VB.NET 中的 HTTP GET

Question

在 VB.net 中发出 http get 的最佳方法是什么？我想得到像这样的请求的结果 http://api.hostip.info/?ip=68.180.206.184

Answer 1

在 VB.NET 中：

Dim webClient As New System.Net.WebClient
Dim result As String = webClient.DownloadString("http://api.hostip.info/?ip=68.180.206.184")

在 C# 中：

System.Net.WebClient webClient = new System.Net.WebClient();
string result = webClient.DownloadString("http://api.hostip.info/?ip=68.180.206.184");

Answer 2

您可以使用 HttpWebRequest 类执行请求并从给定 URL 检索响应。你会像这样使用它：

Try
    Dim fr As System.Net.HttpWebRequest
    Dim targetURI As New Uri("http://whatever.you.want.to.get/file.html")         

    fr = DirectCast(HttpWebRequest.Create(targetURI), System.Net.HttpWebRequest)
    If (fr.GetResponse().ContentLength > 0) Then
        Dim str As New System.IO.StreamReader(fr.GetResponse().GetResponseStream())
        Response.Write(str.ReadToEnd())
        str.Close(); 
    End If   
Catch ex As System.Net.WebException
   'Error in accessing the resource, handle it
End Try

HttpWebRequest 的详细信息位于： http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx

第二种选择是使用 WebClient 类，它提供了一个更易于使用的接口来下载 Web 资源，但不如 HttpWebRequest 灵活：

Sub Main()
    'Address of URL
    Dim URL As String = http://whatever.com
    ' Get HTML data
    Dim client As WebClient = New WebClient()
    Dim data As Stream = client.OpenRead(URL)
    Dim reader As StreamReader = New StreamReader(data)
    Dim str As String = ""
    str = reader.ReadLine()
    Do While str.Length > 0
        Console.WriteLine(str)
        str = reader.ReadLine()
    Loop
End Sub

有关网络客户端的更多信息，请访问： http://msdn.microsoft.com/en-us/library/system.net.webclient.aspx

Answer 3

使用 网络请求 班级

这是为了获取图像：

Try
    Dim _WebRequest As System.Net.WebRequest = Nothing
    _WebRequest = System.Net.WebRequest.Create(http://api.hostip.info/?ip=68.180.206.184)
Catch ex As Exception
    Windows.Forms.MessageBox.Show(ex.Message)
    Exit Sub
End Try

Try
    _NormalImage = Image.FromStream(_WebRequest.GetResponse().GetResponseStream())
Catch ex As Exception
    Windows.Forms.MessageBox.Show(ex.Message)
    Exit Sub
End Try

Answer 4

最简单的方法是 System.Net.WebClient.DownloadFile 或者 DownloadString.

Answer 5

你应该尝试 HttpWeb请求 班级。

Answer 6

尝试这个：

WebRequest request = WebRequest.CreateDefault(RequestUrl);
request.Method = "GET";

WebResponse response;
try { response = request.GetResponse(); }
catch (WebException exc) { response = exc.Response; }

if (response == null)
    throw new HttpException((int)HttpStatusCode.NotFound, "The requested url could not be found.");

using(StreamReader reader = new StreamReader(response.GetResponseStream())) {
    string requestedText = reader.ReadToEnd();

    // do what you want with requestedText
}

抱歉，关于 C#，我知道您要求使用 VB，但我没有时间转换。

Answer 7

Public Function getLoginresponce(ByVal email As String, ByVal password As String) As String
    Dim requestUrl As String = "your api"
    Dim request As HttpWebRequest = TryCast(WebRequest.Create(requestUrl), HttpWebRequest)
    Dim response As HttpWebResponse = TryCast(request.GetResponse(), HttpWebResponse)
    Dim dataStream As Stream = response.GetResponseStream()
    Dim reader As New StreamReader(dataStream)
    Dim responseFromServer As String = reader.ReadToEnd()
    Dim result = responseFromServer
    reader.Close()
    response.Close()
    Return result
End Function