如何从本地 HTML 文件运行 C# 代码？

Question

I am currently re-coding my Epic-Games-Launcher-Like project in wpf (because it looked like trash in WinForm), but for making The old version i hard-coded all game pages. I wanted to go around this by using a webBrowser which downloads a string (which is the html-code) and loads it, but now i have the problem that i dont know how to run C# Code from a HTML file. I would be happy about any kind of help.

EDIT: I could also think about loading a xaml file.

Answer 1

If you are actually displaying the html page in a webBrowser and the user interacts with it (as a GUI - kindda) You can build the html-page in a way that when a user clicks anything that should call external C# code - it will actually just change the url such as:

https://{your_url_here}/page.html#open_gta

or

https://{your_url_here}/page.html?open_app=gta&somemore=agrs

And write some code that will handle and detect url change, when the url is changing fetch it and check if it has a "special" url that will need an action. (you could switch case any option that can happen, such as open game, buy things etc..)

(and direct answer - I don't think you can directly execute c# code from plain html)

Answer 2

The current control used to display web content in a desktop application is WebView2 . The older WebBrowser control uses Internet Explorer, which means it's incompatible with modern HTML and simply shouldn't be used.

If the question is How do I talk to the host from the web page the WebView2 control's Communication between host and web content shows how to send messages from the web page to the application and vice versa.

Sending messages to the form

The web page can use the window.chrome.webview.postMessage method to send a message to the desktop application (host). That message a can be anything that can be serialized to Json.

The WebView2 control will raise the WebMessageReceived event when a message is posted. The event argument contains the original message as JSON but can also return it as a simple string through the TryGetWebMessageAsString

Copying from the doc examples, the following code listens to the WebMessageReceived and receives a string message from the HTML page:

async void InitializeAsync()
{
    await webView.EnsureCoreWebView2Async(null);
    webView.CoreWebView2.WebMessageReceived += UpdateAddressBar;
}

void UpdateAddressBar(object sender, CoreWebView2WebMessageReceivedEventArgs args)
{
    String uri = args.TryGetWebMessageAsString();
    addressBar.Text = uri;
}

The web page sends this message to its host with:

window.chrome.webview.postMessage(window.document.URL);

Sending messages to the page

The host can send messages to the page using the CoreWebView2.PostWebMessageAsString or CoreWebView2.PostWebMessageAsJSON methods. The web page can listen for them using window.chrome.webview.addEventListener .

Copying from the docs, the web page can listen for messages by creating an event listener when it loads, eg:

window.chrome.webview.addEventListener('message', event => alert(event.data));

The form sends back the message it received to the web page with:

void UpdateAddressBar(object sender, CoreWebView2WebMessageReceivedEventArgs args)
{
    String uri = args.TryGetWebMessageAsString();
    addressBar.Text = uri;
    webView.CoreWebView2.PostWebMessageAsString("Hello " + uri);
}

Answer 3

I made a Minecraft Launcher for Hack CLients some time ago and it had to be a C# Application, but because I wanted it to look nice and WinForm Controls are very limited, I designed a Web Application.

For the WinForm I used the Nuget Package "Cefsharp Browser", in which I was able to load my HTML/PHP File.

You can then create simple JavaScript Functions like the following:

    function launchClient(client) {
        mcl_desktop.test(client);
    }

    function BuyInfoMessage(){
        mcl_desktop.test("Die Kauffunktion wurde noch nicht implementiert");
    }

In C#, in Form1() you can put this Code as example

            String callbackObj = "mcl_desktop";

            CefSettings settings = new CefSettings();
            Cef.Initialize(settings);
            Cef.EnableHighDPISupport();

            settings.CefCommandLineArgs.Add("disable-gpu", "1");
            settings.RemoteDebuggingPort = 8088;

            InitializeComponent();
            chromiumWebBrowser1.LoadingStateChanged += loaded;
            chromiumWebBrowser1.Load("http://localhost/mcl/");


            chromiumWebBrowser1.JavascriptObjectRepository.Settings.LegacyBindingEnabled = true;
            chromiumWebBrowser1.JavascriptObjectRepository.Register(callbackObj, new Interface(), isAsync: true);

Important is the string callbackObj and the last line saying new Interface() (= new class called Interface.cs).

And in this class are all defined Methods/Functions like in the Javascript part. This would be my Interface.cs

        public void BuyInfoMessage(string text, string title = "MCL")
        {
            MessageBox.Show(text, title);
        }

        public void downloadClient(string url, string filename)
        {
            using (var client = new WebClient())
            {
                client.DownloadFile(url,  filename);
            }

            if(File.Exists(localClients + "\\" + filename))
            {

            }
        }

        public void launchClient(string path)
        {
            // code to launch client
        }

It is actually pretty simple if you take some time to think about it and it is really cool