I am new here, and relatively new to VB.NET. I have a specific problem with getting my StreamWriter to work properly. One of the requirements of my project is to give the file a default name when the user clicks the Save button, which I have done by setting mysave.Filename = "MyLog.log". I call a new instance of my streamwriter trying to save to the filename specified by the user (mySave.Filename again), but every time, it saves to the default MyLog.log file. I have pasted my code below.
If someone could tell me how I can make sure the data is being saved to the value entered by the user for File name, that would be greatly beneficial. Also, I apologize for the code format, its not perfectly readable, but I'm trying to learn how to use the 4 space indents to my advantage!!
Thanks!
Imports System.IO
Public Class Form1
Dim Initial As String = "C:\Users\Brian Frick\Documents\Visual Studio 2010\Projects\HW5_Frick_Creator\HW5_Frick_Creator\bin\Debug" 'give variable for full path without log file
Dim Fullpath As String = "C:\Users\Brian Frick\Documents\Visual Studio 2010\Projects\HW5_Frick_Creator\HW5_Frick_Creator\bin\Debug\MyLog.log" 'give one path for full path
Dim filewriter As New StreamWriter(Fullpath, True)
Private Sub ExitToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExitToolStripMenuItem.Click
Application.Exit() ' quit application
filewriter.Close()
End Sub
Private Sub SaveToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SaveToolStripMenuItem.Click
Dim mySave As New SaveFileDialog
mySave.Filter = "LOG File (*.log)|*.log" 'set filter to .log
mySave.DefaultExt = "log" 'set default extension
mySave.InitialDirectory = Initial 'set default directory
mySave.FileName = "MyLog.log"
mySave.OverwritePrompt = True ' make sure to ask user if they want to over write
If mySave.ShowDialog() = DialogResult.OK Then
Dim filewriter As New StreamWriter(mySave.FileName, True)
filewriter.Close()
'filewriter = New StreamWriter(mySave.FileName, True)
'filewriter.Close() 'close filewriter to allow access to write directory
'Dim Stream As New StreamWriter(mySave.FileName, True) 'save file to path chosen by user in SaveDialog
'Stream.Close() ' Close stream to allow access to directory
' filewriter.Close()
Else
'dialog cancelled - no action
End If
filewriter.Close()
filewriter = New StreamWriter(Fullpath, True) 're initiate filewriter to be used in successive iterations through the program without error
End Sub
Private Sub SavingsDepositBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SavingsDepositBtn.Click
'write to file for SavDep
filewriter.WriteLine("SavDep")
filewriter.WriteLine(AccountBox.Text)
filewriter.WriteLine(AmountBox.Text)
End Sub
Private Sub SavingsWithdrawBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SavingsWithdrawBtn.Click
'write to file for SavWith
filewriter.WriteLine("SavWith")
filewriter.WriteLine(AccountBox.Text)
filewriter.WriteLine(AmountBox.Text)
End Sub
Private Sub CheckDepsotBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckDepsotBtn.Click
'write to file for CheckDep
filewriter.WriteLine("CheckDep")
filewriter.WriteLine(AccountBox.Text)
filewriter.WriteLine(AmountBox.Text)
End Sub
Private Sub CheckWithdrawBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckWithdrawBtn.Click
'write to file for CheckWith
filewriter.WriteLine("CheckWith")
filewriter.WriteLine(AccountBox.Text)
filewriter.WriteLine(AmountBox.Text)
End Sub
End Class
the general way you are using the filewriter won't work, and there are some other serious issues like that there are two 'FileWriter' variables with overlapping scope.
for your save routine, you can't just re-instantiate your filewriter to point it to a different path. that will destroy all the data that had been in the underlying stream, so you are just saving nothing.
try caching the data in memory while the program is running, and don't create the stream until you are ready to write all the data to it, and it to a file, all in one go. your current approach makes it very hard to prevent leaking handles to the log files, so if the app crashes the user will have to reboot to release the write lock before they can run it again. look into the 'using' construct and 'Try... Finally'
Related
I am creating a form that will prompt the user to enter a file name upon loading the file. The issue I encounter is that my variable I use to store the input is not recognized in another one of my procedures. The code here shows my current set up.
Imports System.IO
Public Class frmEmployee
Sub frmEmployee_load(ByVal sender As Object, e As System.EventArgs)
Dim strFileName = InputBox("Please name the file you would like to save the data to: ")
End Sub
Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
txtEmail.Clear()
txtExtension.Clear()
txtFirst.Clear()
txtLast.Clear()
txtMiddle.Clear()
txtNumber.Clear()
txtPhone.Clear()
End Sub
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
Dim inputFile As New StreamWriter(strFileName)
If File.Exists(strFileName) = True Then
inputFile = File.CreateText(strFileName)
inputFile.Write(txtEmail.Text)
inputFile.Write(txtExtension.Text)
inputFile.Write(txtFirst.Text)
inputFile.Write(txtLast.Text)
inputFile.Write(txtMiddle.Text)
inputFile.Write(txtNumber.Text)
inputFile.Write(txtPhone.Text)
inputFile.Write(cmbDepart.Text)
Else
MessageBox.Show("" & strFileName & "Cannot be created or found.")
End If
End Sub
Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
Me.Close()
End Sub
End Class
The load event handler is where I want the user to input the name of the file.
Change the scope of your variable to outside of your load method...
Public Class frmEmployee
Private strFileName As String
Sub frmEmployee_load(ByVal sender As Object, e As System.EventArgs)
strFileName = InputBox("Please name the file you would like to save the data to: ")
End Sub
You could use My.Settings and load the file string there and save it. All forms can now access that. When you close the the app set it to String.Empty if you want it to be.
You also could be taking advantage of a class object for the fields you are capturing then using either BinaryFormatter or XmlSerializer to store the data. Better databinding, creation and reconstruction using an object.
My.Settings.Filename = Inputbox("Filename?")
My.Settings.Save()
The problem with the approach you have there is that your variabl strFileName is scoped to the class frmEmployee.
You need to set up a genuinely global variable (at the application startup) an then use that. So you will need a Sub Main as an entry point to your application See here, and just before that create a public variable to hole the file name.
So you might have something like this for your application startup:
Public fileNametoUse as string
Public Sub Main()
Application.EnableVisualStyles()
Application.SetCompatibleTextRenderingDefault(False)
Application.Run(New Form1)
End Sub
Then in you load sub for frmEmployee you would have:
fileNametoUse = InputBox("Please name the file you would like to save the data to: ")
I'm navigating from webbrowser control to an url like this;
http://www.who.int/cancer/modules/Team%20building.pdf
It's shown in webbrowser control. What I want to do is to download this pdf file to computer. But I tried many ways;
Dim filepath As String
filepath = "D:\temp1.pdf"
Dim client As WebClient = New WebClient()
client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted);
client.DownloadFileAsync(WebBrowserEx1.Url, filepath)
This one downloads a pdf but there is nothing in the file.
Also tried with
objWebClient.DownloadFile()
nothing changed.
I tried to show a save or print dialog;
WebBrowserEx1.ShowSaveAsDialog()
WebBrowserEx1.ShowPrintDialog()
but they didnt show any dialog. Maybe the last one is because it doesnt wait to load the the pdf into webbrowser completely.
When I try html files there is no problem to dowload, but in this .pdf file, I think I didn't manage to wait the file to be loaded as pdf into browser. This function(s);
Private Sub WaitForPageLoad(ByVal adimno As String)
If adimno = "1" Then
AddHandler WebBrowserEx1.DocumentCompleted, New WebBrowserDocumentCompletedEventHandler(AddressOf PageWaiter)
While Not pageReady
Application.DoEvents()
End While
pageReady = False
End If
End Sub
Private Sub PageWaiter(ByVal sender As Object, ByVal e As WebBrowserDocumentCompletedEventArgs)
If WebBrowserEx1.ReadyState = WebBrowserReadyState.Complete Then
pageReady = True
RemoveHandler WebBrowserEx1.DocumentCompleted, New WebBrowserDocumentCompletedEventHandler(AddressOf PageWaiter)
End If
End Sub
are not working for this situation. I mean it gets into infinite loop.
So anyone knows how to wait this to load pdf then save into computer.
you could test the URL when document completed fires and if its .pdf, then do the following then navigate back, for example.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
WebBrowserEx1.Navigate("http://www.who.int/cancer/modules/Team%20building.pdf")
End Sub
Private Sub WebBrowserEx1_DocumentCompleted(ByVal sender As Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) Handles WebBrowserEx1.DocumentCompleted
If WebBrowserEx1.Url.ToString.Contains(".pdf") Then
Using webClient = New WebClient()
Dim bytes = webClient.DownloadData(WebBrowserEx1.Url.ToString) 'again variable here
File.WriteAllBytes(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "TEST.pdf"), bytes) 'save to desktop or specialfolder. to list all the readily available user folders
End Using
'WebBrowserEx1.goback() 'could send browser back a page as well
End If
End Sub
You will need to make the filename "TEST" as a variable instead of a static string or else you will overwrite the same file each time. Perhaps:
WebBrowserEx1.DocumentTitle.ToString & ".pdf"
instead, which would save the file as pdf named by the webpage title. Only problem there is if the page contains illegal characters (that windows doesnt let you save with) it will throw an exception so that should be handled.
Hi can anyone tell me why the following dose not work:
(p.s I dont want the file to append upon clicking abutton just upon clicking the checkbox.
Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
Dim FILE_NAME As String = "C:\RXF\log.txt"
'Adding items for AutoCAD 2006...
If CheckBox1.CheckState = CheckState.Checked Then
Dim objWriter As New System.IO.StreamWriter(FILE_NAME, True)
objWriter.WriteLine("module: 4FNV-67-5H")
objWriter.Close()
End If
End Sub
End Class
Not reproducible, even with your exact code as posted. This works perfectly fine for me, creating a text file in the specified location if one does not exist and appending the specified text to the end of the file.
The only thing I suggest is wrapping your StreamWriter object in a Using statement to ensure that its Dispose method always gets called, even if an exception is thrown (which is all the more likely when you're doing disk I/O). So, your existing code would simply change to:
Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
Dim FILE_NAME As String = "C:\RXF\log.txt"
''#Adding items for AutoCAD 2006...
If CheckBox1.CheckState = CheckState.Checked Then
Using objWriter as New System.IO.StreamWriter(FILE_NAME, True)
objWriter.WriteLine("module: 4FNV-67-5H")
objWriter.Close()
End Using
End If
End Sub
Also, if you anticipate this method getting called a lot (i.e., the user clicking and unclicking and clicking the checkbox repeatedly), you might consider creating the StreamWriter object once and saving it as a private class-level variable, instead of creating and disposing of it each time the method is called. Then you just have to make sure that you dispose of it whenever your class (presumably the containing form) is disposed.
I am new to Visual Basic.NET and I am just playing around with it. I have a book that tells me how to read from a file but not how to write to the file with a button click. All I have is a button and a textbox named fullNameBox. When I click the button it gives me an unhandled exception error. Here is my code:
Public Class Form1
Sub outputFile()
Dim oWrite As System.IO.StreamWriter
oWrite = System.IO.File.CreateText("C:\sample.txt")
oWrite.WriteLine(fullNameBox.Text)
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
outputFile()
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
End Class
Have you tried stepping through your application to see where the error is? With a quick glance, it looks like you might need to use System.IO.File on the fourth line (oWrite = IO.File...) instead of just IO, but I haven't tried to run it.
Imports System.IO
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
SaveFileDialog1.FileName = ""
SaveFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"
SaveFileDialog1.ShowDialog()
If SaveFileDialog1.FileName.Trim.Length <> 0 Then
Dim fs As New FileStream(SaveFileDialog1.FileName.Trim, FileMode.Create)
Dim sr As New StreamWriter(fs)
sr.Write(TextBox1.Text)
fs.Flush()
sr.Close()
fs.Close()
End If
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
OpenFileDialog1.FileName = ""
OpenFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"
OpenFileDialog1.ShowDialog()
If OpenFileDialog1.FileName.Trim.Length <> 0 Then
Dim fs As New FileStream(OpenFileDialog1.FileName.Trim, FileMode.Open)
Dim sw As New StreamReader(fs)
TextBox1.Text = sw.ReadToEnd
fs.Flush()
sw.Close()
fs.Close()
End If
End Sub
End Class
this is a complete functional program if you want, you just need to drag drop a textbox, openfiledialog, and a savefiledialog.
feel free to play around with the code.
enjoy
by the way, the problem in your code is that you "must" close filestream when your done using it, doing so will release any resource such as sockets and file handles.
The .net framework is a very powerful framework. In the same way (however) it has easy and convenient methods for simple tasks. Most individuals tend to complicate things in order to display knowledge. But less code = less processing = faster and more efficient application (sometimes) so the large above method may not be suitable. Along with that, the above mentioned method would be better off written as a sub or if returning something then a function.
My.Computer.FileSystem.WriteAllText("File As String", "TextAsString", Append as Boolean)
A general Example would be
My.Computer.FileSystem.WriteAllText("C:\text.text", "this is what I would like to add", False)
this is what I would like to add
can be changed to the current text of a field as well.
so a more specific example would be
My.Computer.FileSystem.WriteAllText("C:\text.text", fullNameBox.text, True)
If you would like to understand the append part of the code
By setting append = true you are allowing your application to write the text at the end of file, leaving the rest of the text already in the file intact.
By setting append = false you will be removing and replacing all the text in the existing file with the new text
If you don't feel like writing that part of the code (though it is small) you could create a sub to handle it, however that method would be slightly different, just for etiquette. functionality would remain similar. (Using StreamWriter)
Private Sub WriteText()
Dim objWriter As New System.IO.StreamWriter("file.txt", append as boolean)
objWriter.WriteLine(textboxname.Text)
objWriter.Close()
End Sub
The Specific Example would be
Private Sub WriteText()
Dim objWriter As New System.IO.StreamWriter("file.txt", False)
objWriter.WriteLine(fullnamebox.Text)
objWriter.Close()
End Sub
then under the button_click event call:
writetext()
You can take this a step further as well. If you would like to create a more advabced Sub to handle any textbox and file.
Lets say you plan on having multiple separate files and multiple fields for each file (though there is a MUCH cleaner more elegant method) you could create a function. {i'll explain the concept behind the function as thoroughly as possible for this example}
below is a more advanced sub demonstration for your above request
Private Sub WriteText(Filename As String, app As Boolean, text As String)
Dim objWriter As New System.IO.StreamWriter(Filename, app)
objWriter.WriteLine(text)
objWriter.Close()
End Sub
What this does is allows us to (on the same form - if you need it global we can discuss that another time, it's not much more complex at all) call the function and input the information as needed.
Sub Use -> General Sample
WriteText(Filename As String, app As Boolean)
Sub Use -> Specific Sample
WriteText("C:\text.txt, False, fullnamebox.text)
But the best part about this method is you can change that to be anything as you need it.
Let's say you have Two Buttons* and **Two Boxes you can have the button_event for the first button trigger the above code and the second button trigger a different code.
Example
WriteText("C:\text2.txt, False, halfnamebox.text)
The best part about creating your own functions and subs are Control I won't get into it, because it will be off topic, but you could check to be sure the textbox has text first before writing the file. This will protect the files integrity.
Hope this helps!
Richard Sites.
The reason I ask is that I want to print, at run-time, a file in the application's resources, like this:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim printProcess As New Process
printProcess.StartInfo.CreateNoWindow = True
printProcess.StartInfo.FileName = "C:\Users\Geoffrey van Wyk\Documents\Countdown_Timer_Help.rtf"
printProcess.StartInfo.FileName = My.Resources.Countdown_Timer_Help
printProcess.StartInfo.Verb = "Print"
printProcess.Start()
End Sub
When I use "C:\Users\Geoffrey van Wyk\Documents\Countdown_Timer_Help.rtf" as the argument of FileName, it works. But when I use My.Resources.Countdown_Timer_Help, it says it cannot find the file.
No you didn't get it, that file will only be present on your dev machine. After you deploy your program, the file will be embedded in your program and cannot be printed. You'll have to write the code that saves the file from the resource to disk, then prints it. For example:
Private Sub btnPrint_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPrint.Click
Dim path As String = Application.UserAppDataPath
path = System.IO.Path.Combine(path, "Help.rtf")
System.IO.File.WriteAllText(path, My.Resources.Countdown_Timer_Help)
Dim printProcess As New Process
printProcess.StartInfo.CreateNoWindow = True
printProcess.StartInfo.FileName = path
printProcess.StartInfo.Verb = "Print"
printProcess.Start()
End Sub
Given that you have to save the resource to a file, it probably makes more sense to simply deploy the file with your app instead of embedding it as a resource and writing it to disk over and over again. Use Application.ExecutablePath to locate the file. To make that work at debug time you have to copy the file to bin\Debug. Do so by adding the file to your project with Project + Add Existing Item and setting the Copy to Output Directory property to Copy if Newer.
OK, I got it.
System.IO.Path.GetFullPath(Application.StartupPath & "\..\..\Resources\") & "Countdown_Timer_Help.rtf"