任何人都可以使用示例客户端应用程序解释IExceptionHandler的工作流程

我在本示例中面临以下问题：

我无法在ExceptionContext找到IsOutermostCatchBlock

如果发生exception，则此HandleAsync方法正在执行两次。

（ http://www.asp.net/web-api/overview/web-api-routing-and-actions/web-api-global-error-handling ）

 public class CustomExceptionHandler : IExceptionHandler { public virtual Task HandleAsync(ExceptionHandlerContext context, CancellationToken cancellationToken) { if (!ShouldHandle(context)) { return Task.FromResult(0); } return HandleAsyncCore(context, cancellationToken); } public virtual Task HandleAsyncCore(ExceptionHandlerContext context, CancellationToken cancellationToken) { HandleCore(context); return Task.FromResult(0); } public virtual void HandleCore(ExceptionHandlerContext context) { } public virtual bool ShouldHandle(ExceptionHandlerContext context) { return context.ExceptionContext.IsOutermostCatchBlock; } } public class OopsExceptionHandler : CustomExceptionHandler { public override void HandleCore(ExceptionHandlerContext context) { context.Result = new TextPlainErrorResult { Request = context.ExceptionContext.Request, Content = "Oops! Sorry! Something went wrong." + "Please contact [e-mail] so we can try to fix it." }; } private class TextPlainErrorResult : IHttpActionResult { public HttpRequestMessage Request { get; set; } public string Content { get; set; } public Task ExecuteAsync(CancellationToken cancellationToken) { HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.InternalServerError); response.Content = new StringContent(Content); response.RequestMessage = Request; return Task.FromResult(response); } } } } 

Answer 1

CatchBlock.IsTopLevel

IsOutermostCatchBlock不存在。 改为使用CatchBlock.IsTopLevel ：

 public virtual bool ShouldHandle(ExceptionHandlerContext context) { return context.ExceptionContext.CatchBlock.IsTopLevel; } 

NuDoq上的源： ExceptionHandlerContext和ExceptionContextCatchBlock