吐槽一下，博客园久了没有上，账号没了，重新申请一个.
cesharp v62版本，内核采用最新的Cef 62，支持最新的Grid布局. 由于官方的cefsharp 采用.net4.5.2开发.怎么办怎么办.我只能用.net4.0.没办法啊，自己拿源码修改兼容呗.
仔细分析源码发现：
1.net4.5.2 引入了 async/await 关键字. 这个其实国外大神已经有源码放出来了，我们把代码直接引入cefsharp 这个工程. 就可以直接在4.0里使用 async/await;
2.net4.5 对task api 做了扩展， 我们只需要在.net4.0实现一下对应的api.就可以了.
3. 源码里面用了很多4.5才有的GetTypeInfo 扩展方法错误. 它返回的类型是typeinfo，不用管它，把GetTypeInfo 删掉. 直接Type 调用就可以了.
4. 对Task静态方法的扩展，需要修改一下，静态方法的调用方式.
以上是要点.下面贴源码：
本段源码是对：async/await的支持：
namespace System.Threading.Tasks { public static class TaskEx { public static TaskAwaiter GetAwaiter(this Task task) { return new TaskAwaiter(task); } public static TaskAwaiter<T> GetAwaiter<T>(this Task<T> task) { return new TaskAwaiter<T>(task); } } public struct TaskAwaiter : INotifyCompletion { readonly Task task; internal TaskAwaiter(Task task) { this.task = task; } internal static TaskScheduler TaskScheduler { get { if (SynchronizationContext.Current == null) return TaskScheduler.Default; else return TaskScheduler.FromCurrentSynchronizationContext(); } } public bool IsCompleted { get { return task.IsCompleted; } } public void OnCompleted(Action continuation) { this.task.ContinueWith( delegate (Task task) { continuation(); }, TaskAwaiter.TaskScheduler); } public void GetResult() { try { task.Wait(); } catch (AggregateException ex) { throw ex.InnerExceptions[0]; } } } public struct TaskAwaiter<T> : INotifyCompletion { readonly Task<T> task; internal TaskAwaiter(Task<T> task) { this.task = task; } public bool IsCompleted { get { return task.IsCompleted; } } public void OnCompleted(Action continuation) { this.task.ContinueWith( delegate (Task<T> task) { continuation(); }, TaskAwaiter.TaskScheduler); } public T GetResult() { try { return task.Result; } catch (AggregateException ex) { throw ex.InnerExceptions[0]; } } } } namespace System.Runtime.CompilerServices { public interface INotifyCompletion { void OnCompleted(Action continuation); } public interface ICriticalNotifyCompletion : INotifyCompletion { [SecurityCritical] void UnsafeOnCompleted(Action continuation); } public interface IAsyncStateMachine { void MoveNext(); void SetStateMachine(IAsyncStateMachine stateMachine); } public struct AsyncVoidMethodBuilder { public static AsyncVoidMethodBuilder Create() { return new AsyncVoidMethodBuilder(); } public void SetException(Exception exception) { throw exception; } public void SetResult() { } public void SetStateMachine(IAsyncStateMachine stateMachine) { // Should not get called as we don't implement the optimization that this method is used for. throw new NotImplementedException(); } public void Start<TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine { stateMachine.MoveNext(); } public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } } public struct AsyncTaskMethodBuilder { TaskCompletionSource<object> tcs; public Task Task { get { return tcs.Task; } } public static AsyncTaskMethodBuilder Create() { AsyncTaskMethodBuilder b; b.tcs = new TaskCompletionSource<object>(); return b; } public void Start<TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine { stateMachine.MoveNext(); } public void SetStateMachine(IAsyncStateMachine stateMachine) { // Should not get called as we don't implement the optimization that this method is used for. throw new NotImplementedException(); } public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void SetResult() { tcs.SetResult(null); } public void SetException(Exception exception) { tcs.SetException(exception); } } public struct AsyncTaskMethodBuilder<T> { TaskCompletionSource<T> tcs; public Task<T> Task { get { return tcs.Task; } } public static AsyncTaskMethodBuilder<T> Create() { AsyncTaskMethodBuilder<T> b; b.tcs = new TaskCompletionSource<T>(); return b; } public void Start<TStateMachine>(ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine { stateMachine.MoveNext(); } public void SetStateMachine(IAsyncStateMachine stateMachine) { // Should not get called as we don't implement the optimization that this method is used for. throw new NotImplementedException(); } public void AwaitOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine { awaiter.OnCompleted(stateMachine.MoveNext); } public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine>(ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine { AwaitOnCompleted(ref awaiter, ref stateMachine); } public void SetResult(T result) { tcs.SetResult(result); } public void SetException(Exception exception) { tcs.SetException(exception); } } }
这段是对 Task 的扩展