如何在 vb.net 中自动完成 TextBox 后调用 Keydown TextBox [已关闭]

问：

如何在 vb.net 中自动完成 TextBox 后调用 Keydown TextBox。

从“自动完成”文本框中进行选择后，我按以确保代码产品是否在数据库中，但是在我从“自动完成文本框”中选择适当的代码后，问题就出现了，然后按Enter键，然后出现所有消息框。我的代码有问题吗？

谢谢

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
 Using conn = New OleDbConnection(connectionString)
            conn.Open()
            resultList = conn.Query(Of Items)("SELECT * FROM Items").ToList()
            TextBox1.AutoCompleteMode = AutoCompleteMode.Suggest
            TextBox1.AutoCompleteSource = AutoCompleteSource.CustomSource
            TextBox1.AutoCompleteCustomSource.AddRange(resultList.Select(Function(n) n.CODEPRODUCT).ToArray())
  conn.Close()
        End Using
    End Sub
Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown   
    Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown
        If e.KeyCode = Keys.Enter Then
            Using conn = New OleDbConnection(connectionString)
                conn.Open()
                resultList = conn.Query(Of Items)("SELECT CODEPRODUCT FROM Items WHERE '" + TextBox1.Text + "'").ToList()
                conn.Close()
                MsgBox("Not Found product code...")
                Return
            End Using
        End If
    End Sub