I am studying VB.NET and looking for way to check if application mapped to network drive.
I check
vb.net how to check if a network drive is mapped persistently
and i also trying to ping to network drive. However, this method seem not workinng.
I was trying ping to network drive and it was always return false.
I made function.
On the function part
Public Function CheckForInternetConnection(path As String) As Boolean
Try
Using client = New WebClient()
Using stream = client.OpenRead(path)
Return True
End Using
End Using
Catch
Return False
End Try
End Function
On the running part i call this function above
CheckForInternetConnection("google.com")
CheckForInternetConnection("\\mynetowrk_Driver.com\system\application")
When i use CheckForInternetConnection with "google.com" it return "TRUE"
However, when i use "\mynetowrk_Driver.com\system\application" this network drive, it return FALSE
I am not sure how i can check if netowork driver was mapped .
If I understand correctly, you are trying to validate two different things. See if the code below helps you:
Public Function CheckForInternetConnection(path As String) As Boolean
Try
Return My.Computer.Network.Ping(path)
Catch pingException As System.Net.NetworkInformation.PingException
Return IO.Directory.Exists(path)
Catch ex As Exception
Return False
End Try
End Function
Related
I have a WCF Netnamedpipebinding from my application to an Office Addin. I have noticed that when the office app is busy doing something else that my application locks up when using a WCF method. I have added an example of my code. It appears that the code stops and waits with the channel.close method.
Is the solution to change channel.close to channel.BeginClose ?
What is the the state object I need to pass in to the BeginClose method?
Public Function RequestPersonStatus(ByVal id As String, ByVal email As String)
Using factory As New ChannelFactory(Of IToOffice)(New NetNamedPipeBinding(), New EndpointAddress("net.pipe://localhost/" + XXXXXX))
Dim OfficeChannel As IToOffice = factory.CreateChannel()
Try
OfficeChannel.RequestPersonStatus(id:=id, email:=email)
Catch ex As Exception
Return False
Finally
CloseChannel(CType(OfficeChannel, ICommunicationObject))
End Try
End Using
Return True
End Function
and the closeChannel
Private Sub CloseChannel(ByVal channel As ICommunicationObject)
Try
If channel.State = CommunicationState.Opened Then
Dim caller As New AsyncCallback(AddressOf callback)
channel.BeginClose(caller, New Object)
' channel.Close()
End If
Catch ex As Exception
Log(LogTypes.AllExceptions, "CloseChannel - Error closing the channel. ", ex.ToString)
Finally
channel.Abort()
End Try
End Sub
There seems to be a lot of discussion on what and when to clean up / Dispose / close down channels. I am just posting here what I am now doing and thus my answer to my question.
Private Sub CloseChannel(ByVal channel As ICommunicationObject)
Try
If channel.State <> CommunicationState.Closed AndAlso channel.State <> CommunicationState.Faulted Then
channel.BeginClose(Sub(asr)
Try
channel.EndClose(asr)
Catch
channel.Abort()
End Try
End Sub, Nothing)
Else
channel.Abort()
End If
Catch commEx As CommunicationException
channel.Abort()
Catch ex As Exception
channel.Abort()
Finally
End Try
End Sub
As far as I know, most of the cases like the timeout error/connection/communication error are caused by that the channel/client proxy is not properly closed. Putting the client proxy/Service Channel in a using block will eliminate the problem.
using (ServiceReference1.ServiceClient client=new ServiceClient())
{
var result = client.Test();
Console.WriteLine(result);
}
The Using statement is useful for automatically closed the service proxy/service communication channel after completing the invocation. Besides, Service client proxy is similar to the communication channel created by the ChannelFactory.
Feel free to let me know if there is anything I can help with.
I have a system that backs up data to a network with certain parameters in place such as:
'If x process is running, do not run the backup'
Because it's connected to a network, users will constantly be on it. The problem I have is that I don't want the data to get moved onto the network if it's in use, plus, the data is unable to move across if someone is using file explorer on the same computer as the program is on.
I would use 'If explorer is running, do not run the backup' but explorer is linked to windows and is always running
If program.Count > 0 Or program2.Count > 0 Then
Try
Msgbox("Process Running")
Catch ex As Exception
End Try
Else
'backup data
End If
Is there a way to try get the program to transfer files, but if fails because the file directory is already open, then do x?
Try this. It should generate an error if you can't lock the file.
Public Function IsFileLocked(file As FileInfo) As Boolean
Dim stream = DirectCast(Nothing, FileStream)
Try
stream = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None)
Catch generatedExceptionName As IOException
'handle the exception your way
Return True
Finally
If stream IsNot Nothing Then
stream.Close()
End If
End Try
Return False
End Function
I am currently working on a console application to play a freshly created WAV RIFF file, and then delete it. Like I said, it is freshly created, so I need to make sure the file isn't being edited before I start playing it or it will be corrupted. After it plays, I delete it.
Currently, my code looks like this (using System.IO):
Sub Main()
Dim fileName As String
fileName = "C:\temp\Burst\Burst.wav"
While CheckFile(fileName)
End While
Try
My.Computer.Audio.Play(fileName, AudioPlayMode.WaitToComplete)
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
My.Computer.FileSystem.DeleteFile(fileName)
End Sub
Private Function CheckFile(ByVal filename As String) As Boolean
Try
System.IO.File.Open(filename, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.None)
FileClose(1)
Return False
Catch ex As Exception
Return True
End Try
End Function
The function I am using to check if the file is opened was created by sealz. I found it here. Unfortunately, however, this function is causing an exception in that after it runs, the program cannot access the file because it is being used by another process. If I remove this function, the file can be opened, played and deleted.
The exception reads as follows:
An unhandled exception of type'System.IO.IOException' occurred in mscorlib.dll Additionalinformation: The process cannot access the file 'C:\temp\Burst\burst.wav' because it is being used by another process.
So the function that is supposed to help determine if the file is being used, is actually causing the file to be opened. It seems like it isn't closing. Is there anyway I can modify this current function to work properly for my application or are there any other ideas on how to tackle this. Thanks for your time.
-Josh
Here is your problem:
System.IO.File.Open(filename, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.None)
FileClose(1)
Return False
A Using will help:
Using _fs as System.Io.FileStream = System.IO.File.Open(filename, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.None)
End Using
Return False
File.Open Returns a Filestream, not an Integer needed for FileClose
As far as I get you are trying to check if file exists before playback using System.IO.File.Open however you may do it with File.Exists.
Method File.Exists from System.IO returns true if file exists on path and returns false the otherwise.
Also you are doing it wrong here,
While CheckFile(fileName)
End While
If file is found it will enter into an infinite loop without doing anything other than calling CheckFile repeatedly. If file is not found, it will get out of loop and attempt Audio.Play and FileSystem.DeleteFile and you end up getting a file not found exception.
Here is your code modified and working.
Imports System.IO
Module Module1
Sub Main()
Dim fileName As String
fileName = "C:\temp\Burst\Burst.wav"
While CheckFile(fileName)
Try
My.Computer.Audio.Play(fileName, AudioPlayMode.WaitToComplete)
'Delete statement here if you want file to be deleted after playback
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
End While
My.Computer.FileSystem.DeleteFile(fileName)
Console.ReadLine()
End Sub
Private Function CheckFile(ByVal filename As String) As Boolean
If (File.Exists(filename)) Then
Return True
Else
Return False
End If
End Function
End Module
Is there a method to verify that a file is open? The only thing I can think of is the Try/Catch to see if i can catch the file-open exception but I figured that a method be available to return true/false if file is open.
Currently using System.IO and the following code under class named Wallet.
Private holdPath As String = "defaultLog.txt"
Private _file As New FileStream(holdPath, FileMode.OpenOrCreate, FileAccess.ReadWrite)
Private file As New StreamWriter(_file)
Public Function Check(ByVal CheckNumber As Integer, ByVal CheckAmount As Decimal) As Decimal
Try
file.WriteLine("testing")
file.Close()
Catch e As IOException
'Note sure if this is the proper way.
End Try
Return 0D
End Function
Any pointers will be appreciated! Thank you!!
Private Sub IsFileOpen(ByVal file As FileInfo)
Dim stream As FileStream = Nothing
Try
stream = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None)
stream.Close()
Catch ex As Exception
If TypeOf ex Is IOException AndAlso IsFileLocked(ex) Then
' do something here, either close the file if you have a handle, show a msgbox, retry or as a last resort terminate the process - which could cause corruption and lose data
End If
End Try
End Sub
Private Shared Function IsFileLocked(exception As Exception) As Boolean
Dim errorCode As Integer = Marshal.GetHRForException(exception) And ((1 << 16) - 1)
Return errorCode = 32 OrElse errorCode = 33
End Function
Call it like this:
Call IsFileOpen(new FileInfo(filePath))
There is really no point using a 'is file in use check' function since you will still need to have try catch to handle the case that the file fails to open. The file open can fail for many more reasons than it just being already open.
Also using a function to do a check is no guarantee of success. The 'is file in use check' might return false only for the file open to fail with a file already open error, because in time between the check and trying to open the file it was opened by someone else.
It looks like the two suggestions from this MSDN forum posting both involve trying to open the file.
The first one is similar to what you are doing now, and the second involves using a Windows API function (CreateFile) and checking for a invalid handle signifying the file is in use. In both cases they are relying on an error condition to determine if the file is open or not. In short, in my opinion the method you are using is correct since there is not a System.IO.File.IsOpen property.
I need my application to check for internet connectivity on my user's computer. If there is, an image is displayed and if there isn't, a different image is displayed. Here's the code I used to get this to work:
Private Sub Window_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
If NetworkInformation.NetworkInterface.GetIsNetworkAvailable Then
Dim bi1 As New BitmapImage
bi1.BeginInit()
bi1.UriSource = New Uri("Images\greenbar.png", UriKind.Relative)
bi1.EndInit()
Image2.Source = bi1
Else
Dim bi2 As New BitmapImage
bi2.BeginInit()
bi2.UriSource = New Uri("Images\redbar.png", UriKind.Relative)
bi2.EndInit()
Image2.Source = bi2
MessageBox.Show("INTERNET CONNECTION NOT DETECTED")
MessageBox.Show("You must be connected to the internet to use some aspects of this application.")
MessageBox.Show("Please re-establish connection to the Internet and try again, thank you.")
Me.Close()
End If
End Sub
I decided to test this on my own computer by changing my default gateway (thereby making it seem as if I lost connection). But I realized that the code still showed that I was connected. So I'm thinking that it's only checking for connectivity of the interface - which in this case, is my connection to the router (which is true, I was connected to the router).
So, the question: How do I check that the user's PC is actually connected to the internet? I read the article What is the best way to check for Internet connectivity using .NET? but it's in C# and I don't understand that.
You can use this tool to translate C# to VB.NET or vice-versa:
Public Shared Function CheckForInternetConnection() As Boolean
Try
Using client = New WebClient()
Using stream = client.OpenRead("http://www.google.com")
Return True
End Using
End Using
Catch
Return False
End Try
End Function
By the way, the NetworkInterface.GetIsNetworkAvailable method you've used checks whether any network connection is available or not - not Internet Connectivity.
A network connection is considered to be available if any network
interface is marked "up" and is not a loopback or tunnel interface.
Or use this code
If My.Computer.Network.IsAvailable Then
MsgBox("Computer is connected.")
Else
MsgBox("Computer is not connected.")
End If
If My.Computer.Network.Ping("www.Google.com") Then
...
End If
You could use this, which should help you out for VB & C# versions:
Public Function IsConnectionAvailable() As Boolean
' Returns True if connection is available
' Replace www.yoursite.com with a site that
' is guaranteed to be online - perhaps your
' corporate site, or microsoft.com
Dim objUrl As New System.Uri("http://www.google.com/")
' Setup WebRequest
Dim objWebReq As System.Net.WebRequest
objWebReq = System.Net.WebRequest.Create(objUrl)
objWebReq.Proxy = Nothing
Dim objResp As System.Net.WebResponse
Try
' Attempt to get response and return True
objResp = objWebReq.GetResponse
objResp.Close()
objWebReq = Nothing
Return True
Catch ex As Exception
' Error, exit and return False
objResp.Close()
objWebReq = Nothing
Return False
End Try
End Function
Public Function IsConnectionAvailable() As Boolean
' Returns True if connection is available
' Replace www.yoursite.com with a site that
' is guaranteed to be online - perhaps your
' corporate site, or microsoft.com
Dim objUrl As New System.Uri("http://www.yoursite.com/")
' Setup WebRequest
Dim objWebReq As System.Net.WebRequest
objWebReq = System.Net.WebRequest.Create(objUrl)
Dim objResp As System.Net.WebResponse
Try
' Attempt to get response and return True
objResp = objWebReq.GetResponse
objResp.Close()
objWebReq = Nothing
Return True
Catch ex As Exception
' Error, exit and return False
objResp.Close()
objWebReq = Nothing
Return False
End Try
'Here’s how you might use this function in your application:
If IsConnectionAvailable() = True Then
MessageBox.Show("You are online!")
End If
The following will check network connection availability and Internet connection both :
If My.Computer.Network.IsAvailable Then
Try
If My.Computer.Network.Ping("www.Google.com") Then
Infolabel.Text = "Computer is connected to the internet"
Else
Infolabel.Text = "Computer is not connected to the internet"
End If
Catch
End Try
Else
Infolabel.Text = "Computer is not connected to the internet"
End If