如何从另一个 class c# 获取异常

Question

我有这些class

//Class 1, ViewModel
    public async System.Threading.Tasks.Task<JObject> ExecuteSystemObject(string parameters)
    {    
        ...
        dynamic j = await ExternalProject.ExecuteSomething<MyModel>(parameters);
        //How i can catch the error from the another class?
        ...
    }

//Class2, Manager
    public async Task<Object> ExecuteSomething<T>() where T : IModel, new()
    {
        ...
        WebResponse response = await ExternalProject.ExecuteRequestAsync(PostRequest);
        ...
    }

//Class 3, from a binding Project 
    public static async Task<WebResponse> ExecuteRequestAsync(WebRequest request)
    {
        try
        {
            return await request.GetResponseAsync();
        }
        catch(WebException e)
        {
            var resp = new StreamReader(e.Response.GetResponseStream()).ReadToEnd();
            dynamic obj = JsonConvert.DeserializeObject(resp);
            //I have the message error here
            var messageFromServer = obj.error.text;
            throw e;
        }
    }

我只能在最后一个 class 中得到错误，如果我尝试在另一个中得到 WebException，它将对我来说 return null。然后，我如何将该错误传递给主要 class(1º one, ViewModel)?

Answer 1

只要您想要重新抛出异常以便能够保留堆栈跟踪，请始终使用 throw;。

public async System.Threading.Tasks.Task<JObject> ExecuteSystemObject(string parameters)
{    
    try 
    {
        dynamic j = await ExternalProject.ExecuteSomething<MyModel>(parameters);
        //How i can catch the error from the another class?
        ...
    }
    catch(Exception e)
    {
        //WebException will be caught here
    }
}

public async Task<Object> ExecuteSomething<T>() where T : IModel, new()
{
    try 
    {
        WebResponse response = await ExternalProject.ExecuteRequestAsync(PostRequest);
    }
    catch(Exception)
    {
        throw;
    }

}

public static async Task<WebResponse> ExecuteRequestAsync(WebRequest request)
{
    try
    {
        //return await request.GetResponseAsync();
        throw new WebException("Test error message");
    }
    catch(WebException e)
    {
        throw;
    }
}

编辑：只是一条经验法则，只有在您需要处理异常时才捕获异常。如果您正在捕获异常只是为了记录它。不要这样做。

如何从另一个 class c# 获取异常

How to get an Exception from another class c#

c#

system.net.webexception