javascript - 如何使一个选择选项更改另一个选择中的选项

Question

我有两个下拉菜单。 SelCurrentManuf 和 selCurrentModel。我希望 selCurrentModel 中的选项根据 selCurrentManuf 中选择的选项进行更改。我该怎么做？

<asp:DropDownList runat="server" ID="selCurrentManuf"></asp:DropDownList>
<asp:DropDownList runat="server" ID="selCurrentModel"></asp:DropDownList>

这就是我目前填充 selCurrentModel 的方式

Public Sub PopulateCurrentModel()
        Dim mySelectQuery As String = "SELECT * FROM Model where ManufID = "+ selCurrentManuf.Text+";"
        Dim myConnection As New MySqlConnection(Session("localConn"))
        Dim myCommand As New MySqlCommand(mySelectQuery, myConnection)

        myConnection.Open()
        Dim myReader As MySqlDataReader
        myReader = myCommand.ExecuteReader()

        While myReader.Read
            Dim newListItem As New ListItem
            newListItem.Value = myReader.GetString("Modelid")
            newListItem.Text = myReader.GetString("desc")
            selCurrentModel.Items.Add(newListItem)
        End While

        myReader.Close()
        myConnection.Close()
    End Sub

但它只填充第一个选定的manuf，并且之后不会改变

Private Sub selCurrentManuf_SelectedIndexChanged(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles selCurrentManuf.SelectedIndexChanged

       PopulateCurrentModel()
End Sub

Answer 1

将selCurrentManuf.Text更改为selCurrentManuf.SelectedItem.Value

请注意:您存在 SQL 注入(inject)安全漏洞。请搜索 SQL 注入(inject)并修复。