datagridview access row when added without the need to loop through rows

Samir Ibrahim 1 Reputation point
2021-01-19T08:45:57.767+00:00

I have a datagridview to represent journal voucher debit/credit binded to bindingsource

when I code Me.dgv_jv.DataSource = bs_jv the dgv is populated with data

while the dgv is populated, I want to check a table field "DBCR" if equal CR then I want to add 8 spaces to ACC_NAME (I know how to do that)

I tried the code below, but it seems it execute this sub 4 times although I have 2 row 

    Private Sub dgv_jv_RowsAdded(sender As Object, e As DataGridViewRowsAddedEventArgs) Handles dgv_jv.RowsAdded            
            MsgBox("e.RowIndex = " + e.RowIndex.ToString + vbCrLf + "dgv_jv.RowCount = " + dgv_jv.RowCount.ToString)                                        
    End Sub

I can create a variable to make this sub executed once, or i can loop through rows and do my changes

is there a datagridview event that will catch rows insert only once?

VB
VB
An object-oriented programming language developed by Microsoft that is implemented on the .NET Framework. Previously known as Visual Basic .NET.
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  1. Viorel 112.7K Reputation points
    2021-01-19T10:00:35.403+00:00

    If you want to add the spaces for formatting purposes, I think that you can consider the CellFormatting event. See how ShortFormDateFormat was used to display a custom value: https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.datagridview.cellformatting.

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  2. Karen Payne MVP 35,196 Reputation points
    2021-01-19T13:08:25.04+00:00

    Hello,

    One way to achieve this is to setup the DataGridView with a DataSource using a BindingList and BindingSource and subscribe to DataSourceChanged event of the BindingSource.

    Full source

    https://github.com/karenpayneoregon/visual-basic-getting-started/tree/master/BindingList_ListChanged_1

    In the example below the following class represents the container for displaying, adding, editing and deleting in the DataGridView. Note INotifyPropertyChanged provides the ability for the DataGridView to be notified of changes and reflect this visually. The code in Person class may seem like a lot but it's worth the effort.

    58135-11111111111.png

    Container 

    Imports System.ComponentModel  
Imports System.Runtime.CompilerServices  
  
Public Class Person  
    Implements INotifyPropertyChanged  
  
    Private _firstName As String  
    Private _lastName As String  
    Private _personId As Integer  
  
    Public Property PersonId() As Integer  
        Get  
            Return _personId  
        End Get  
        Set  
            _personId = Value  
            OnPropertyChanged()  
        End Set  
    End Property  
  
    Public Property FirstName() As String  
        Get  
            Return _firstName  
        End Get  
        Set  
            _firstName = Value  
            OnPropertyChanged()  
        End Set  
    End Property  
  
    Public Property LastName() As String  
        Get  
            Return _lastName  
        End Get  
        Set  
            _lastName = Value  
            OnPropertyChanged()  
        End Set  
    End Property  
    Public Event PropertyChanged As PropertyChangedEventHandler _  
        Implements INotifyPropertyChanged.PropertyChanged  
  
    Protected Overridable Sub OnPropertyChanged(  
        <CallerMemberName> Optional memberName As String = Nothing)  
  
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(memberName))  
  
    End Sub  
  
    Public Overrides Function ToString() As String  
        Return $"{PersonId} {FirstName} {LastName}"  
    End Function  
End Class

    Load

    Here I use mocked data 

    Public Class DataOperations  
  
    Public Shared Function LoadPeople() As List(Of Person)  
        Return New List(Of Person) From {  
            New Person() With {.PersonId = 1, .FirstName = "Karen", .LastName = "Payne"},  
            New Person() With {.PersonId = 2, .FirstName = "Bill", .LastName = "Miller"},  
            New Person() With {.PersonId = 3, .FirstName = "Anne", .LastName = "Adams"}}  
    End Function  
End Class

    Form code

    Here DataSourceChanged is fired when personBindList = New BindingList(Of Person)(peopleList) is called. I check for FirstName equal to Karen and change it. 

    Imports System.ComponentModel  
  
Public Class Form1  
    Private personBindList As New BindingList(Of Person)  
    WithEvents personBindingSource As New BindingSource  
  
    Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown  
        PeopleDataGridView.AutoGenerateColumns = False  
  
        Dim peopleList = DataOperations.LoadPeople()  
  
        personBindList = New BindingList(Of Person)(peopleList)  
  
        personBindingSource.DataSource = personBindList  
        PeopleDataGridView.DataSource = personBindingSource  
  
    End Sub  
  
    Private Sub personBindingSource_DataSourceChanged(sender As Object, e As EventArgs) _  
        Handles personBindingSource.DataSourceChanged  
  
        For index As Integer = 0 To personBindList.Count - 1  
            If personBindList(index).FirstName = "Karen" Then  
                personBindList(index).FirstName = "Karen 1"  
            End If  
        Next  
  
    End Sub  
End Class

    In closing

    If you are using a DataTable as the DataSource for the BindingSource the above will still work without the Person class as DataSourceChanged event will still be triggered.

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