Windows Form BindingSource Error: object reference not set to an instance of an object

Hi kana250688,

On button Update click convert the BindingSource to SortableBindingList and check if count greater than zero then update the record.

Use the following code.

VB.Net

Imports System.Data.OleDb
Imports Dapper

Public Class Form1
    Private _criteriasBindingList As New SortableBindingList(Of Person)()
    Private bindingSource As BindingSource = Nothing
    Dim PersonService As New PersonService()

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        loaddata()
    End Sub
    Private Sub loaddata()
        _criteriasBindingList = New SortableBindingList(Of Person)(CType(PersonService.GetPERSON(), IList(Of Person)))
        bindingSource = New BindingSource With {.DataSource = _criteriasBindingList}
        DataGridView1.DataSource = bindingSource 'Set the data source.
    End Sub

    Private Sub myFilter(str1 As String, str2 As String)
        If (String.IsNullOrEmpty(str1) AndAlso String.IsNullOrEmpty(str2)) Then
            bindingSource.DataSource = _criteriasBindingList
        ElseIf (String.IsNullOrEmpty(str1)) Then
            bindingSource.DataSource = _criteriasBindingList.Where(Function(c) c.DATE.ToString("dd-MM-yyyy").Contains(str2)).ToList()
        ElseIf (String.IsNullOrEmpty(str2)) Then
            bindingSource.DataSource = _criteriasBindingList.Where(Function(c) c.NAMEPERSON.ToLower().Contains(str1)).ToList()
        Else
            bindingSource.DataSource = _criteriasBindingList.Where(Function(c) c.NAMEPERSON.ToLower().Contains(str1) AndAlso c.DATE.ToString("dd-MM-yyyy").Contains(str2)).ToList()
        End If
    End Sub
    Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TXTNAME.KeyUp
        Dim str1 = TXTNAME.Text.Trim().ToLower()
        Dim str2 = TXTDATE.Text.Trim().ToLower().Replace("/ /", "")
        myFilter(str1, str2)
    End Sub

    Private Sub TextBox2_KeyDown(sender As Object, e As KeyEventArgs) Handles TXTDATE.KeyUp
        Dim str1 = TXTNAME.Text.Trim().ToLower()
        Dim str2 = TXTDATE.Text.Trim().ToLower().Replace("/ /", "")
        myFilter(str1, str2)
    End Sub

    Private Sub BtnUpdate_Click(sender As Object, e As EventArgs) Handles BtnUpdate.Click
        Try
            _criteriasBindingList = New SortableBindingList(Of Person)(CType(bindingSource.DataSource, IList(Of Person)))
            Dim i As Integer = 0
            If _criteriasBindingList.Count > 0 Then
                For Each person As Person In _criteriasBindingList
                    Dim Update = New Person With {
                                     .TIME = TXTTIME.Text,
                                     .OTHERS1 = TXTOTHERS1.Text,
                                     .OTHERS2 = TXTOTHERS2.Text,
                                     .NAMEPERSON = person.NAMEPERSON,
                                     .DATE = person.DATE}
                    PersonService.UpdatePerson(Update)
                    _criteriasBindingList.Item(i).TIME = TXTTIME.Text
                    _criteriasBindingList.Item(i).OTHERS1 = TXTOTHERS1.Text
                    _criteriasBindingList.Item(i).OTHERS2 = TXTOTHERS2.Text
                    i = i + 1
                Next
                bindingSource = New BindingSource With {.DataSource = _criteriasBindingList}
                DataGridView1.DataSource = bindingSource
                MessageBox.Show("Person In successfully updated")
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Myapp", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        End Try
    End Sub
End Class

Public Class Person
    Public Property ID As Integer
    Public Property NAMEPERSON As String
    Public Property AGE As Integer
    Public Property [POSITION] As String
    Public Property [DATE] As DateTime
    Public Property DAYS As String
    Public Property TIME() As String
    Public Property OTHERS1 As String
    Public Property OTHERS2 As String
    Public Property OTHERS3 As String
End Class

Public Class PersonService
    Public Function GetOledbConnectionString() As String
        Return "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Person.accdb;Persist Security Info=False;"
    End Function
    Private ReadOnly _conn As OleDbConnection
    Private _connectionString As String = GetOledbConnectionString()
    Public Sub New()
        _conn = New OleDbConnection(_connectionString)
    End Sub
    Public Function GetPERSON() As IEnumerable(Of Person)
        Dim sql = "SELECT PERSON.ID AS [ID],MASTERID.NAMEPERSON AS [NAMEPERSON],PERSON.AGE AS [AGE],[PERSON.POSITION] AS [POSITION],PERSON.DATE AS [DATE],format(PERSON.DATE,'dddd') AS [DAYS],PERSON.TIME AS [TIME],PERSON.Others1 AS [OTHERS1],PERSON.Others2 AS [OTHERS2],PERSON.Others3 AS [OTHERS3] FROM PERSON INNER JOIN MASTERID ON PERSON.ID = MASTERID.ID"
        Using _conn = New OleDbConnection(GetOledbConnectionString())
            Return _conn.Query(Of Person)(sql).ToList()
        End Using
    End Function
    Public Sub UpdatePerson(ByVal Obj As Person)
        Try
            Dim sql = $"UPDATE PERSON INNER JOIN MASTERID ON (PERSON.ID = MASTERID.ID) Set PERSON.TIME = '{Obj.TIME}',PERSON.OTHERS1 = '{Obj.OTHERS1}',PERSON.OTHERS2 = '{Obj.OTHERS2}' WHERE MASTERID.NAMEPERSON = '{Obj.NAMEPERSON}' AND PERSON.DATE = #{Obj.DATE}# ;"
            Using _conn = New OleDbConnection(GetOledbConnectionString())
                _conn.Execute(sql)
            End Using
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Myapp", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        End Try
    End Sub
End Class

Screenshot