I have created a VS application , I have installed a copy on another computer and I wish to link them via LAN so that if settings are canged in one , the others setings will also be saved .
for example this setting
i created a new name in the sttings are and call it "AdminIn" and set its type it integer , its scope to user and set its value to 0
Dim AI As New My .MySettings
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
AI.AdminIn = AI.AdminIn + 1
Ai.SAve()
End Sub
now how can AI also be updated in the other application on the other computer .
How do I connect via LAN and accomplish this ?
I found this link that provides some example code to modify application-scoped variables from My.Settings that might be useful. I've tested it out with a simple form with a timer and a label showing me the current value of the AdminIn setting, and it seems to work. The timer updates the label on every instance of the form by checking the reloaded My.Settings value. The variable would need to be application scoped in order to be accessible to all users on any machine that may run the executable.
http://www.codeproject.com/Articles/19211/Changing-application-scoped-settings-at-run-time
Here's the form code that I put together to keep the current admin count up-to-date. Very simplistic, but it seems to do the job neatly.
Public Class Form1
Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
'Decrement the AdminIn count when the current instance of the form is closed.
Me.tmrAdminCheck.Stop()
ChangeMyAppScopedSetting((My.Settings.AdminIn - 1).ToString)
'Reload the .exe.config file to synchronize the current AdminIn count.
My.Settings.Reload()
My.Settings.Save()
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Increment the current AdminIn count when a new instance of the form is loaded
ChangeMyAppScopedSetting((My.Settings.AdminIn + 1).ToString)
'Reload the .exe.config file to synchronize the current AdminIn count.
My.Settings.Reload()
My.Settings.Save()
Me.lblAdminsIn.Text = "Current Admins In: " & My.Settings.AdminIn.ToString
'Start the timer to periodically check the AdminIn count from My.Settings
Me.tmrAdminCheck.Enabled = True
Me.tmrAdminCheck.Interval = 100
Me.tmrAdminCheck.Start()
Me.Refresh()
Application.DoEvents()
End Sub
Private Sub tmrAdminCheck_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrAdminCheck.Tick
'Reload the .exe.config file to synchronize the current AdminIn count.
My.Settings.Reload()
Me.lblAdminsIn.Text = "Current Admins In: " & My.Settings.AdminIn.ToString
Me.Refresh()
Application.DoEvents()
End Sub
End Class
I've found a couple of things with this method, and they relate to what others have already mentioned in their comments:
The application's .exe.config file must be in an accessible location (the CodeProject example defaults to the application's executable directory). Of course, you could save the settings to an INI file or some other configuration file in another shared directory and accomplish a similar thing, but this method uses the My.Settings.
You'll may want to do some additional checking for the possibility
of two people attempting to get in at exactly the same time. If
that happens, the configuration file will still be open and locked,
and the new AdminIn value won't be saved. The CodeProject example
doesn't have any exception handling, but you could easily work this
functionality into the exception handling by making a recursive call
to the Sub.
Otherwise, this seems to be a totally viable method of accomplishing what you're talking about.
Related
I wanted to create an application with two forms, a main one called Source and a subsidiary called Viewer. Using buttons on each form, the user could switch to the other, even if that form had previously been closed. So I set my program to Close When Last Form Closes. Moreover, I added message boxes when each form closed, just to check that the user was sure.
But now my application won't exit after I close both forms! It shows up in Task Manager, and if I run it in MSVS, the debugger never stops! When each form is closed, My.Application.Forms returns an empty collection. And if I force quit it using End/Application.Exit, the program still quits — see the MWE below. What do I do?
MWE
Create a blank VB.NET Windows Forms project. In the "Application" tab of your project's settings, choose "Close When Last Form Closes." In the designer, create a Form Source with one button.
Public Class Source
Public Sub Switch(sender As Object, e As EventArgs) Handles Button1.Click
My.Forms.Viewer.Show()
End Sub
Public Sub Free(sender As Object, e As FormClosingEventArgs) Handles Me.Closing
e.Cancel=(MsgBoxResult.Cancel=MsgBox("Are you sure?"))
End Sub
'Public Sub Test(sender As Object, e As EventArgs) Handles Me.Closed
'Debug.Assert(Not My.Application.Forms.Count))
'If the next line is uncommented, the application will close, like we want
'If Not My.Forms.Viewer.Visible Then Application.Exit()
'End Sub
End Class
Then create an identical form called Viewer.
Public Class Viewer
Public Sub Switch(sender As Object, e As EventArgs) Handles Button1.Click
My.Forms.Source.Show()
End Sub
Public Sub Free(sender As Object, e As FormClosingEventArgs) Handles Me.Closing
e.Cancel=(MsgBoxResult.Cancel=MsgBox("Are you sure?"))
End Sub
'Public Sub Test(sender As Object, e As EventArgs) Handles Me.Closed
'Debug.Assert(Not My.Application.Forms.Count))
'If the next line is uncommented, the application will close, like we want
'If Not My.Forms.Source.Visible Then Application.Exit()
'End Sub
End Class
Try closing any form last. Neither will cause the app to quit.
Don't use Form.Closing and Form.Closed
In MSDN's page on Form.Closing, it remarks:
Caution
The Closing event is obsolete in the .NET Framework version 2.0 [and above]; use the FormClosing event instead.
The events were deprecated because
The Form.Closed and Form.Closing events are not raised when the Application.Exit method is called to exit your application. If you have validation code in either of these events that must be executed, you should call the Form.Close method for each open form individually before calling the Exit method.
The MSDN documentation nowhere states this, but the reverse is true: in order for your form to signal to the VB.NET runtime that the form closed, Form.Closing and Form.Closed cannot be subscribed to.
If you replace Me.Closing with Me.FormClosing and Me.Closed with Me.FormClosed in your MWE, it works.
how can i make my application goes to function after certain usage
like if i click an button 10 times, then button is disabled
just like trial program,
so far, i can do that on run-time only,
how can i make it count clicks without using Registry?
my program is very simple: convert strings to Base64
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Text = Convert.ToBase64String(New System.Text.ASCIIEncoding().GetBytes(TextBox1.Text))
End Sub
You probably need Settings. Easily Save and Retrieve Application and User Settings in VB.NET or C# Apps. First create ClickCouter of type integer with value 0 in settings (see the article).
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
My.Settings.ClickCouter +=1
My.Settings.Save()
If My.Settings.ClickCouter>=10 then Button1.Enabled = False
End Sub
It is necessary to check ClickCouter also in Form_Load. The value is stored in a file in a user profile so the solution is not too "hacker proof" (but is fool proof :-D ).
Is there any way I can save changes made by a user , so that at the next run they would still be there? I have seen something about My.Settings , is that how it is done?
Yes you have multiple options, you can create a file and load it on startup, or you can use the built in settings object. Just go to your Project Property's --> settings set your variable there, the you can access it through My.Settings
Then load it like this:
Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
Dim greeting As String = My.Settings.mySetting
End Sub
you would change the value and save it like this
My.Settings.mySetting = "GoodBye"
My.Settings.Save()
I'm trying to create an app launcher in vb.net but I do not know how to save files. Save files like the one that is executed when you run a setup for an application wherein the setup will save the application files on program files folder. I'm not trying to create a vb.net setup, because I want to run my program as portable. What I want the program to do is to place the files in their appropriate location when the user clicks a button
Here's my current code:
Public Class Nircmd
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'shutdown
System.Diagnostics.Process.Start("E:\Documents and Settings\Rew\Desktop\Shutdown.lnk")
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
'monitor off
System.Diagnostics.Process.Start("E:\Documents and Settings\Rew\Desktop\Monitor Off.lnk")
End Sub
End Class
-Of course it won't work if the path doesn't contain the file specified. So I want to place another button that would do just that(to save the files specified in the desired folder.
A simple syntax will do. Please
I don't quite understand, but I'll take a shot.
This will check to see if C:\foo\somefile.txt exists, and if it doesn't, create it and write some text:
If Not System.IO.File.Exists("C:\foo\somefile.txt") = True Then
Dim file As System.IO.FileStream
file = System.IO.File.Create("C:\foo\somefile.txt")
file.Close()
End If
My.Computer.FileSystem.WriteAllText("C:\foo\somefile.txt", "Some text")
If you want to copy or move a file, I think you'll want something like:
System.IO.File.Copy("C:\foo\somefile.txt", "C:\bar\somefile.txt")
or
System.IO.File.Move("C:\foo\somefile.txt", "C:\bar\somefile.txt")
I always use app.path in order to make it portable. Not everyone's computer will assign the same drive letter.
My application periodically starts console programs with process.start. I need to monitor the output of the programs in "realtime".
For example, the program writes the following text to the console:
Processing.................
Every second or so a new dot appears to let the user know the program is still processing. However,... until the programm outputs a CR/LF, I am not able to retrieve the standard output of the program (while it is still running).
What can I do to get the output in realtime for - let's say - piping it into a database for instance in VB.NET?
what about sending output into a text file and reading that file every second?
I'm gutted since I did have a prototype application at home that did something like this. I'll see if I can fetch it. In the meantime have a look at this link:
http://msdn.microsoft.com/en-us/library/system.diagnostics.process.standardoutput.aspx
It shows how to redirect the output of applications to a custom stream e.g.
Public Class Form1
Private _p As Process
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim psi As New ProcessStartInfo()
psi.FileName = "C:\mydir.bat"
psi.RedirectStandardOutput = True
psi.UseShellExecute = False
_p = New Process()
_p.Start(psi)
tmrReadConsole.Enabled = True
End Sub
Private Sub tmrReadConsole_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrReadConsole.Tick
If _p IsNot Nothing Then
txtConsoleOutput.Text = _p.StandardOutput.ReadToEnd()
End If
End Sub
End Class
The above is a webform that has a timer which is used to poll the output stream of a console and get it's content into a textbox. It doesn't quite work (hence why I want to find my other app), but you get the idea.
Hope this helps.