sql - Visual Basic 2010 で SQL を使用して Access データベースにアイテムを追加する

Question

少し助けが必要です。

現在、このコードを使用して、Visual Basic 2010 の Access データベースにアイテムを追加しています。

Imports System
Imports System.Data
Imports System.Collections
Imports System.Windows.Forms
Imports System.Resources
Imports System.Data.OleDb
Public Class Form2
Dim myConnection = New System.Data.OleDb.OleDbConnection()
Dim SqlCommand As OleDb.OleDbCommand = New OleDb.OleDbCommand
Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    'connects to the database when the form loads
    myConnection = New System.Data.OleDb.OleDbConnection()
    myConnection.ConnectionString = "Provider =Microsoft.ACE.OLEDB.12.0; Data Source =project.accdb; Persist Security Info =False;"
    Try
        myConnection.Open()

    Catch ex As Exception
        MsgBox("Error Please Go Back And Try Again")
        Console.WriteLine(ex.Message)

    End Try
    'adds items to the dropdown menu

    Dim result As OleDb.OleDbDataReader
    Dim sqlText As String
    Dim add1 As Integer = 0

    If myConnection.State <> ConnectionState.Open Then
        MsgBox("Connection is not open")
        Exit Sub
    End If

    sqlText = "select * from groups"
    SqlCommand = New OleDbCommand(sqlText, myConnection)
    result = SqlCommand.ExecuteReader()

    Do While result.Read()
        ComboBox1.Items.Insert(add1, result.GetValue(0))
        add1 = add1 + 1
    Loop

    result = Nothing
    SqlCommand = Nothing
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    'Insert button
    Dim item As String = ""
    Dim price As String = ""
    Dim group As String = ""
    Dim dateandtime As Double
    Dim dateandtime2 As String = ""
    Dim sqlInsert As String = ""
    Dim result As Integer = -1
    Dim SqlCommand As OleDb.OleDbCommand = New OleDb.OleDbCommand

    If TextBox1.Text = "" Or TextBox2.Text = "" Then
        MsgBox("Item and Price Required!")
        Exit Sub
    End If

    item = TextBox1.Text
    price = TextBox2.Text.Trim
    group = ComboBox1.Text.Trim
    dateandtime = DateTimePicker1.Value.ToOADate()
    dateandtime2 = dateandtime.ToString
    sqlInsert = "INSERT INTO purchases (item, price, groupName, datetime) VALUES ('" + item + "', '" + price + "', '" + group + "', '" + dateandtime2 + "')"

    Try

        SqlCommand.Connection = myConnection
        SqlCommand.CommandText = sqlInsert
        result = SqlCommand.ExecuteNonQuery()

        If result = 0 Then
            MsgBox("No records inserted!")
        Else
            MsgBox(CStr(result) & " record inserted!")
        End If

        TextBox1.Clear()
        TextBox2.Clear()
        ComboBox1.Text = ""

    Catch ex As Exception
        MsgBox(ex.ToString)

    End Try

    result = -1
    SqlCommand = Nothing
End Sub

しかし、何かを追加しようとするたびに、この例外が発生します 。