可以，参考

Select Case e.Path
    Case "test.htm", ""
        msgbox(e.request.UserAgent )
        Dim agent As String = e.request.UserAgent
        If agent.contains("MicroMessenger") Then
            msgbox("微信")
        Else
            Dim flag As Boolean = False
            Dim keywords As String() = {"Android", "iPhone", "iPod", "iPad", "Windows Phone", "MQQBrowser"}
            \'排除 Windows 桌面系统
            If Not agent.Contains("Windows NT") OrElse (agent.Contains("Windows NT") AndAlso agent.Contains("compatible; MSIE 9.0;")) Then
                \'排除 苹果桌面系统
                If Not agent.Contains("Windows NT") AndAlso Not agent.Contains("Macintosh") Then
                    For Each item As String In keywords
                        If agent.Contains(item) Then
                            msgbox(item)
                            flag = True
                            Exit For
                        End If
                    Next
                End If
            End If
            If flag Then
                msgbox("手机")
            Else
                msgbox("电脑")
            End If
        End If
End Select

https://docs.microsoft.com/zh-cn/dotnet/api/system.net.httplistenerrequest?redirectedfrom=MSDN&view=netframework-4.7.2

判断是不是微信里打开的。你也可以删除。