将记录保存到MS Access数据库时出错

Question

我在VB中的代码中遇到了几个错误，我无法弄清楚如何解决它。

第一个错误在以下部分中说 value cannot be null parameter name: data table

da.Fill(dt, "ORDER")
    Con.Close()

第二次错误在此部分中：

 dsNewRow = ds.Tables(0).NewRow()

以下是整个代码：

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    dbProvider = "Provider=Microsoft.ACE.OLEDB.12.0;"
    dbSource = "Data Source=C:\Users\pao\Desktop\Projecto1.accdb"
    Con.ConnectionString = dbProvider & dbSource
    Con.Open()
    sql = "SELECT *FROM ORDER"
    da = New OleDb.OleDbDataAdapter(sql, Con)
    da.Fill(dt, "ORDER")
    Con.Close()
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    If name_.TextLength > 0 And address_.TextLength > 0 And key.TextLength > 0 Then
        Dim pizzaArr() = pizza.ToArray()
        Dim spagArr() = spaghetti.ToArray()
        Dim grindersArr() = grinders.ToArray()
        Dim dsNewRow As  DataRow
        For Each element As String In grindersArr
            MsgBox(element)
        Next

        dsNewRow = ds.Tables(0).NewRow()
        dsNewRow.Item(0) = key.Text
        dsNewRow.Item(1) = name_.Text
        dsNewRow.Item(2) = address_.Text
        ds.Tables("ORDER").Rows.Add(dsNewRow)
        da.Update(ds, "ORDER")
        MsgBox("ORDER ADDED", MsgBoxStyle.Information, "record")
        maxrows = ds.Tables("ORDER").Rows.Count
        ''
    Else
        MsgBox("COMPLETE THE FORM!", MsgBoxStyle.Exclamation, "INCOMPLETE!")
        Exit Sub
    End If

    '' Dim cb As New OleDb.OleDbCommandBuilder(da)
    '' Dim dsNewRow As DataRow

    ''    dsNewRow = ds.Tables("form").NewRow()
    ''  dsNewRow.Item(0) = key.Text
    ''   dsNewRow.Item(1) = name_.Text
    ''   dsNewRow.Item(2) = address_.Text

    ''   ds.Tables("form").Rows.Add(dsNewRow)

    MsgBox("RECORD ADDED", MsgBoxStyle.Information, "record")
    MaxRows = ds.Tables("form").Rows.Count 

End Sub