从URL到文本框的VB.Net JSON如何处理错误? [英] VB.Net JSON From URL To Textbox How Can I Handle Errors?

问题描述

我的JSON字符串返回了

My JSON String Returned

{

"name": "username",
"place": {
  "name": "placename",
}    

当下我的代码

    Dim request As HttpWebRequest
    Dim response As HttpWebResponse = Nothing
    Dim reader As StreamReader

    Try

        request = DirectCast(WebRequest.Create("http://my-json.com/json"), HttpWebRequest)

        response = DirectCast(request.GetResponse(), HttpWebResponse)
        reader = New StreamReader(response.GetResponseStream())

        Dim rawresp As String
        rawresp = reader.ReadToEnd()

        Dim jResults As JObject = JObject.Parse(rawresp)
        usernameTextbox.text = jResults("name").ToString()
        placenameTextbox.text = jResults("place")("name").ToString()

    Catch ex As Exception
        MsgBox(ex.ToString)
    Finally
        If Not response Is Nothing Then response.Close()

    End Try

但是当我遇到类似404的错误时，我会得到一个异常

But when i get an error like 404 i get an exception

system.net.webexception: The server returned an error (404) Not Found.

这发生在行

response = DirectCast(request.GetResponse(), HttpWebResponse)

请您告知我如何处理此错误并将消息输出到消息框

please could you advise me on how i can handle this error and output a message to a messagebox

谢谢

推荐答案

似乎我必须更改

    Catch ex As Exception
    MsgBox(ex.ToString)
Finally

收件人

Catch ex As System.Net.WebException
        MsgBox(ex.ToString)
Finally

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