错误处理HTTPWebRequests，VB.NET

Question

我环顾四周，无法找到答案，所以我想我会问这里。 我有一个程序调用一个API，并在头文件中传递登录信息，服务器在身份验证时返回一些信息。问题是如果用户信用不正确，程序崩溃并抛出异常。这个错误是401.它如何捕捉这个并告诉用户？ 我的代码是：

Dim request = TryCast(System.Net.WebRequest.Create("https://myurl.com"), System.Net.HttpWebRequest) 

    request.Method = "GET" 

    request.Headers.Add("authorization", "Bearer " + AccessToken) 

    request.ContentLength = 0 
    Dim responseContent As String 
    Using response = TryCast(request.GetResponse(), System.Net.HttpWebResponse) 
     Using reader = New System.IO.StreamReader(response.GetResponseStream()) 
      responseContent = reader.ReadToEnd() 
      MessageBox.Show(responseContent) 
     End Using 
    End Using 

感谢。

Answer 1

使用try catch语句

try 
    'My error prone code 
catch ex as Exception 
    'Handle my error 
end try 

---

Try 

     Dim request = TryCast(System.Net.WebRequest.Create("https://myurl.com"), System.Net.HttpWebRequest) 

     request.Method = "GET" 

     request.Headers.Add("authorization", "Bearer " + AccessToken) 

     request.ContentLength = 0 
     Dim responseContent As String 
     Using response = TryCast(request.GetResponse(), System.Net.HttpWebResponse) 
      Using reader = New System.IO.StreamReader(response.GetResponseStream()) 
       responseContent = reader.ReadToEnd() 
       MessageBox.Show(responseContent) 
      End Using 
     End Using 

    Catch ex As Exception 
     MessageBox.Show(ex.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) 
    End Try