“没有为一个或多个必需参数提供值” VB.Net GridView 更新

Question

我有一个Access DB 并通过VB.NET 连接到它。

首先，我在GridView 中显示一个表记录，用户可以对其进行更新。用户更新后，他会按Button 以从GridView 中获取更新的数据并更新Access 数据库。

但在执行此操作时，我收到错误 No value given for one or more required parameters. 我在这里缺少什么？

代码：

 Dim sConnectionString As String _
       = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\DB.accdb;Persist Security Info=False;"

Dim myConnection As OleDbConnection
Dim myAdapter As OleDbDataAdapter
Dim myTable As DataTable

Private Sub form1_Shown(sender As Object, e As EventArgs) Handles MyBase.Shown
        myConnection = New OleDbConnection(sConnectionString)
        Dim myCommand As New OleDbCommand("SELECT ID,Test FROM T1", myConnection)
        myConnection.Open()
        myAdapter = New OleDbDataAdapter(myCommand)
        myTable = New DataTable()
        myAdapter.Fill(myTable)
        setDataGridDataSource(myTable)
        setLabelTxt("Row Count: " + myTable.Rows.Count.ToString(), RowCount)
        DataGridView1.AllowUserToAddRows = True
        DataGridView1.AllowUserToDeleteRows = True
        DataGridView1.EditMode = DataGridViewEditMode.EditOnEnter
        myConnection.Close()
    End Sub

Private Sub button1_Click(sender As Object, e As EventArgs) Handles button1.Click
    Me.Validate()
    Dim command As OleDbCommand = New OleDbCommand("UPDATE T1 SET ID = ? , Test = ? WHERE ID = ?;", myConnection)
    myAdapter.UpdateCommand = command
    myAdapter.Update(myTable)
    myTable.AcceptChanges()
End Sub

Answer 1

带有文本“UPDATE T1 SET ID = ? , Test = ? WHERE ID = ?;”的 sql 命令需要 3 个参数，但您没有在代码中的任何位置设置它们。 See this example 并将参数分配给您的命令，如下所示：

cmd.Parameters.AddWithValue("ID", txtID.Text);
cmd.Parameters.AddWithValue("Test", txtTest.Text);
... and so on

Answer 2

代码应该编辑成这样：

Private Sub button1_Click(sender As Object, e As EventArgs) Handles button1.Click
        Me.Validate()
        Dim cmdBuilder As OleDbCommandBuilder = New OleDbCommandBuilder(myAdapter)
        Dim changes As DataTable = myTable.GetChanges
        If changes IsNot Nothing Then
            myAdapter.Update(myTable)
        End If
        myTable.AcceptChanges()
End Sub