Auto number increment

Question

Hello everyone, i have issues with auto increment in DataGridView row count. As i adding columns in table, i get numbers of rows in right order, but when i delete a row, for example number 4, my ID skip reordering and continue to add next number of the row...any suggestion?

Answer 1

Hi @DRGAGI ,
You can use the following function to set DataGridView's row numbers.

    Private Sub SetRowNumber(ByVal dgv As DataGridView)  
        For Each row As DataGridViewRow In dgv.Rows  
            row.HeaderCell.Value = (row.Index + 1).ToString()  
        Next  
    End Sub  

I make a test on my side and you can take a look.

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
        Dim dt As DataTable = New DataTable()  
        dt.Columns.Add("c1")  
        dt.Columns.Add("c2")  
        dt.Rows.Add("A", 12)  
        dt.Rows.Add("B", 21)  
        dt.Rows.Add("C", 14)  
        dt.Rows.Add("D", 18)  
        DataGridView1.DataSource = dt  
    End Sub  
  
    Private Sub DeleteRowBtn_Click(sender As Object, e As EventArgs) Handles DeleteRowBtn.Click  
        For Each item As DataGridViewRow In DataGridView1.SelectedRows  
            DataGridView1.Rows.RemoveAt(item.Index)  
        Next  
    End Sub  
  
    Private Sub DataGridView1_RowsAdded(sender As Object, e As DataGridViewRowsAddedEventArgs) Handles DataGridView1.RowsAdded  
        SetRowNumber(DataGridView1)  
    End Sub  
  
    Private Sub DataGridView1_RowsRemoved(sender As Object, e As DataGridViewRowsRemovedEventArgs) Handles DataGridView1.RowsRemoved  
        SetRowNumber(DataGridView1)  
    End Sub  
  
    Private Sub SetRowNumber(ByVal dgv As DataGridView)  
        For Each row As DataGridViewRow In dgv.Rows  
            row.HeaderCell.Value = (row.Index + 1).ToString()  
        Next  
    End Sub  

Result of my test.

Best Regards,

Xingyu Zhao
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Answer 2

Hello @DRGAGI

When working with a DataGridView the best option is to set the DataSource be it a DataTable or a List(Of T). About the only time to not use a DataSource is for viewing information/data where information/data will not be modified.

For example, using a DataTable subscribe to the RowDeleted event and in this event reorder the primary key.

Here the primary key is read-only so when reordering I set the ReadOnly property to false so the values can be set then change the ReadOnly to True again

Here I delete the row with Joe and then reorder the primary key.

Public Class Form1  
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
        Dim dt = GetData()  
  
        AddHandler dt.RowDeleted, AddressOf RowDeleted  
        DataGridView1.DataSource = dt  
  
    End Sub  

    Private Sub RowDeleted(sender As Object, e As DataRowChangeEventArgs)  
  
        Dim dt = CType(sender, DataTable)  
  
        If dt.Rows.Count > 0 Then  
  
            dt.Columns(0).ReadOnly = False  
  
            For index As Integer = 0 To dt.Rows.Count - 1  
                dt.Rows(index).SetField(Of Integer)("Id", index + 1)  
            Next  
  
            dt.Columns(0).ReadOnly = True  
  
        End If  
  
    End Sub  
End Class  
Public Module Mocked  
    Public Function GetData() As DataTable  
        Dim dt As New DataTable  
  
        dt.Columns.Add(New DataColumn() With {.ColumnName = "Id", .DataType = GetType(Integer),  
                          .AutoIncrement = True, .AutoIncrementSeed = 1})  
  
        dt.Columns.Add(New DataColumn() With {.ColumnName = "Name", .DataType = GetType(String)})  
  
        dt.Rows.Add(New Object() {Nothing, "Karen"})  
        dt.Rows.Add(New Object() {Nothing, "Jim"})  
        dt.Rows.Add(New Object() {Nothing, "Joe"})  
        dt.Rows.Add(New Object() {Nothing, "Bob"})  
        dt.Rows.Add(New Object() {Nothing, "Mary"})  
  
        Return dt  
  
    End Function  
End Module  

Answer 3

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'TODO: This line of code loads data into the 'Database13DataSet.Table1' table. You can move, or remove it, as needed.
        Me.Table1TableAdapter.Fill(Me.Database13DataSet.Table1)

    End Sub

    Private Sub Table1DataGridView_RowsAdded(sender As Object, e As DataGridViewRowsAddedEventArgs) Handles Table1DataGridView.RowsAdded

        SetRowNumber(Table1DataGridView)

    End Sub

    Private Sub SetRowNumber(table1DataGridView As DataGridView)
        For Each row As DataGridViewRow In table1DataGridView.Rows
            row.HeaderCell.Value = (row.Index + 1).ToString()
        Next

    End Sub

    Private Sub saveDatabase_Click(sender As Object, e As EventArgs) Handles saveDatabase.Click

        Me.Validate()
        Me.Table1BindingSource.EndEdit()
        Me.TableAdapterManager.UpdateAll(Me.Database13DataSet)

    End Sub

    Private Sub addNewRow_Click(sender As Object, e As EventArgs) Handles addNewRow.Click

        Table1BindingSource.AddNew()

    End Sub

    Private Sub deleteCurentRow_Click(sender As Object, e As EventArgs) Handles deleteCurentRow.Click

        For Each item As DataGridViewRow In Table1DataGridView.SelectedRows
            Table1DataGridView.Rows.RemoveAt(item.Index)
        Next

    End Sub
End Class