Exception when adding a new row from the RowLeave event-CodePudding

I have an unbound datagridview, set the option to allow user to add row to True, and all I want is that once I "complete" a row, the datagridview automatically should create a new empty row, so I set the method

DataGridView1.Rows.Add()

in the DataGridView1_Leave event, but once the row is finished and exception comes out: An unhandled exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll - Unable to complete this operation in this event handler What does it mean? It should be plain simple code, but I don't know how to solve

Here is the situation: That's the recipient DataGridView. When I'm on the first blank row (which is created by the AllowUserToAddRow = true) and I press F3 a modal form is opened with another DataGridView containing products to select

and here's the code for the KeyDown event in the recipient DataGridView

Private Sub DataGridView1_KeyDown(sender As Object, e As KeyEventArgs) Handles DataGridView1.KeyDown
    If e.KeyCode = Keys.F3 Then
        If frmZoomArticoli.ShowDialog = Windows.Forms.DialogResult.OK Then
                            Dim codart As String = frmZoomArticoli.DataGridView1.CurrentCell.Value.ToString()
            RicercaxCodiceArticolo(codart)
        End If
    End If
End Sub

Here the sub RicercaxCodiceArticolo(codart) which fills the recipient DataGridView with the selected product:

Private Sub RicercaxCodiceArticolo(ByVal codiceart As String)

    Dim strsql As String
    Dim cmd As SqlCommand
    Dim source As New BindingSource

    'Dichiariamo le variabili che ospitano i dati di riga
    Dim codice As String
    Dim descrizione As String
    Dim unitamisura As String
    Dim quantita As Double = 1.0
    Dim codiceiva As Double
    Dim costobase As Double
    Dim prezzobase As Double
    Dim costoultimo As Double
    Dim giacenza As Double
    Dim sconto1 As Double
    Dim sconto2 As Double

    connection.Open()
    strsql = "SELECT CODICEARTICOLO AS 'Codice', DESCRIZIONEARTICOLO AS 'Descrizione', UNITAMISURA AS 'Um', CODICEIVA AS 'Iva' " _
            & ", COSTOBASE AS 'Costo', PREZZOBASE AS 'Prezzo', SCONTO1 As 'Sc1', SCONTO2 As 'Sc2', COSTOULTIMO AS 'CostoUlt' " _
            & ", BARCODE AS 'Barcode', NOTEARTICOLO AS 'Note' ,CATEGORIAARTICOLO AS 'Categ.Art.', GIACENZA AS 'Giacenza' " _
            & ", FORNITOREPREF AS 'Fornit. Pref.' FROM Articoli " _
            & " WHERE CODICEARTICOLO = '" & codiceart & "'"

    cmd = New SqlCommand()
    cmd.CommandText = strsql
    cmd.CommandType = CommandType.Text
    cmd.Connection = connection
    source.DataSource = cmd.ExecuteReader()

    'Assegniamo i dati letti nel bindingsource alle variabili
    codice = source.Current!Codice
    descrizione = source.Current!Descrizione
    unitamisura = source.Current!Um
    codiceiva = Convert.ToDouble(source.Current!Iva)
    costobase = Convert.ToDouble(source.Current!Costo)
    prezzobase = Convert.ToDouble(source.Current!Prezzo)
    costoultimo = Convert.ToDouble(source.Current!Costoult)
    giacenza = Convert.ToDouble(source.Current!Giacenza)
    sconto1 = Convert.ToDouble(source.Current!Sc1)
    sconto2 = Convert.ToDouble(source.Current!Sc2)

    'Riempiamo le celle con i dati estratti dal BindingSource
    With DataGridView1.CurrentRow
        .Cells("grdCodice").Value = codice
        .Cells("grdDescrizione").Value = descrizione
        .Cells("grdUM").Value = source.Current!Um
        .Cells("grdQuantita").Value = quantita
        If TipoMovimento = "Carico" Then
            .Cells("grdPrezzoUnitario").Value = source.Current!CostoUlt
        Else
            .Cells("grdPrezzoUnitario").Value = source.Current!Prezzo
        End If
        .Cells("grdSconto1").Value = sconto1
        .Cells("grdSconto2").Value = sconto2
        .Cells("grdSconto3").Value = 0.0
        .Cells("grdSconto4").Value = 0.0
        'Per calcolare il prezzo totale di riga dobbiamo tenere presente le
        'informazioni che abbiamo gia' in anagrafica, ovvero il costo/prezzo
        'e gli sconti

        'Blocco di controllo sul tipo movimento
        If TipoMovimento = "Carico" Then
            If sconto1 > 0 Then
                .Cells("grdPrezzoTotale").Value = quantita * (costoultimo * (costoultimo * sconto1 / 100))
            Else
                .Cells("grdPrezzoTotale").Value = quantita * costoultimo
            End If
        ElseIf TipoMovimento = "Scarico" Then
            If sconto1 > 0 Then
                .Cells("grdPrezzoTotale").Value = quantita * (prezzobase * (prezzobase * sconto1 / 100))
            Else
                .Cells("grdPrezzoTotale").Value = quantita * prezzobase
            End If
        End If

        .Cells("grdAliquotaIva").Value = codiceiva
    End With

    connection.Close()

End Sub

and that's the result in the recipient DataGridView:

now, suppose that I don't want to edit the selected row because I don't need to edit quantity, or price, or whatever, but I just want to insert a new row to keep inserting other products. When I tab until the end of the row I want to create a new row, and that's why I wrote the DataGridView1.Rows.Add() in the RowLeave event of the DataGridView, but that's where the exception occurs: I'm sorry for all the descriptions are in italian, but if you need any other details feel free to ask. If there's nothing I can do all that remains is to add a button outside the DataGridView which adds a new row from there. Any other solution is welcomed.

CodePudding user response：

Is there some reason you do not use a DataSource for the grid? Then you could simply add the row to the DataSource.

If you insist on manually adding the rows, then the problem you currently have is that the code is never “adding” a new row to the grid. The code simply uses the grids CurrentRow to set the values. This may work but the grids “new” row will not get created.

It is questionable to use the grids CurrentRow in this manner... So instead of using the grids CurrentRow for this, I suggest you “add” a new row in the RicercaxCodiceArticolo method. Something like below should add the new row and the “new-new” empty row should be at the bottom…

Dim newRowIndex As Int32
newRowIndex = DataGridView1.Rows.Add()
With DataGridView1.Rows(newRowIndex)
    .Cells("grdCodice").Value = codice
    .Cells("grdDescrizione").Value = descrizione
    '.....
End With