How Do I Return Blank Value From Datagridview To Datetimepicker When Cell Is Clicked Vb 10

'for clear the date value 
Sub clear()
        dtpDOJ.Text = " "
End sub

'for return value to datetime picker when datagridview is clicked
 Private Sub dgvdatakaryawan_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles dgvdatakaryawan.CellContentClick
 Dim i As Integer
        Dim n As Integer = dgvdatakaryawan.Rows.Count
        If n = 0 Then
            Call clear()
        Else
            Try
                i = dgvdatakaryawan.CurrentRow.Index
                dtpDOJ.Text = dgvdatakaryawan.Item(1, i).Value
            Catch ex As Exception

            End Try
        End If
   End Sub

'this is property of datetimepicker
Private Sub dtpDOJ_ValueChanged_1(ByVal sender As System.Object, ByVal e As      System.EventArgs) Handles dtpDOJ.ValueChanged
        Me.dtpDOJ.Format = Windows.Forms.DateTimePickerFormat.Custom
        Me.dtpDOJ.CustomFormat = "dd MMMM yyyy"
    End Sub