System.NullReferenceException: Object reference not set to an instance of an object
Si riferisce a questa riga:
dcat.SelectedIndex = dcat.Items.IndexOf(dcat.Items.FindByText(lcat.Text ))



Private Sub DataGrid1_EditCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs ) Handles DataGrid1.EditCommand

Dim dcat As DropDownList
Dim lcat As Label
With dcat
lcat = DataGrid1.Items(e.Item.ItemIndex).Cells(0).FindCon trol("lcat")

DataGrid1.EditItemIndex = e.Item.ItemIndex
DataGrid1.DataBind()

dcat = DataGrid1.Items(e.Item.ItemIndex).Cells(0).FindCon trol("dcat")

dcat.DataSource = DataSet21
dcat.DataTextField = "CATEGORIA"
dcat.DataValueField = "CATEGORIA"
dcat.DataBind()
dcat.SelectedIndex = dcat.Items.IndexOf(dcat.Items.FindByText(lcat.Text ))
End With

End Sub