在 C# 中无法使用 CefSharp 的网站上的回调

Question

Im trying to get a callback using cefsharp on a website i dont own.

On the launching of my application i bind the tag "cb"

chromeBrowser.JavascriptObjectRepository.Register("cb", new BoundObject(), true);

public class BoundObject
{
     public void dosomthing()
     {
          MessageBox.Show("It worked!");
     }
}

Using the following javascript script i add an object to the website:

function insertBefore(el, referenceNode) {
    referenceNode.parentNode.insertBefore(el, referenceNode);
}

var newEl = document.createElement('div');
newEl.className = 'exampleclass';
newEl.innerHTML = '<a onclick="cb.dosomthing();">Do somthing</a>';

var ref = document.getElementById('example-tab');

insertBefore(newEl, ref);

I perform this using:

ExecuteScriptAsyncWhenPageLoaded

Then when i click the added in element with the text "Do somthing", nothing happens.

What am i doing wrong?

Answer 1

JavaScript binding requires that you call CefSharp.BindObjectAsync in javascript before you can access the object. I also recommend wrapping your code in an anon closure when it's more than a single line.

An example would look something like

(async function()
{
    await CefSharp.BindObjectAsync("cb");

    //Object with name cb will have been bound, you can now access

    function insertBefore(el, referenceNode) {
        referenceNode.parentNode.insertBefore(el, referenceNode);
    }

    var newEl = document.createElement('div');
    newEl.className = 'exampleclass';
    newEl.innerHTML = '<a onclick="cb.dosomthing();">Do somthing</a>';

    var ref = document.getElementById('example-tab');

    insertBefore(newEl, ref);
})();

Also MessageBox.Show should be called on the UI thread, the BoundObject.dosomething method will be called on a background thread. A simple solution is to pass a reference to your Form/Window/Control (not sure if you are using WinForms or WPF , so I cannot say exactly) then Invoke the call back onto your UI thread. For testing purposes what you have should be ok, if you want to do anything more serious then you should change your code.