CefGlue中js与C#交互（实现mp3播放）

一、C#调用js

1.通过CefFrame.ExecuteJavaScript(string code, string url, int line)方法执行JS

private void browser_LoadEnd(object sender, Xilium.CefGlue.WPF.LoadEndEventArgs e)
        {
            browser.ExecuteJavaScript("window.iscef = true;", browser.GetCefBrowser().GetMainFrame().Url, 0);
        }

2.通过CefV8Value.ExecuteFunction或CefV8Value.ExecuteFunctionWithContext执行

二、js调用C#

1.定义DemoRenderProcessHandler，继承自CefRenderProcessHandler，重写OnWebKitInitialized事件，根据实际情况，人工手写JS脚本代码，通过官方提供的RegisterExtension(string extensionName, string javascriptCode, CefV8Handler handler)方法进行注册：

 public class DemoRenderProcessHandler : CefRenderProcessHandler
    {
        private TGCefV8Handler tgCefV8Handler;
        protected override void OnWebKitInitialized()
        {
            tgCefV8Handler = new TGCefV8Handler();

            const string exampleAJavascriptCode = @"function tgCefV8Handler() {}
    if (!tgCefV8Handler) tgCefV8Handler = {};
    (function() {
        tgCefV8Handler.playMp3 = function(arg0) {
            native function PlayMp3(arg0);
            return PlayMp3(arg0);
        };
    })();";

            CefRuntime.RegisterExtension("exampleAExtensionName", exampleAJavascriptCode, tgCefV8Handler);

            base.OnWebKitInitialized();
        }
    }

2.定义一个CefV8Handler，继承自CefV8Handler，在ExampleAv8Handler里的Execute事件中，写你要执行的操作代码，下面代码中的JSFunc.PlayMp3表示一个播放mp3的函数

public class TGCefV8Handler : CefV8Handler
    {
        /// <summary>
        /// 默认构造函数
        /// </summary>
        public TGCefV8Handler()
        {
        }


        protected override bool Execute(string name, CefV8Value obj, CefV8Value[] arguments, out CefV8Value returnValue, out string exception)
        {
            string result = string.Empty;

            switch (name)
            {
                case "PlayMp3":
                    result = JSFunc.PlayMp3(arguments[0].GetStringValue());
                    break;
                default:
                    break;
            }

            returnValue = CefV8Value.CreateString(result);
            exception = null;
            return true;
        }
    }

3.在CefApp中重写GetRenderProcessHandler方法：

internal sealed class SampleCefApp : CefApp
    {
        public SampleCefApp()
        {
        }

        private CefRenderProcessHandler _renderProcessHandler = new DemoRenderProcessHandler();

        protected override void OnBeforeCommandLineProcessing(string processType, CefCommandLine commandLine)
        {
            if (string.IsNullOrEmpty(processType))
            {
                commandLine.AppendSwitch("disable-gpu");
                commandLine.AppendSwitch("disable-gpu-compositing");
                commandLine.AppendSwitch("enable-begin-frame-scheduling");
                commandLine.AppendSwitch("disable-smooth-scrolling");
            }
        }

        protected override CefRenderProcessHandler GetRenderProcessHandler()
        {
            return _renderProcessHandler;
        }
    }

4.最后在js中调用方式为：

var msg = window.tgCefV8Handler.playMp3(url);