Trying to download a website to a file using WebClient DownloadFile works fine as long as I have a preset filename for it. If the filename is variable it throws an exception and I can't work out why.
dim link as string = "http://google.com"
Dim myWebClient As New System.Net.WebClient
myWebClient.DownloadFile(link, link & ".html")
If the output is set to "site.html" it'll work just fine but I can't get it to accept a variable.
I'm passing the variable link to the sub and I want it to save that site to The-Sitename.html. I'm guessing there is something really simple I'm missing here?
You cant save a file with the website extension included in the URL
Try using the following code to exclude common extensions to hopefully fix the issue
link = link.Replace("http://", "")
link = link.Replace("https://", "")
myWebClient.DownloadFile(link, link & ".html")
Related
I created a button and a menu item in vb.net (.NET 6). I found several answers here on SO that say the process to launching a webpage from such an event can be launched with this code:
Dim webAddress As String = "http://www.example.com/"
Process.Start(webAddress)
However, trying launch the code, I'm given the error of "system cannot find the file specified".
Looking more into it, I know that .NET 6 is running a bit differently and changed the code to the following:
Using link As New Process()
link.StartInfo.UseShellExecute = True
link.Start(New ProcessStartInfo("https://example.com"))
End Using
But still to no avail, and I am given the same error. "System cannot find the file specified." I can run addresses via the regular Windows Run prompt... but the program still cannot launch.
Following Jimi's comment to my original question, I changed the Sub to the following:
Sub LaunchWebsite(strWebpageURL As String)
Using Process.Start(New ProcessStartInfo(strWebpageURL) With {.UseShellExecute = True})
End Using
End Sub
Using this, the webpage launched in my desktop's default browser with no problem.
You can use
Respone.Redirect("http://www.example.com/")
or use javascript in server side code
Dim url As String = "http://www.example.com"
Dim s As String = "window.open('" & url + "', 'popup_window', 'width=300,height=100,left=100,top=100,resizable=yes');"
ClientScript.RegisterStartupScript(Me.GetType(), "script", s, True)
Above code open webpage in new popup window.
Regards
Aravind
how do I add a path to a code where "HERE_HAS_TO_BE_A_PATH" is. When I do, Im getting an error message. The goal is to be able to specific the path where is the final text file saved.
Thanks!
Here is a code:
Dim newFile As IO.StreamWriter = IO.File.CreateText("HERE_HAS_TO_BE_A_PATH")
Dim fix As String
fix = My.Computer.FileSystem.ReadAllText("C:\test.txt")
fix = Replace(fix, ",", ".")
My.Computer.FileSystem.WriteAllText("C:\test.txt", fix, False)
Dim query = From data In IO.File.ReadAllLines("C:\test.txt")
Let name As String = data.Split(" ")(0)
Let x As Decimal = data.Split(" ")(1)
Let y As Decimal = data.Split(" ")(2)
Let z As Decimal = data.Split(" ")(3)
Select name & " " & x & "," & y & "," & z
For i As Integer = 0 To query.Count - 1
newFile.WriteLine(query(i))
Next
newFile.Close()
1) Use a literal string:
The easiest way is replacing "HERE_HAS_TO_BE_A_PATH" with the literal path to desired output target, so overwriting it with "C:\output.txt":
Dim newFile As IO.StreamWriter = IO.File.CreateText("C:\output.txt")
2) Check permissions and read/write file references are correct:
There's a few reasons why you might be having difficulties, if you're trying to read and write into the root C:\ directory you might be having permissions issues.
Also, go line by line to make sure that the input and output files are correct every time you are using one or the other.
3) Make sure the implicit path is correct for non-fully qualified paths:
Next, when you test run the program, it's not actually in the same folder as the project folder, in case you're using a relative path, it's in a subfolder "\bin\debug", so for a project named [ProjectName], it compiles into this folder by default:
C:\path\to\[ProjectName]\bin\Debug\Program.exe
In other words, if you are trying to type in a path name as a string to save the file to and you don't specify the full path name starting from the C:\ drive, like "output.txt" instead of "C:\output.txt", it's saving it here:
C:\path\to\[ProjectName]\bin\Debug\output.txt
To find out exactly what paths it's defaulting to, in .Net Framework you can check against these:
Application.ExecutablePath
Application.StartupPath
4) Get user input via SaveFileDialogue
In addition to a literal string ("C:\output.txt") if you want the user to provide input, since it looks like you're using .Net Framework (as opposed to .Net Core, etc.), the easiest way to set a file name to use in your program is using the built-in SaveFileDialogue object in System.Windows.Forms (like you see whenever you try to save a file with most programs), you can do so really quickly like so:
Dim SFD As New SaveFileDialog
SFD.Filter = "Text Files|*.txt"
SFD.ShowDialog()
' For reuse, storing file path to string
Dim myFilePath As String = SFD.FileName
Dim newFile As IO.StreamWriter = IO.File.CreateText(myFilePath) ' path var
' Do the rest of your code here
newFile.Close()
5) Get user input via console
In case you ever want to get a path in .Net Core, i.e. with a console, the Main process by default accepts a String array called args(), here's a different version that lets the user add a path as the first parameter when running the program, or if one is not provided it asks the user for input:
Console.WriteLine("Hello World!")
Dim myFilePath = ""
If args.Length > 0 Then
myFilePath = args(0)
End If
If myFilePath = "" Then
Console.WriteLine("No file name provided, please input file name:")
While (myFilePath = "")
Console.Write("File and Path: ")
myFilePath = Console.ReadLine()
End While
End If
Dim newFile As IO.StreamWriter = IO.File.CreateText(myFilePath) ' path var
' Do the rest of your code here
newFile.Close()
6) Best practices: Close & Dispose vs. Using Blocks
In order to keep the code as similar to yours as possible, I tried to change only the pieces that needed changing. Vikyath Rao and Mary respectively pointed out a simplified way to declare it as well as a common best practice.
For more information, check out these helpful explanations:
Can any one explain why StreamWriter is an Unmanaged Resource. and
Should I call Close() or Dispose() for stream objects?
In summary, although streams are managed and should garbage collect automatically, due to working with the file system unmanaged resources get involved, which is the primary reason why it's a good idea to manually dispose of the object. Your ".close()" does this. Overrides for both the StreamReader and StreamWriter classes call the ".dispose()" method, however it is still common practice to use a Using .. End Using block to avoid "running with scissors" as Enigmativity puts it in his post, in other words it makes sure that you don't go off somewhere else in the program and forget to dispose of the open filestream.
Within your program, you could simply replace the "Dim newFile As IO.StreamWriter = IO.File.CreateText("C:\output.txt")" and "newFile.close()" lines with the opening and closing statements for the Using block while using the simplified syntax, like so:
'Dim newFile As IO.StreamWriter = IO.File.CreateText(myFilePath) ' old
Using newFile As New IO.StreamWriter(myFilePath) ' new
Dim fix As String = "Text from somewhere!"
newFile.WriteLine(fix)
' other similar operations here
End Using ' new -- ensures disposal
'newFile.Close() ' old
You can write that in this way. The stream writer automatically creates the file.
Dim newFile As New StreamWriter(HERE_HAS_TO_BE_A_PATH)
PS: I cannot mention all these in the comment section as I have reputations less than 50, so I wrote my answer. Please feel free to tell me if its wrong
regards,
vikyath
Hi people!
So right now I'm making a Minecraft Launcher, but I have a problem. I need to list every libraries in the .minecraft libraries folder, but the launcher can't access it even if it's executed as administrator.
Here is the code that fails :
Try
FileList = File.ReadAllLines(AppDataDir & "\libraries").ToList()
Catch ex As Exception
MsgBox(ex.Message)
End Try
The FileList variable :
Dim FileList As New List(Of String)
I need to make it a list of string because of this code :
Dim GameLibs As String = Nothing
For i = 0 To FileList.Count - 1
GameLibs += FileList.Item(i) + ";" + Environment.NewLine()
Next
So now I'm stuck with this problem, but I can't understand it since it works nicely with any other folder.
Oh and, the AppDataDir variable is just the .minecraft directory.
Any help would be great! Thanks if you tried to help me anyway.
I think you just missed the file name and its extension, try to add that line like this one:
FileList = File.ReadAllLines(AppDataDir & "\libraries.txt").ToList()
I hope that helps.
^_^
I am trying to copy the contents of an embedded file to a string in Visual Basic using Visual Studio 2013. I already have the resource (Settings.xml) imported and set as an embedded resource. Here is what I have:
Function GetFileContents(ByVal FileName As String) As String
Dim this As [Assembly]
Dim fileStream As IO.Stream
Dim streamReader As IO.StreamReader
Dim strContents As String
this = System.Reflection.Assembly.GetExecutingAssembly
fileStream = this.GetManifestResourceStream(FileName)
streamReader = New IO.StreamReader(fileStream)
strContents = streamReader.ReadToEnd
streamReader.Close()
Return strContents
End Function
When I try to save the contents to a string by using:
Dim contents As String = GetFileContents("Settings.xml")
I get the following error:
An unhandled exception of type 'System.ArgumentNullException' occurred in mscorlib.dll
Additional information: Value cannot be null.
Which occurs at line:
streamReader = New IO.StreamReader(fileStream)
Nothing else I've read has been very helpful, hoping someone here can tell me why I'm getting this. I'm not very good with embedded resources in vb.net.
First check fileStream that its not empty as it seems its contains nothing that's why you are getting a Null exception.
Instead of writing to file test it by using a msgBox to see it its not null.
fileStream is Nothing because no resources were specified during compilation, or because the resource is not visible to GetFileContents.
After fighting the thing for hours, I discovered I wasn't importing the resource correctly. I had to go to Project -> Properties -> Resources and add the resource from existing file there, rather than importing the file from the Solution Explorer. After adding the file correctly, I was able to write the contents to a string by simply using:
Dim myString As String = (My.Resources.Settings)
Ugh, it's always such a simple solution, not sure why I didn't try that first. Hopefully this helps someone else because I saw nothing about this anywhere else I looked.
I make a search program for searching a list of files in a computer and then copy the file into a store folder. The file name could be "*11*2.txt" As long as the program find this pattern, it should copy to the store folder. The problem is that I don't know the exactly name of the file before the search and I don't want to rename the file, I don't know how to save the file. Please help
I use the following to find the file, which does its work
Public Sub DirSearch(ByVal sDir As String, ByVal FileName As String)
Dim To_Path As String
To_Path = Form1.TextBox5.Text
For Each foundFile As String In My.Computer.FileSystem.GetFiles(sDir, FileIO.SearchOption.SearchAllSubDirectories, FileName)
Copy2Local(foundFile, To_Path)
Next
End Sub
Here is the current version of the Copy2Local (Note: it is not working right)
Public Sub Copy2Local(ByVal Copy_From_Path As String, ByVal Copy_To_Path As String)
' Specify the directories you want to manipulate.
Try
Dim fs As FileStream = File.Create(Copy_From_Path)
fs.Close()
' Copy the file.
File.Copy(Copy_From_Path, Copy_To_Path)
Catch
End Try
End Sub
First, you should check if ToPath is a valid directory since it's coming from a TextBox:
Dim isValidDir = Directory.Exists(ToPath)
Second, you can use Path.Combine to create a path from separate (sub)directories or file-names:
Dim copyToDir = Path.GetDirectoryName(Copy_To_Path)
Dim file = Path.GetFileName(Copy_From_Path)
Dim newPath = Path.Combine(copyToDir, file)
http://msdn.microsoft.com/en-us/library/system.io.path.aspx
(disclaimer: typed from a mobile)
To answer your question: You can get the file name with Path.GetFileName. Example:
Dim fileName As String = Path.GetFileName(foundFile)
However, there's a bunch of other things wrong with your code:
Here,
Dim fs As FileStream = File.Create(Copy_From_Path)
fs.Close()
you are overwriting your source file. This does not seem like a good idea. ;-)
And here,
Try
...
Catch
' Do Nothing
End Try
You are throwing away exceptions that would help you find and diagnose problems. Don't do that. It makes debugging a nightmare.
In vb.net, I'm using the following code to find the filename
Textbox1.Text = New FileInfo(OpenFileDialog.FileName).Name
this code work fine with open file dialog box