ms-appdata 的脚本通知

Question

我想通过 html 文件中的按钮通知我的 web 视图并触发 javascript：

function notify(str) {
    window.external.notify(str);
}

使用wv_ScriptNotify(..., ...)捕获的事件：

void wv_ScriptNotify(object sender, NotifyEventArgs e)
{
    Color c=Colors.Red;
    if (e.CallingUri.Scheme =="ms-appx-web" || e.CallingUri.Scheme == "ms-appdata")
    {
        if (e.Value.ToLower() == "blue") c = Colors.Blue;
        else if (e.Value.ToLower() == "green") c = Colors.Green;
    }
    appendLog(string.Format("Response from script at '{0}': '{1}'", e.CallingUri, e.Value), c);
}

我在ms-appx-web上设置了html文件，它运行良好，我意识到html文件必须存储到本地文件夹中。所以我把ms-appx-web:///.../index.html改成ms-appdata:///local/.../index.html。

已经在微软论坛搜索并获取this。在那个线程上有一个使用解析器的解决方案，但我仍然感到困惑，它如何像使用 window.external.notify 一样从 javascript 通知？除了“ScriptNotify”之外，C# 端的哪种事件会从 javascript 中捕获“通知”？

---

更新

here 有一个解决方案，例如使用解析器，它说使用ms-local-stream:// 而不是使用ms-appdata://local，所以我仍然可以使用ScriptNotify 事件。但不幸的是，使用ms-appx 的示例意味着使用InstalledLocation 而不是LocalFolder。

尝试在msdn 站点中搜索和搜索ms-local-stream 的文档，但唯一的文档只是ms-local-stream 的格式，没有像ms-local-stream://appname_KEY/folder/file 这样的示例。

根据该文档，我制作了一些示例进行尝试：

public sealed class StreamUriWinRTResolver : IUriToStreamResolver
{
    /// <summary>
    /// The entry point for resolving a Uri to a stream.
    /// </summary>
    /// <param name="uri"></param>
    /// <returns></returns>
    public IAsyncOperation<IInputStream> UriToStreamAsync(Uri uri)
    {
        if (uri == null)
        {
            throw new Exception();
        }
        string path = uri.AbsolutePath;
        // Because of the signature of this method, it can't use await, so we 
        // call into a separate helper method that can use the C# await pattern.
        return getContent(path).AsAsyncOperation();
    }
    /// <summary>
    /// Helper that maps the path to package content and resolves the Uri
    /// Uses the C# await pattern to coordinate async operations
    /// </summary>
    private async Task<IInputStream> getContent(string path)
    {
        // We use a package folder as the source, but the same principle should apply
        // when supplying content from other locations
        try
        {
            // My package name is "WebViewResolver"
            // The KEY is "MyTag"
            string scheme = "ms-local-stream:///WebViewResolver_MyTag/local/MyFolderOnLocal" + path; // Invalid path
            // string scheme = "ms-local-stream:///WebViewResolver_MyTag/MyFolderOnLocal" + path; // Invalid path

            Uri localUri = new Uri(scheme);
            StorageFile f = await StorageFile.GetFileFromApplicationUriAsync(localUri);
            IRandomAccessStream stream = await f.OpenAsync(FileAccessMode.Read);
            return stream.GetInputStreamAt(0);
        }
        catch (Exception) { throw new Exception("Invalid path"); }
    }
}

在我的 MainPage.xaml.cs 中：

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    // The 'Host' part of the URI for the ms-local-stream protocol needs to be a combination of the package name
    // and an application-defined key, which identifies the specific resolver, in this case 'MyTag'.

    Uri url = wv.BuildLocalStreamUri("MyTag", "index.html");
    StreamUriWinRTResolver myResolver = new StreamUriWinRTResolver();

    // Pass the resolver object to the navigate call.
    wv.NavigateToLocalStreamUri(url, myResolver);
}

当它到达StorageFile f = await StorageFile.GetFileFromApplicationUriAsync(localUri); 行时总是得到异常。

如果有人遇到过这个问题并且已经解决了，请指教。

Answer 1

调试后发现了一个有意思的地方，BuildLocalStreamUri 部分已经自动生成了ms-local-stream。

我对@9​​87654324@类中的getContent方法做了一些改动：

public sealed class StreamUriWinRTResolver : IUriToStreamResolver
{
    /// <summary>
    /// The entry point for resolving a Uri to a stream.
    /// </summary>
    /// <param name="uri"></param>
    /// <returns></returns>
    public IAsyncOperation<IInputStream> UriToStreamAsync(Uri uri)
    {
        if (uri == null)
        {
            throw new Exception();
        }
        string path = uri.AbsolutePath;
        // Because of the signature of this method, it can't use await, so we 
        // call into a separate helper method that can use the C# await pattern.
        return getContent(path).AsAsyncOperation();
    }
    /// <summary>
    /// Helper that maps the path to package content and resolves the Uri
    /// Uses the C# await pattern to coordinate async operations
    /// </summary>
    private async Task<IInputStream> getContent(string path)
    {
        // We use a package folder as the source, but the same principle should apply
        // when supplying content from other locations
        try
        {
            // Don't use "ms-appdata:///" on the scheme string, because inside the path
            // will contain "/local/MyFolderOnLocal/index.html"
            string scheme = "ms-appdata://" + path;

            Uri localUri = new Uri(scheme);
            StorageFile f = await StorageFile.GetFileFromApplicationUriAsync(localUri);
            IRandomAccessStream stream = await f.OpenAsync(FileAccessMode.Read);
            return stream.GetInputStreamAt(0);
        }
        catch (Exception) { throw new Exception("Invalid path"); }
    }
}

更改 MainPage.xaml.cs 上的文件路径：

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    // The 'Host' part of the URI for the ms-local-stream protocol needs to be a combination of the package name
    // and an application-defined key, which identifies the specific resolver, in this case 'MyTag'.

    Uri url = wv.BuildLocalStreamUri("MyTag", "/local/MyFolderOnLocal/index.html");
    StreamUriWinRTResolver myResolver = new StreamUriWinRTResolver();

    // Pass the resolver object to the navigate call.
    wv.NavigateToLocalStreamUri(url, myResolver);
    wv.ScriptNotify += wv_ScriptNotify;
}

protected override void wv_ScriptNotify(object sender, NavigationEventArgs e)
{
    if (e.CallingUri.Scheme == "ms-local-stream")
    {
        // Do your work here...
    }
}