Search on twitter

Imports System.Xml
Imports System.Web

Public Class Form1
    Private Structure struct_Tweet
        Public guid As String
        Public Title As String
        Public link As String
        Public description As String
        Public pubDate As String
        Public enclosure As String
        Public category As String
    End Structure

    Private Tweets As List(Of struct_Tweet)

    Private mUrl_Search As String = "http://www.queryfeed.net/twitter?q="
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Tweets = New List(Of struct_Tweet)

        'Process("shadowtzu")
        Process("#gamedev")
        '100 is maximum
        If Tweets.Count > 0 Then
            MsgBox("Result Count: " & Tweets.Count & vbCrLf _
                & "Last Tweet: " & vbCrLf _
               & "User: " & Tweets(0).Title & vbCrLf _
                & "Date: " & Tweets(0).pubDate & vbCrLf _
                & "Text: " & Tweets(0).description)
        End If


    End Sub

    Private Sub Process(Search As String)
        'Dim SDate As DateTime = Date.Now.AddDays(-1)
      '  Dim Since As String = "since:" & SDate.Year & "-" & SDate.Month & "-" & SDate.Day
        Dim doc As New XmlDocument()
        Dim HasError As Boolean = False
        Do
            Try
                doc.Load(Url_Search(Search)) ' & " " & Since
                HasError = False
            Catch ex As Exception
                HasError = True
            End Try
        Loop While HasError = True


        For Each MainNode As XmlNode In doc.ChildNodes
            For Each rss As XmlNode In MainNode
                If rss.Name = "channel" AndAlso rss.HasChildNodes Then
                    For Each Child As XmlNode In rss.ChildNodes
                        If Child.Name = "item" AndAlso Child.HasChildNodes Then
                            Dim NewTweet As struct_Tweet = Nothing
                            With NewTweet
                                If Not Child("guid") Is Nothing Then .guid = Child("guid").InnerText
                                If Not Child("title") Is Nothing Then .Title = Child("title").InnerText
                                If Not Child("link") Is Nothing Then .link = Child("link").InnerText
                                If Not Child("description") Is Nothing Then .description = Child("description").InnerText
                                If Not Child("pubDate") Is Nothing Then .pubDate = Child("pubDate").InnerText
                                If Not Child("enclosure") Is Nothing Then .enclosure = ReadTag(Child("enclosure"), "url")
                                If Not Child("category") Is Nothing Then .category = Child("category").InnerText
                            End With
                            Tweets.Add(NewTweet)
                        End If
                    Next
                End If
            Next
        Next

    End Sub

    Private Function Url_Search(Search As String) As String
        Return mUrl_Search & URLEncode(Search) & "&geocode="
    End Function

    Private Function ReadTag(Node As XmlNode, Tag As String, Optional DefaultValue As String = "") As String
        If Not Node.Attributes Is Nothing Then

            If Not Node.Attributes(Tag) Is Nothing Then
                Return Node.Attributes(Tag).Value
            Else
                Return DefaultValue
            End If
        Else
            Return DefaultValue
        End If
    End Function

    Public Function URLEncode(StringToEncode As String) As String
        Return HttpUtility.UrlEncode(StringToEncode)
    End Function

End Class