DeviceSpecific 類別

提供建構，用以在 <DeviceSpecific> 項目的多個內容替代選擇中指定一個選項。

命名空間： System.Web.UI.MobileControls
組件： System.Web.Mobile (在 system.web.mobile.dll 中)

語法

'宣告
Public Class DeviceSpecific
    Inherits Control
'用途
Dim instance As DeviceSpecific

public class DeviceSpecific : Control

public ref class DeviceSpecific : public Control

public class DeviceSpecific extends Control

public class DeviceSpecific extends Control

備註

在 <DeviceSpecific> 項目中，您通常會指定一或多個 <Choice> 項目，每個項目都包含屬性 (Attribute)，其針對目標裝置功能指定評估選項的方式。在執行階段，會依序評估每個選項，並且使用第一個通過評估的選項。DeviceSpecific/Choice 建構會用來指定樣板集和覆寫屬性；例如，此建構可用於指定 Image 控制項的裝置專屬影像。

注意事項
即使 DeviceSpecific 類別 (Class) 繼承自 Web Form System.Web.UI.Control 命名空間，它也只是實作 (Implementation) 詳細資料。<Choice> 項目的行為不同於控制項。

範例

在下列程式碼中，示範了如何使用 DeviceSpecific 和 DeviceSpecificChoice 物件在行動表單中建立各種裝置特定的介面。

注意事項
以下程式碼範例使用單一檔案程式碼模型，如果直接複製到程式碼後置 (Code-Behind) 檔案即可能無法作用。這個程式碼範例必須複製到副檔名為 .aspx 的空白文字檔。如需詳細資訊，請參閱 ASP.NET Web 網頁程式碼模型。

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

<script runat="server">
    Private Sub Form_Init(ByVal sender As Object, ByVal e As EventArgs)
        ' Create a DeviceSpecific group for Choice elements
        Dim devSpecific As New DeviceSpecific()
        Dim ipa As IParserAccessor

        ' Create two Choice objects, one with a filter
        For i As Integer = 0 To 1
            Dim devChoice As DeviceSpecificChoice
            Dim custTemplate As ITemplate

            ' Create a Choice object 
            devChoice = New DeviceSpecificChoice()
            ' Only the first Choice has a filter (must be in Web.config)
            If i = 0 Then
                devChoice.Filter = "isHTML32"

                ' Create the header template.
                custTemplate = New CustomTemplate("HeaderTemplate")
                ' Put header template in a new container
                custTemplate.InstantiateIn(New TemplateContainer())
                ' Add the header template to the Choice
                devChoice.Templates.Add("HeaderTemplate", custTemplate)

                ' Create the footer template
                custTemplate = New CustomTemplate("FooterTemplate")
                ' Put footer template in a new container
                custTemplate.InstantiateIn(New TemplateContainer())
                ' Add the footer template to the Choice
                devChoice.Templates.Add("FooterTemplate", custTemplate)
            End If
            
            ' Add the Choice to the DeviceSpecific
            ipa = CType(devSpecific, IParserAccessor)
            ipa.AddParsedSubObject(devChoice)
        Next

        ' Add the DeviceSpecific object to the form
        ipa = CType(Form1, IParserAccessor)
        ipa.AddParsedSubObject(devSpecific)
    End Sub

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

        Dim lab As System.Web.UI.MobileControls.Label
        lab = CType(Form1.Header.FindControl("Label1"), _
            System.Web.UI.MobileControls.Label)
        If IsNothing(lab) Then Return

        ' Get the selected choice's filter name
        Dim filterName As String = _
        Form1.DeviceSpecific.SelectedChoice.Filter
        If filterName = "isHTML32" Then
            lab.Text += " - HTML32"
        Else
            lab.Text += " - Default"
        End If
    End Sub

    Public Class CustomTemplate
        Implements ITemplate
        Dim templName As String

        ' Constructor
        Public Sub New(ByVal TemplateName As String)
            templName = TemplateName
        End Sub

        Public Sub InstantiateIn(ByVal container As Control) _
            Implements ITemplate.InstantiateIn
            
            If templName = "HeaderTemplate" Then
                ' Create a label
                Dim lab As New System.Web.UI.MobileControls.Label
                lab.Text = "Header Template"
                lab.ID = "Label1"

                ' Create a command
                Dim cmd As New Command()
                cmd.Text = "Submit"

                ' Add controls to the container
                container.Controls.Add(lab)
                container.Controls.Add(cmd)
            
            ElseIf templName = "FooterTemplate" Then
                ' Create a label
                Dim lab As System.Web.UI.MobileControls.Label
                lab = New System.Web.UI.MobileControls.Label()
                lab.ID = "Label2"
                lab.Text = "Footer Template"

                ' Add label to the container
                container.Controls.Add(lab)
            End If
        End Sub
    End Class

</script>

<html xmlns="http:'www.w3.org/1999/xhtml" >
<body>
    <mobile:form id="Form1" runat="server" 
        OnInit="Form_Init">
    </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 runat="server">
    private void Form_Init(object sender, System.EventArgs e)
    {
        // Create a DeviceSpecific group for Choice elements
        DeviceSpecific devSpecific = new DeviceSpecific();

        // Create two Choice objects, one with a filter
        for (int i = 0; i < 2; i++)
        {
            DeviceSpecificChoice devChoice;
            ITemplate custTemplate;

            // Create a Choice object 
            devChoice = new DeviceSpecificChoice();
            // Only the first Choice has a filter (must be in Web.config)
            if (i == 0)
                devChoice.Filter = "isHTML32";

            // Create the header template.
            custTemplate = new CustomTemplate("HeaderTemplate");
            // Put header template in a new container
            custTemplate.InstantiateIn(new TemplateContainer());
            // Add the header template to the Choice
            devChoice.Templates.Add("HeaderTemplate", custTemplate);

            // Create the footer template
            custTemplate = new CustomTemplate("FooterTemplate");
            // Put footer template in a new container
            custTemplate.InstantiateIn(new TemplateContainer());
            // Add the footer template to the Choice
            devChoice.Templates.Add("FooterTemplate", custTemplate);

            // Add the Choice to the DeviceSpecific
            ((IParserAccessor)devSpecific).AddParsedSubObject(devChoice);
        }

        // Add the DeviceSpecific object to the form
        ((IParserAccessor)Form1).AddParsedSubObject(devSpecific);
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        System.Web.UI.MobileControls.Label lab;
        lab = (System.Web.UI.MobileControls.Label)Form1.Header.FindControl("Label1");
        if (lab == null)
            return;

        // Get the selected choice's filter name
        string filterName = 
            Form1.DeviceSpecific.SelectedChoice.Filter;
        if (filterName == "isHTML32")
            lab.Text += " - HTML32";
        else
            lab.Text += " - Default";
    }

    public class CustomTemplate : ITemplate
    {
        String templateName;

        // Constructor
        public CustomTemplate(string TemplateName)
        {
            templateName = TemplateName;
        }

        public void InstantiateIn(Control container)
        {
            if (templateName == "HeaderTemplate")
            {
                // Create a label
                System.Web.UI.MobileControls.Label lab;
                lab = new System.Web.UI.MobileControls.Label();
                lab.Text = "Header Template";
                lab.ID = "Label1";

                // Create a command
                Command cmd = new Command();
                cmd.Text = "Submit";

                // Add controls to the container
                container.Controls.Add(lab);
                container.Controls.Add(cmd);
            }
            else if (templateName == "FooterTemplate")
            {
                // Create a label
                System.Web.UI.MobileControls.Label lab;
                lab = new System.Web.UI.MobileControls.Label();
                lab.ID = "Label2";
                lab.Text = "Footer Template";

                // Add label to the container
                container.Controls.Add(lab);
            }
        }
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<body>
    <mobile:form id="Form1" runat="server" OnInit="Form_Init">
    </mobile:form>
</body>
</html>

所有上述程式碼都可以使用下列標記以宣告方式取代：

<html xmlns="http://www.w3.org/1999/xhtml" >
<body>
    <mobile:Form id="Form1" runat="server">
        <mobile:DeviceSpecific Runat="server">
            <Choice Filter="isHTML32">
                <HeaderTemplate>
                    <mobile:Label ID="Label1" Runat="server">
                        Header Template - HTML32</mobile:Label>
                    <mobile:Command Runat="server">
                        Submit</mobile:Command>
                </HeaderTemplate>
                <FooterTemplate>
                    <mobile:Label ID="Label2" Runat="server">
                        Footer Template</mobile:Label>
                </FooterTemplate>
            </Choice>
            <Choice>
                <HeaderTemplate>
                    <mobile:Label ID="Label1" Runat="server">
                        Header Template - Default</mobile:Label>
                    <mobile:Command ID="Command1" Runat="server">
                        Submit</mobile:Command>
                </HeaderTemplate>
                <FooterTemplate>
                    <mobile:Label ID="Label2" Runat="server">
                        Footer Template</mobile:Label>
                </FooterTemplate>
            </Choice>
        </mobile:DeviceSpecific>
    </mobile:Form>
</body>
</html>

在這些範例中，Web.config 檔必須含有下列項目：

<!-- In Web.config file -->
<deviceFilters>
  <filter name="isHTML32" compare="PreferredRenderingType" argument="html32" />
</deviceFilters>

.NET Framework 安全性

• AspNetHostingPermission  用於裝載環境中的作業。要求值：LinkDemand，權限值：Minimal。
• AspNetHostingPermission  用於裝載環境中的作業。要求值：InheritanceDemand，權限值：Minimal。

繼承階層架構

System.Object
   System.Web.UI.Control
    System.Web.UI.MobileControls.DeviceSpecific

執行緒安全

這個型別的所有公用靜態成員 (即 Visual Basic 中的 Shared 成員) 都是安全執行緒。並非所有的執行個體成員均為安全執行緒。

平台

Windows 98、 Windows 2000 SP4、 Windows Millennium Edition、 Windows Server 2003、 Windows XP Media Center Edition、 Windows XP Professional x64 Edition、 Windows XP SP2、 Windows XP Starter Edition

.NET Framework 並不支援各種平台的所有版本。如需支援平台版本的相關資訊，請參閱系統需求一節的內容。

版本資訊

.NET Framework

支援版本：2.0、1.1

請參閱

參考

DeviceSpecific 成員
System.Web.UI.MobileControls 命名空間
Choices

其他資源

<DeviceSpecific> 項目
<Choice> 項目 (.NET Framework 開發人員手冊)
DeviceSpecific 控制項簡介