Getting an Error When Downloading a File

Question

Hello, I am making a launcher for a program I will be making in the near future.  It's supposed to 'check for updates' by downloading a file and checking if the version number in it matches the program's version.  If it does not match (update found), then it downloads the updated files and replaces them with the current program files.  I am stuck at the first part:  downloading the version file.  This is the line of code: 

My.Computer.Network.DownloadFile("<url>", "C:\version.txt")

There isn't a username and password.
This is the error I receive when this line executes: 

An unhandled exception of type 'System.Net.WebException' occurred in System.dll

Additional information: An exception occurred during a WebClient request.

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~ TechPerson32

Answer 1

TP32,

You don't need to "download" it (in the traditional sense), just read it directly:

    Private Function ReturnStringFromURL(ByVal url As String) As String
        Dim retVal As String
        Dim sb As New System.Text.StringBuilder
        Try
            Dim request As WebRequest = WebRequest.Create(url)
            Using response As HttpWebResponse = DirectCast(request.GetResponse, HttpWebResponse)
                Using dataStream As Stream = response.GetResponseStream
                    Using rdr As New StreamReader(dataStream)
                        sb.Append(rdr.ReadToEnd)
                    End Using
                End Using
            End Using
            retVal = sb.ToString
        Catch ex As Exception
            retVal = Nothing
        End Try
        Return retVal
    End Function

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Please call me Frank :)

Answer 2

Thank you!  :)

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~ TechPerson32

Answer 3

Hello Frank:

Maybe the result isn't a string, perhaps it's made up of binary things, so you cannot read directly:)

Hello TechPerson32:

Can you give us a detail Url for us to have a test with?

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Answer 4

Thank you!  :)

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~ TechPerson32

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Please call me Frank :)

Answer 5

Hello Frank:

Maybe the result isn't a string, perhaps it's made up of binary things, so you cannot read directly:)

Well he's saving it as a string:

My.Computer.Network.DownloadFile("<url>", "C:\version.txt")

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Please call me Frank :)

Answer 6

My.Computer.Network.DownloadFile("<url>", "C:\version.txt")

If version.txt already exists you need to set OVERWRITE to true.

http://msdn.microsoft.com/en-US/library/ms127881(v=vs.80).aspx