用Javascript為DropDownList控件下拉式選擇添加一個Item至定義索引位置。 準備數據，創建一個對象，將是存儲DropDownList控件每個Item數據。 代碼如下: Imports Microsoft.VisualBasic Namespace Insus.NET Public Class Catalog Private _ID As Integer Private _Name As String Public Property ID As Integer Get Return _ID End Get Set(value As Integer) _ID = value End Set End Property Public Property Name As String Get Return _Name End Get Set(value As String) _Name = value End Set End Property End Class End Namespace
在.aspx.vb綁定數據： 代碼如下: Imports Insus.NET Partial Class _Default Inherits System.Web.UI.Page Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load If Not IsPostBack Then Data_Binding() End If End Sub Private Sub Data_Binding() Me.DropDownListCatalog.DataSource = GetData() Me.DropDownListCatalog.DataValueField = "ID" Me.DropDownListCatalog.DataTextField = "Name" Me.DropDownListCatalog.DataBind() End Sub Private Function GetData() As List(Of Catalog) Dim cls As New List(Of Catalog) Dim cl As Catalog = New Catalog() cl.ID = 1 cl.Name = "新聞頻道" cls.Add(cl) cl = New Catalog() cl.ID = 2 cl.Name = "體育頻道" cls.Add(cl) cl = New Catalog() cl.ID = 3 cl.Name = "軍事頻道" cls.Add(cl) cl = New Catalog() cl.ID = 4 cl.Name = "教育頻道" cls.Add(cl) Return cls End Function End Class
準備數據與環境后，寫Javascript: 代碼如下: window.onload = function () { var catalog = document.getElementById("<%=DropDownListCatalog.ClientID%>"); var obj = document.createElement("option") obj.text = "請選擇..." obj.value = 0 catalog.options.insertBefore(obj, catalog.options[0]); }
