
End Sub