I'm currently talking to another computer to see what events they have occurring. I have setup a Wql Event query like so below:
Console.WriteLine("Polling...")
Try
Dim query As New WqlEventQuery("SELECT * FROM Lnl_AccessEvent")
Dim accessEventWatcher = New ManagementEventWatcher("SELECT * FROM Lnl_AccessEvent")
accessEventWatcher.Start()
accessEventWatcher.WaitForNextEvent()
Console.WriteLine("AccessEvent Occured.")
Catch ex As Exception
Console.WriteLine(ex.Message + " " + ex.StackTrace)
End Try
On the ".Start()" line, I get an exception stating "Invalid class" and "ManagementException". I know the connection is working since before this instance I'm able to connect and get the basic info from the remote computer's WMI, like IP address. The only solutions I have found is that has to do with my target build being only x86, but now it's at AnyCPU and still has this issue.
What is causing this error?
Related
Been breaking my head overnight with this. Couldn't get any help from earlier forums.
My app runs smoothly on other computers, it's been installed on five clients now with no problems. On this new machine, I keep getting the "Load Report Failed" when I open a report. It just leaves the CR Viewer blank afterwards.
UPDATE: I've checked the permissions, the app is able to make temporary files on the temp folder. But on my dev machine, it creates 2 files (the other file has curly brackets on it), on this particular client machine (where the error occurs), it only creates one.
I copy the bin folder content to client computers. The reports are set to Embedded Resource for Build Action and Do not Copy for Copy to Output Directory. This settings have run smoothly over the years with no problems on other client machines. I did not change anything in the report-retrieving code.
This is a sample code I've been using:
Try
Dim CR As New CRInventory
CR.SetDataSource(DataTable)
CR.SetParameterValue("GeneratedBy", ActiveStaffMember.Fullname)
CR.SetParameterValue("BusinessDetails", BusinessName & ", " & BusinessAddress)
CR.SetParameterValue("ReportDate", ReportDate)
CRV.ReportSource = CR
Catch ex As TypeInitializationException
ShowApplicationRuntimeErrorNotebox("LoadReport TypeInitializationException", ex.InnerException.Message)
Catch ex As Exception
ShowApplicationRuntimeErrorNotebox("LoadReport", ex.Message)
End Try
So what's new with this computer? I don't know, it has the latest Windows update I guess?
Any help will do, please. I'm this close to throwing this new computer out of the window.
UPDATE: Used ex.tostring instead of ex.Message to somehow catch the error (thanks Seb) and this went out:
CrystalDecisions.Shared.CrystalReportsException: Load report failed. ---> System.Runtime.InteropServices.COMException: The document has not been opened.
at CrystalDecisions.ReportAppServer.ClientDoc.ReportClientDocumentClass.get_ReportAppServer()
at CrystalDecisions.ReportAppServer.ReportClientDocumentWrapper.get_ReportAppServer()
at CrystalDecisions.ReportAppServer.ReportClientDocumentWrapper.EnsureDocumentIsOpened()
--- End of inner exception stack trace ---
at CrystalDecisions.ReportAppServer.ReportClientDocumentWrapper.EnsureDocumentIsOpened()
at CrystalDecisions.CrystalReports.Engine.ReportDocument.Load(String filename, OpenReportMethod openMethod, Int16 parentJob)
at CrystalDecisions.CrystalReports.Engine.ReportClass.Load(String reportName, OpenReportMethod openMethod, Int16 parentJob)
at CrystalDecisions.CrystalReports.Engine.ReportDocument.EnsureLoadReport()
at CrystalDecisions.CrystalReports.Engine.ReportDocument.SetDataSourceInternal(Object val, Type type)
at CrystalDecisions.CrystalReports.Engine.ReportDocument.SetDataSource(DataTable dataTable)
at Iceberg.FItemInventoryReportB.LoadReport() in D:\Documents\Iceberg\Iceberg VS2017\Iceberg\Forms\Items\Inventory\Inventory Transactions\FItemInventoryReportB.vb:line 38
UPDATE: Used procmon.exe to monitor the app's file system activity during report loading. All results are a SUCCESS. Unless I'm barking at the wrong tree.
I have developed a .Net application that I want to share to users through shared file in the LAN that is managed through a Domain server. When the server is up and running its fine but when the server is shut down an error comes. I have access to sql server database in that server. When server is shut down it gives a fatal error and application stops. How to detect the error of server being down?
I am connecting to the server through the following code:
Dim sql As String
Dim daCourseMaster As SqlDataAdapter
Try
sqlConn = New SqlConnection(connString)
sqlConn.Open()
sql = " ... "
daCourseMaster = New SqlDataAdapter(sql, sqlConn)
daCourseMaster.Fill(dsDataset, "table")
dvRegister = New DataView
dvRegister = dsDataset.Tables("courseRegisters").DefaultView
dgvCourseRegister.DataSource = dvRegister
Catch ex As Exception
MsgBox(Err.Description)
End Try
Now there might be different reasons why user can not login to the server: either the server name is wrong or user name or password is wrong or thebserver might be shut down! How to differentiate between these reasons to let the user know what might be the reason to failed login?
Use this code before the code that do the sharing (if the code in a Sub):
If Not My.Computer.Network.Ping(" You Server Name or Server IP") Then Exit Sub
or (if the code in a Function):
If Not My.Computer.Network.Ping(" You Server Name or Server IP") Then Exit Function
Lets say, you need to query your database. When you open connection and then when you execute your query, use Try-Catch Block and intercept SqlException. It has different codes, so you can test it for connectivity -related codes
Try
Using conn as new SqlConnection(...)
conn.Open()
....
End Using
Catch (connEx as SqlException)
' sql - related error handling
Catch (ex as Exception)
' here handle all other exception
End Try
this way, you can let user know that connection has lost and "try again later" or something like this
I seem to be receiving random error messages when trying to read queries from a SQLite DB stored on a network drive. On my development machine, I rarely ever get an error, but users are reporting random errors such as:
Unable to open database. File is encrypted or is not a database
Database disk image is malformed
Or it just doesn't return any data.
My code looks like such:
Private Sub LoadStoreCalls()
Dim tmpID As String
Dim QryString As String
Dim SQLconnect As New SQLite.SQLiteConnection()
SQLconnect.ConnectionString = "Data Source=" & SpiceWorksPath & ";New=False;Compress=True;Read Only=True;"
Try
'Open a connection to the database
SQLconnect.Open()
'Get StoreCode
tmpID = Mid(StoreCode, 2) & "-" & StoreName
QryString = "SELECT id, summary, status, c_location, c_store_device FROM tickets WHERE status = 'open' AND c_location = '" & tmpID & "'"
Dim ExQry As New SQLiteCommand(QryString, SQLconnect)
ExQry.CommandType = CommandType.Text
Dim da As New SQLiteDataAdapter(ExQry)
dasSpice.Clear()
da.Fill(dasSpice, "Calls")
SQLconnect.Close()
Catch ex As Exception
If SQLconnect.State = ConnectionState.Open Then SQLconnect.Close()
MsgBox(ex.Message)
End Try
End Sub
The problem is that my application relies on this data being returned to populate additional entries of a datagridview control, and because I cannot replicate this error on my development machine using debug, I cannot find where the fault is occurring.
If the user gets one of these errors, they usually keep trying to run the query and eventually it will work. Or they just exit my application and go back in and then it seems to work for a while. The errors are random and not always from running the same query.
I'm assuming it's due to an issue talking to an SQLite DB on a shared drive, but I can't find any information regarding setting timeouts. I also can't work out how to 'catch' the error because I can't replicate it myself. I have tried adding logging details to the Catch event handler, but it simply just returns me the error message (above) in the logs.
Any help would be greatly appreciated.
Thanks
After many hours of troubleshooting and researching I found that SQLite does not play well with remote connections. Not only was it causing errors in my application, it was also throwing errors in the parent application.
My alternative was to write an application to query the database that ran locally on the SQLite machine. This fixed all of my issues.
For anyone interested...
I'm writing a windows service which runs as the local system account. I'm trying to make sure if I have full read/write access to a file beginning to process it any further. Here is my code:
Dim FullPath As String
FullPath = "C:\directory\file.txt"
Dim ps As Security.PermissionSet
ps = New Security.PermissionSet(Security.Permissions.PermissionState.Unrestricted)
ps.AddPermission(New Security.Permissions.FileIOPermission(Security.Permissions.FileIOPermissionAccess.AllAccess, FullPath))
ps.AddPermission(New Security.Permissions.FileIOPermission(Security.Permissions.FileIOPermissionAccess.AllAccess, IO.Path.GetDirectoryName(FullPath)))
Try
ps.Demand()
Catch ex As Security.SecurityException
System.Diagnostics.EventLog.WriteEntry("ShopLink", "File " + FullPath + " will not be parsed. " + ex.Message)
Exit Sub
Catch ex As Exception
System.Diagnostics.EventLog.WriteEntry("ShopLink", "File " + FullPath + " will not be parsed. " + ex.Message)
Exit Sub
End Try
Then I set the full access permissions for the file to "Deny" for the user account my service is running as. After executing, the code above doesn't throw any exceptions and allows file processing to begin. When the service later tries to change and/or delete the file, I get an "Access Denied" exception.
Any suggestions?
For this purpose i use thise small function:
Private Function HasAccess(ByVal ltFullPath As String)
Try
Using inputstreamreader As New StreamReader(ltFullPath)
inputstreamreader.Close()
End Using
Using inputStream As FileStream = File.Open(ltFullPath, FileMode.Open, FileAccess.ReadWrite, FileShare.None)
inputStream.Close()
Return True
End Using
Catch ex As Exception
Return False
End Try
End Function
In your case then:
If HasAccess(FullPath) ...
I have solved the problem by using My.Computer.FileSystem.DeleteFile to delete the file instead of Kill. My.Computer.FileSystem.DeleteFile was executed without problems after successfully demanding full read/write access to the file in the way described above, while Kill consistently threw an "Access denied" exception.
Using "Kill"... I know this is a very old thread but I'll add this in case anyone stumbles on it like I did. I was working on some old VB6 legacy code. One of my clients users was getting a runtime exception during a file open after a kill. The code was "Killing" the file and then rebuilding it from scratch with binary data held in memory. It tuns out that the "Kill" function triggered the user's anti-virus software which locked the file long enough to cause the next "Open" statement to fail. I discovered this using an error logging utility (the name escapes me at the moment). The line in the error log file on the failed "Open" statement was that the file's status was "Delete pending" due to the user's anti-virus software.
I'm working on creating a windows service that will send emails to a customer when they are within a month of having their submission expire. I'm using vb.net in Visual Studios 2008
Because it's a windows service it's very difficult to debug. Trying to narrow down my error I created a "sendDebugEmail" method that sends me an email if it gets to a certain line. The emails never make it past "dr = cmd.ExecuteReader()"
I'm wondering what I am doing wrong. My SQL statement should work fine. I've tested it in my SQL server database.
I've created a dummy_database that I just made in sql server as well. I added an INSERT sql statement for the dummy table i have in there just to see if i could actually access a database. All the table takes in is the line number and time it was sent. When I run my windows service that database updates just fine.
Any help would be appreciated. Thanks
Dim conn As New SqlConnection(connString2)
sendDebugEmail("134")
SQL = "Select email FROM _Customer WHERE custID in (SELECT custID FROM _OnlineCustomer WHERE ExpirationDate <= '6-20-12' AND ExpirationDate >= '6-10-12')"
Dim cmd As New SqlCommand(SQL, conn)
sSubject = "hello"
sBody = "This is test data"
Dim dr As SqlDataReader
sendDebugEmail("143")
Try
dr = cmd.ExecuteReader() // This is were it stops
sendDebugEmail("147")
While dr.Read
sendDebugEmail("152")
Try
LogInfo("Service woke up")
Dim i As Integer = 0
' Prepare e-mail fields
sFrom = "test#gmail.com"
sTo = "test1#gmail.com"
sCc = "test2#gmail.com"
Dim oMailMsg As MailMessage = New MailMessage
oMailMsg.From = sFrom
oMailMsg.To = sTo
oMailMsg.Cc = sCc
' Call a stored procedure to process the current item
' The success message
oMailMsg.Subject = sSubject + "(Success)"
oMailMsg.Body = sBody + "Email has been sent successfully."
' Send the message
If Not (oMailMsg.To = String.Empty) Then
SmtpMail.Send(oMailMsg)
End If
Catch obug As Exception
LogEvent(obug.Message)
Finally
End Try
End While
Catch ex As Exception
Finally
dr.Close()
cmd.Dispose()
conn.Close()
conn.Dispose()
End Try
End Sub
/////////////////////////////////////////////////////////////////////////////////
Problem Solved: I set up my connection but I never opened it.
I needed conn.open()
The thing that helped me most was adding this code into my last catch statement:
sendDebugEmail(ex.Message & vbcrlf & ex.stackTrace)
It send me an email of the stackTrace and made it very easy to debug
Are you trapping and swallowing exceptions? If you are, stop. Let exceptions service crash the service: the exception will be logged in the Event log. The only exceptions you should trap are those you can actually recover from (though its valid to catch the exception, log it and rethrow it via throw;).
Have you instrumented your code with log4net (http://logging.apache.org/log4net/), or something similar? You should be, especially for a daemon like a Windows service — how else are you (or operations) going to diagnose problems with the service when the occur (as they will).
Edited to note:
You should be using using statements: all those ADO.Net objects are IDisposable. It makes for cleaner code.
Consider using a SqlDataAdapter to fill a DataTable or DataSet with your results set. The pattern you're using:
read a row from SQL
while read was successful
send an email
read a row from SQL
will ultimately lead to blocking in your database. Talking to a mail server has the potential for a high latency. If the mail server doesn't answer, or you have network congestion, or any of a number of other reasons, you're going to be left hanging until the mail is sent or an exception is thrown due to timeout. And your SQL Query is going to be sitting there with read locks on the table and indices from which you're reading data, blocking people attempting to do updates, inserts or deletes. Your production DBAs will be...vexed. You want to keep your locks moving and get the locks released as quick as you can.
If you are sure about your code (with no exceptions) i think you should check the authentication you are using to connect the SQL server(inside the connection string within the app.config file/inline code of the windows service).
If you are using SQL authentication for this (check the connection string for user name sa and its password) setting the account type of the windows service to LocalService will help you.
If the SQL connection is using windows authentication then setting the account type of the windows service to LocalSystem will help you.
The Account type modification can be done after installation also. For this go to Control panel->Administrative tools->Services->YourService right click and select Propertes->Logon and perform it there. If you are selecting the LocalSystem (windows authentication) you will be asked to enter the login credentials of the account in which the service is running.
In the case of windows authentication in SQL connection the credentials of the account in which the service is running will be taken for SQL connectivity also.
Hope this helps ...
One more suggestion put a sleep statement on your process when it starts so oyu have time to attach to it
Problem Solved: I set up my connection but I never opened it.
I needed conn.open()
The thing that helped me most was adding this code into my last catch statement:
sendDebugEmail(ex.Message & vbcrlf & ex.stackTrace)
It send me an email of the stackTrace and made it very easy to debug