從集合元素建立清單物件

發行項
08/21/2008

更新：2007 年 11 月

下列步驟描述行動 List 控制項如何從集合中的項目建構 MobileListItem 執行個體 (Instance)：

控制項會檢查是否已定義 DataTextField 或 DataValueField 屬性。如果已定義這些屬性，則控制項會使用這些欄位名稱來探索項目的屬性，並設定 MobileListItem 執行個體的 Text 和 Value 屬性。
如果 DataTextField 或 DataValueField 屬性都沒有定義，控制項便會將 MobileListItem 執行個體的 Text 和 Value 屬性設定為該項目的字串表示 (使用 ToString 方法)。
如果有定義 ItemDataBind 事件處理常式，便會呼叫該處理常式。您可以使用此處理常式設定 MobileListItem 執行個體的屬性。

當提供預設呈現時，清單控制項便會以其 Text 屬性來表示 MobileListItem 執行個體。在樣板化呈現中，樣板可呈現 MobileListItem執行個體或是相關聯資料繫結物件所需要的屬性。

如果已設定 ItemsAsLinks 屬性，List 控制項便會將項目呈現為超連結 (Hyperlink)。Text 屬性的值會成為連結文字，而且 Value 屬性的值會成為目標 URL。

處理選取項目

如果您的清單太複雜，如物件陣列，則無法透過選取項目直接存取選取項目的成員。然而，如果您適當設計應用程式，則可存取關聯的物件。如果您正在建立要填入 (Populate) 清單的物件群組，即可讓群組成為全域陣列，然後將傳回的值當做陣列的索引處理，如下列程式碼範例所示。

<%@ Page Language="VB" 
    Inherits="System.Web.UI.MobileControls.MobilePage" %>
<%@ Register TagPrefix="mobile" 
    Namespace="System.Web.UI.MobileControls" 
    Assembly="System.Web.Mobile" %>

<script >
    Private customers(3) As Person

    Private Class Person
        Private _Name, _Nickname, _Initials As String

        Public Sub New(ByVal name As String, _
            ByVal nickname As String, ByVal initials As String)
            Me._Name = name
            Me._Nickname = nickname
            Me._Initials = initials
        End Sub

        Public ReadOnly Property Name() As String
            Get
                Return _Name
            End Get
        End Property
        Public ReadOnly Property Nickname() As String
            Get
                Return _Nickname
            End Get
        End Property
        Public ReadOnly Property Initials() As String
            Get
                Return _Initials
            End Get
        End Property
    End Class

    Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
        ReDim customers(2)
        customers(0) = New Person("George Washington", "George", "GW")
        customers(1) = New Person("Abraham Lincoln", "Abe", "AL")
        customers(2) = New Person("Theodore Roosevelt", "Teddy", "TR")

        If (Not IsPostBack) Then
            ' Bind the array to the list.
            List1.DataSource = customers
            List1.DataTextField = "Name"
            List1.DataBind()
        End If
    End Sub

    Protected Sub List1_ItemCommand(ByVal sender As Object, _
        ByVal e As ListCommandEventArgs)

        Dim selectedPerson As Person = customers(e.ListItem.Index)
        Label1.Text = String.Format("{0} (AKA {1}), initials {2}", _
            selectedPerson.Name, selectedPerson.Nickname, _
            selectedPerson.Initials)

        ActiveForm = Form2
    End Sub

    Protected Sub Command1_Click(ByVal sender As Object, _
        ByVal e As EventArgs)

        Me.ActiveForm = Me.Form1
    End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<body>
    <mobile:form id="Form1" >
        <mobile:List ID="List1" Runat="server" OnItemCommand="List1_ItemCommand">
        </mobile:List>
    </mobile:form>
    <mobile:Form ID="Form2" Runat="server">
        <mobile:Label ID="Label1" >Label</mobile:Label>
        <mobile:Command ID="Command1" Runat="server" OnClick="Command1_Click">Return to Form1</mobile:Command>
    </mobile:Form>
</body>
</html>

<%@ Page Language="C#" 
    Inherits="System.Web.UI.MobileControls.MobilePage" %>
<%@ Register TagPrefix="mobile" 
    Namespace="System.Web.UI.MobileControls" 
    Assembly="System.Web.Mobile" %>

<script >
    private Person[] customers = new Person[3];

    private class Person
    {
        private String _Name, _Nickname, _Initials;

        public Person(String name, String nickname, String initials)
        {
            this._Name     = name;
            this._Nickname = nickname;
            this._Initials = initials;
        }

        public String Name     { get { return _Name;     } }
        public String Nickname { get { return _Nickname; } }
        public String Initials { get { return _Initials; } }
    }

    private void Page_Load(object sender, System.EventArgs e)
    {
        customers[0] = new Person("George Washington", "George", "GW");
        customers[1] = new Person("Abraham Lincoln", "Abe", "AL");
        customers[2] = new Person("Theodore Roosevelt", "Teddy", "TR");

        if(!IsPostBack)
        {
            // Bind the array to the list.
            List1.DataSource    = customers;
            List1.DataTextField = "Name";
            List1.DataBind();
        }
    }

    private void List1_ItemCommand(object sender, 
        ListCommandEventArgs e)
    {
        Person selectedPerson = customers[e.ListItem.Index];
        Label1.Text = String.Format("{0} (AKA {1}), initials {2}", 
            selectedPerson.Name, selectedPerson.Nickname,
            selectedPerson.Initials);

        ActiveForm = Form2;
    }

    protected void Command1_Click(object sender, EventArgs e)
    {
        this.ActiveForm = this.Form1;
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<body>
    <mobile:form id="Form1" >
        <mobile:List ID="List1" Runat="server" OnItemCommand="List1_ItemCommand">
        </mobile:List>
    </mobile:form>
    <mobile:Form ID="Form2" Runat="server">
        <mobile:Label ID="Label1" >Label</mobile:Label>
        <mobile:Command ID="Command1" Runat="server" OnClick="Command1_Click">Return to Form1</mobile:Command>
    </mobile:Form>
</body>
</html>

請參閱

概念

使用列出的控制項存取資料

共用方式為

從集合元素建立清單物件

處理選取項目

請參閱

概念

其他資源