ติด .ExecuteNonQuery() ExecuteNonQuery: Connection property has not been initialized.

Imports System.Data.SqlClient
Imports System.Data.OleDb
Public Class info_com

    Private Property OleDbConnection As OleDbConnection

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

    End Sub

    Private Sub Linkpage1ToolStripButton_Click(sender As Object, e As EventArgs)
        Try
            Me.Info_comTableAdapter.linkpage1(Me.ฐานข้อมูลงานซ่อมDataSet.info_com)
        Catch ex As System.Exception
            System.Windows.Forms.MessageBox.Show(ex.Message)
        End Try

    End Sub

    Private Sub ToolStripButton1_Click(sender As Object, e As EventArgs) Handles ToolStripButton1.Click
        Dim incom As New info_com
        incom.Show()
        incom.Hide()
    End Sub

    Private Sub ToolStripButton2_Click(sender As Object, e As EventArgs) Handles ToolStripButton2.Click
        Dim sale As New Sale
        sale.Show()

    End Sub

    Private Sub ToolStripButton3_Click(sender As Object, e As EventArgs) Handles ToolStripButton3.Click
        Dim sm As New SaveModify
        sm.Show()

    End Sub
   
    
    Private Sub save_Click(sender As Object, e As EventArgs) Handles save.Click
        
        Dim sqlADD As String = ""
        Dim cm As New OleDbCommand
        sqlADD = "INSERT INTO info_com(รหัสเครื่อง,IP_Address,Computer_Name,User_Login,Location)"
        sqlADD &= "VALUES ('" & tb1.Text & "','" & tb2.Text & "','" & tb3.Text & "','" & tb4.Text & "','" & tb5.Text & "')"

        If MessageBox.Show("คุณต้องการเพิ่มรายชื่อใหม่ใช่หรือไม่?", "ยืนยัน", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = Windows.Forms.DialogResult.Yes Then
            With cm

                .CommandType = CommandType.Text
                .CommandText = sqlADD
                .Connection = Conn()
                'cm.ExecuteNonQuery()

            End With
            MessageBox.Show("เพิ่มรายชื่อพนักงานแล้ว", "ผลการทำงาน", MessageBoxButtons.OK, MessageBoxIcon.Information)
            tb1.Clear()
            tb2.Clear()
            tb3.Clear()
            tb4.Clear()
            tb5.Clear()
            DataGridView1.Refresh()
        End If
    End Sub

    Private Function Conn() As OleDbConnection
        Conn = New OleDbConnection(" Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\parn\Documents\Visual Studio 2012\Projects\โปรแกรมงานซ่อม\โปรแกรมงานซ่อม.mdb;Persist Security Info=False;")
        Conn.Open()
    End Function


End Class