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TitleValidate a URL in Visual Basic .NET
DescriptionThis example shows how to validate a URL in Visual Basic .NET.
Keywordsvalidate URL, URL, VB.NET
CategoriesVB.NET, Utilities, Internet
 
The UrlIsValid function creates an HttpWebRequest object and calls its GetResponse method to see if the URL points to a Web page. If it is successful, the function returns True.

Note that the Finally block closes the HttpWebResponse. If the code doesn't do this, your system may use up all of its connections and further requests get stuck. To see this, comment out the Close statement and use the program to validate several URLs.

 
Private Function UrlIsValid(ByVal url As String) As Boolean
    Dim is_valid As Boolean = False
    If url.ToLower().StartsWith("www.") Then url = _
        "http://" & url

    Dim web_response As HttpWebResponse = Nothing
    Try
        Dim web_request As HttpWebRequest = _
            HttpWebRequest.Create(url)
        web_response = _
            DirectCast(web_request.GetResponse(), _
            HttpWebResponse)
        Return True
    Catch ex As Exception
        Return False
    Finally
        If Not (web_response Is Nothing) Then _
            web_response.Close()
    End Try
End Function
 
This example is based on the DevX tip Determine Whether a URL Is Valid. I have made some changes to simplify it and added the code to close the response.
 
 
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