What Happens If The Callback Method Takes More Than The Specified Timer's Time Period
Mar 1, 2011
I have the below code. What happens if the Upload method takes more than one minute for completion? Does the timer kick off another call to the Upload method immediately after one minute is over or Does it wait until the method finishes executing? I am implementing this as a windows service.
Protected Overrides Sub OnStart(ByVal args() As String)
Dim tmr As Timer = New Timer(New TimerCallback(AddressOf Upload), Nothing, 1000, 60000)
While Not tmr Is Nothing
Out of curiosity, is there a way i can make a program stop or pause for a period of time (which i would choose) before continuing the code WITHOUT a timer.I think I've seen this done before, but I'm not positive.Also note that I'm talking about a forms application (not a console app if that would be any different.)
I have an issue with a third-party COM+ DLL meant to be used from VB6, where it has a function to set a Callback for a hardware event. However, I'm using VB.NET, and AddressOf now returns a reference type instead of an integral type, which means that the setCallback function on the COM+ DLL apparently can't be used.
I was trying to use the System.Threading.Timer to run a function every 250ms - but I'm finding it difficult to cancel the timer from within the callback function. I can't seem to find a reference to "this" (js has this - it's so nice). At any rate - how could I start a callback running 250ms from now - without a timer - and then if I want to continue it again do another start for 250ms.
Quick question - if I have a timer set to 5000 (5 seconds) and the code in the timer takes longer than 5 seconds to run because of sql stuff, will the timer wait until the code is done till it fires again?
I create a UserControl (TableWithFilter.xaml) with a dependency property (source). The UserControl is a Table with a source property for the different items. I created the XAML and set the source property via the XAML Binding. So far so good.
But if the value of the dependency property is changed, the defined callback method is not called. Therefore I cannot update the entries in my table. Has anyone an idea why the callback method is not called?
Here is the definition of my property in the class "TableWithFilter":
Public Shared ReadOnly SourceProperty As DependencyProperty = _ DependencyProperty.Register("Source", GetType(List(Of TableViewItem)), GetType(TableWithFilter), _
[Code]....
If the attribute "ContentList" is changed I expet that the "ChangeSource" method in the TableWithFilder class is called. But this is not the case. After I changed the ContentList attribute, I Raise the following Event:
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("ContentList"))
I have a windows form that gets data from a scale via the serial port. Since I need the operator to be able to cancel the process I do the get data process on a second thread. The data collection process gets multiple readings from the scale one at a time. The form has a label that needs to be updated with information specific to each reading.
I call the method to get the data from the scale with this code. Dim ad As New readALine(AddressOf thisScale.readALine) Dim ac As New AsyncCallback(AddressOf Me.GetDataCallback) Dim iar As IAsyncResult = ad.BeginInvoke("", ac, ad)
The delegate for the readALine method is defined in the UI code. Delegate Function readALine(ByVal toSend As String) As String
The GetDataCallback method: Private Sub GetDataCallback(ByVal ia As IAsyncResult) . . . lblInstructions.Text = _thisMeasure.dt.Rows(_currRow - 1).Item("cnt") & ":" lblInstructions.Refresh() . . . End Sub
I get the exception on the "lblInstructions.Text =" statement. I thought the GetDataCallback method was part of the UI thread so don't understand why I'm getting the exception. I know this could probably be rewritten using a BackgroundWorker and it's appropriate events but for now would like to understand why this isn't working as expected. The application was written originally in VS2003 and just recently upgraded to VS2008.
I do not know Why I am recieving a TimeOutException in my code:
Dim Uri2 As New Uri("http://localhost:8733/Design_Time_Addresses/ssWcfService/Service1/") Dim binding2 As New WSDualHttpBinding() Dim callback = New MyCallBackClient()
I am an absolute beginner on ASP.net (VB.) Please pardon me if the question is too obvious for the experienced members.I tried to make a simple WebRequest in the async mode in case the target URL takes long to provide the data. In my code below, I just want to see if the callback block (RespCallback) is called correctly every time. If all goes well, lblResult should have the string '123' appended to it every time I click the button which calls the 'GetData' sub.
However, the lblResult only shows 123 after the first click. After the subsequent click, the lblResult only gets appended with '12', as if RespCallback is never called. When I tried to debug this in Visual Studio, the execution actually stepped right into the RespCallback part and the lblResult.Text watch actually shows '123123' but the resulting Web page always shows only '12312'
I am sure I am missing something basic here, but I just don't know what. I was even guessing that it has to do with browser cache (hence the result changes for the second time) but I don't know how to fix that either.
I am trying to display a dialog for a period of time. if the user is not present, I want it to close and perform a task. I am using a background worker, which is supposed to simulate a button click. It performs the button click fine, but the dialog never goes away.
Private Sub Backgroundworker_ProgressChanged() Handles BackgroundWorker1.ProgressChanged If Me.BackgroundWorker1.WorkerReportsProgress >= 100 Then
take a shot from a camera every last day of the month at midnight. I know how to to take the shot, but I don't know how to generate an event repetitively after a time period. I thought about to calculate the time between now and the next shot time, but how to run a method after a time period?
How can I loop through each date in a given time period so that I can add those dates as a column name in a table. I want to create datatable with the person's name and hours he worked in a given time period. The user will select the dates and I want to show each day/date in that table as a column name.
I have set up a simple quiz where you drop answers to the correct question. I have implemented a system where the are 18 text boxes (9 for questions, 9 for answers) and it can be customised but I want the questions to be able to be 'saved's since it in another form the if I give them special names when I close the form and open it again it has lost the values. Is there a way to remember the variables for a set period of time (cookies?) or if not just for that session?
Is there a way to code, so that if your program freezes over a period of time (5sec), it just stops trying to do it, and goto something else.
"On ERROR" wont work, since its not a error. "Try" doesnt work ether.
Its because I'm am programming something that can login to a router thought telnet, and sometimes the telnet ActiveX doesn't read the buffer or the line proberly, so when the .GetLine() func is called, it freezes. And i want away to goto another point if it keeps freezing for more than 5secounds. The telnet ActiveX that, I am using is Dimac w3sock.
I am looking for a library doing set operations on time periods with support of weekdays and time of day. I have started to roll my own, but it seems like a error-prone job so I would like a tested solution for this.I don't mind spending money. If I have a set of two time periods (this can be several)
I have created a windows service in C# .net and now I want it to alert me if its going to shutdown. For this I make use of Dispose/Unload events but now I want if the services are stopping due to system shutdown process it will alert me.
What I want to get from the algorithm is, to count the time that occured on the same period, e.g. on the time of 08.00, it's occured 46 event (see the yellow colored row).This is my algorithm:
Dim ColumnLength As Integer = GV.Rows.Count Dim TimeStart(ColumnLength - 1) As Integer Dim TimeEnd(ColumnLength - 1) As Integer[code]......
I am developing an application that prompts an user for doing certain tasks in a form. What i want is that a certain message should be popped for a certain amount of time and then close (probably say 2 seconds or so). I tried doing it with message boxes but they do not close on their own as they are designed to be modal (to wait for user command ). i do not want to display the text in a textbox of listbox. Is there a certain way i could do this.
I have looked through couple of threads about making the trial application to be expired within certain time. Most of the advice is to set a timer and store it in somewhere in the system with encrytion. Then later decrypt and compare with the date installed in the system.
I know about DateDiff and TimeSpan. I am doing a project. I save a date in the registry. Now, I have to test this date against today's date and calculate the differences in minutes, hours, days, months, weeks and years.
I save the date in the registry like this: Application.UserAppDataRegistry.SetValue("Date", [Date])
I then made a sub to calculate the differences: Private Sub Calculate() Try Dim DateGen As Date DateGen = CType([Date], Date) Select Case TimePeriod [Code] .....
As you can see, based on the difference between these dates ( today's date and the registry date ), a sub gets called and the program continues. Unfortunately, the minutes and hours never calls the RandomAlpha sub. How can I calculate the difference in minutes, hours etc.????
I have developed a system which i want my client to use for trial purpose for 1 month. i want a software or an idea to time the system for that period after which it should cease to work.
