我是vb.net和asp.net的新手。我正在尝试更新Page_Load中的asp:标签。标签的值来自所有Webservice。
vb.net代码:
Protected Sub Page_Load(ByVal sender As Object,ByVal e As System.EventArgs) Handles Me.Load
If Not Page.IsPostBack Then lblMaxValue.Text = " Value is: " & GetRequestResponse(URL)
服务代码:
Private Sub GetRequestResponse(uri As Uri,callback As action(Of String))
servicepointManager.SecurityProtocol = SecurityProtocolType.Tls12
Dim request As HttpWebRequest = DirectCast(HttpWebRequest.Create(uri),HttpWebRequest)
request.Method = "GET"
request.ContentType = "application/json"
request.BeginGetResponse(
Function(x)
Using response As Httpwebresponse = DirectCast(request.EndGetResponse(x),Httpwebresponse)
If callback Isnot Nothing Then
Dim reader As New StreamReader(response.GetResponseStream())
Dim streamText As String = reader.ReadToEnd()
callback(streamText)
End If
End Using
Return 1
End Function,Nothing)
End Sub
没有错误,但值没有更新。