Silverlight Interop 8 - 傳遞Dictionary<string, string>到Javascript端

2010-06-02 03:47 PM

做實驗驗證了Silverlight傳送Dictionary<string, string>到Javascript端的行為。

依據MSDN文件的說法:

By default, properties and return values typed as IDictionary are returned by reference, using a JavaScript wrapper that is similar to a dictionary.

Javascript Dictionary Wrapper提供obj[key]、obj.key的存取方式，並可新增key/value，但不支援for (var p in obj)的Javascript Key列舉。如果想要支援Key列舉及其他功能，還是得回歸Javascript Object。

以下程式示範傳回Dictionary<string, string>及將其轉為Javascript Object的兩種做法:

public Page()

    InitializeComponent();

    if (HtmlPage.IsEnabled)

        HtmlPage.RegisterScriptableObject("JSIO", this);

[ScriptableMember]

public Dictionary<string, string> GetDictionary()

    Dictionary<string, string> dict = new Dictionary<string, string>();

    dict.Add("A", "公理號");

    dict.Add("B", "大買家");

    //會傳回被Javascript Dictionary Wrapper包裝的Managed Object到Javscript端

    return dict;

[ScriptableMember]

public ScriptObject GetJSDictionary()

    //將Dictionary<string, string>轉成標準Javascript Object

    Dictionary<string, string> dct = GetDictionary();

    ScriptObject jsDct = HtmlPage.Window.Eval("new Object()") as ScriptObject;

    foreach (string k in dct.Keys)

        jsDct.SetProperty(k, dct[k]);

    return jsDct;

前端測試時，for (var p in d1)迴圈執行次數為零，但可以使用d1.A或d1["B"]存取Dictionary內的儲存值；包裝為Javascript Object後，使用起來就如同一般物件，支援for (var p in d2)。

    function onSilverlightLoad(sender, args) {

        var slCtl = sender.getHost();

        var jsio = slCtl.Content.JSIO;

        var d1 = jsio.GetDictionary();

        for (var p in d1)

            alert("d1.Foreach: " + p);

        alert("d1.A=" + d1.A); alert("d1.B=" + d1["B"]);

        var d2 = jsio.GetJSDictionary();

        for (var p in d2)

            alert("d2.Foreach: " + p + "->" + d2[p]);

Silverlight Interop 8 - 傳遞Dictionary<string, string>到Javascript端

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