稍后偶然发现了这个2y 6m，并想将其发布给可能处于同一位置的人. 解决方案包括使用CefSharp框架和通过CefSharp执行JavaScript.

Stumbled upon this 2y 6m later and wanted to put it out to someone who might be in the same position. Solution includes usage of CefSharp framework and JavaScript execution via CefSharp.

//1. Find the Html element x and y coordinates with something like this:

var scriptTask = _browser.EvaluateScriptAsync(@"
    var play = document.getElementByClassName('image')[0]
    function findPos(obj)
    {
        var curleft = 0;
        var curtop = 0;

        if (obj.offsetParent)
        {
            do
            {
                curleft += obj.offsetLeft;
                curtop += obj.offsetTop;
            } while (obj = obj.offsetParent);

            return { X: curleft,Y: curtop};
        }
    }
    findPos(play)"
)
.ContinueWith(x =>
{
// 2. Continue with finding the coordinates and using MouseClick method 
// for pressing left mouse button down and releasing it at desired end position.
    var responseForMouseClick = x.Result;

    if (responseForMouseClick.Success && responseForMouseClick.Result != null)
    {
        var xy = responseForMouseClick.Result;
        var json = JsonConvert.SerializeObject(xy).ToString();
        var coordx = json.Substring(json.IndexOf(':') + 1, 3);
        var coordy = json.Substring(json.LastIndexOf(':') + 1, 3);

        MouseLeftDown(int.Parse(coordx) + 5, int.Parse(coordy) + 5);
        MouseLeftUp(int.Parse(coordx) + 100, int.Parse(coordy) + 100);
    }

// 3. Repeat the finding of coordinates for making focus with a click. 
// Use the HitEnter method to send the KeyEvent.
    _browser.EvaluateScriptAsync(@"
        var objForHittingEnter = document
             .getElementsByClassName('class-name-for-hitting-enter-on')[0]
                 findPos(objForHittingEnter)") // Already defined earlier
    .ContinueWith(y =>
    {
        var responseForEnter = y.Result;

        if (responseForEnter.Success && responseForEnter.Result != null)
        {
            var xy = responseForEnter.Result;
            var json = JsonConvert.SerializeObject(xy).ToString();
            var coordx = json.Substring(json.IndexOf(':') + 1, 3);
            var coordy = json.Substring(json.LastIndexOf(':') + 1, 3);

            HitEnter(int.Parse(coordx) + 2, int.Parse(coordy) + 2);
        }
    });
});


public void MouseLeftDown(int x, int y)
{
    _browser.GetBrowser().GetHost()
        .SendMouseClickEvent(x, y, MouseButtonType.Left, false, 1, CefEventFlags.None);
    Thread.Sleep(15);
}

public void MouseLeftUp(int x, int y)
{
    _browser.GetBrowser().GetHost()
        .SendMouseClickEvent(x, y, MouseButtonType.Left, true, 1, CefEventFlags.None);
    Thread.Sleep(15);
}

public void HitEnter(int x, int y)
{
    KeyEvent k = new KeyEvent
    {
        WindowsKeyCode = 0x0D, // Enter
        FocusOnEditableField = true,
        IsSystemKey = false,
        Type = KeyEventType.KeyDown
    };

    _browser.GetBrowser().GetHost().SendKeyEvent(k);

    Thread.Sleep(100);

    k = new KeyEvent
    {
        WindowsKeyCode = 0x0D, // Enter
        FocusOnEditableField = true,
        IsSystemKey = false,
        Type = KeyEventType.KeyUp
    };

    _browser.GetBrowser().GetHost().SendKeyEvent(k);

    Thread.Sleep(100);
}

特别感谢以下帖子:

• CefSharp网页元素单击
• 与CefSharp浏览器的SendKeys有关的问题
• CEF模拟鼠标按下和键盘发送

• CefSharp webpage element click
• Issue With CefSharp Browser SendKeys
• CEF Simulate Mousedown and Keysend