vb.net 索引所选单元格的行

Question

i showing my table in a data grid then i want to update this table from the grid itself i am using this code but this error keeps showing The class 'System.Windows.Forms.DataGridViewRow' cannot be indexed because it has no default property.

Private Sub edit()
    Dim cnx As New MySqlConnection("datasource=localhost;database=bdgeststock;username=root;password=")
    Dim cmd As MySqlCommand = cnx.CreateCommand
    Dim resultat As Integer
    Dim req As String = "UPDATE utilisateur  SET @col = @val where idu=@id"
    If grid.CurrentCell.ColumnIndex = 1 Then
        MessageBox.Show("error u cant edit ids")
    Else
        If ConnectionState.Open Then
            cnx.Close()
        End If
        cnx.Open()
        cmd.Parameters.AddWithValue("@col", grid.CurrentCell.ColumnIndex)
        cmd.Parameters.AddWithValue("@val", grid.CurrentCell.Value)
        cmd.Parameters.AddWithValue("@id", grid.CurrentRow(0))
        cmd.CommandText = req
        resultat = cmd.ExecuteNonQuery
        If (resultat = 0) Then
            MessageBox.Show("error")
        Else
            MessageBox.Show("success")
        End If
        grid.EndEdit()
        grid.RefreshEdit()
        grid.ReadOnly = True
        cnx.Close()
        cmd.Dispose()
    End If

End Sub

Answer 1

Calling grid.CurrentRow(0) won't work. grid.CurrentRow returns a datagridviewrow, but as the errror message says, this cannot be indexed (means "cannot have a number in brackets put after it") because it has no default property (means the property that is returned when the developer uses just the name). Some things do have default properties; for example a DataRow (of a datatable) has a .Items property representing the values of the columns. .Items is a default property meaning that myDatarow.Items(7) and myDataRow(7) do exactly the same thing. DataGridViewRow doesn't have any of its properties marked as a default one, so you have to specify one of its properties

Perhaps you meant

grid.CurrentRow.Cells(0).Value

Now might be a good time to mention that this is isn't the way MS intended a datagridview be used. It would be better to bind your grid to a datatable, and then pull the data items you want out of the datatable.

You might also, if your grid is bound to a datatable:

DirectCast(grid.CurrentRow.DataBoundItem, DataRowView)(0)

I would recommend ensuring that you don't allow the user to change the order of columns in the DGV. If you do, then consider one of:

grid.CurrentRow.Cells("id").Value

DirectCast(grid.CurrentRow.DataBoundItem, DataRowView)("id")