Adding Item To A Listbox From A System.Timer
Oct 1, 2009
For the last couple of days I been trying to add items to a listbox from another class within a system.timer.
They just don't appear in the listbox. I don't get any errors. The items just don't get added :S.
I have:
Form.vb
make object of Control
Control.vb
Here I have a system.timer
In the Timer_Elapsed method I do this: form.listbox1.items.add("hello")
But it just doesn't work... When I add a new item to the listbox1 from the constructor or another method that has nothing to do with the timer it works...
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Jan 26, 2009
I cannot figure out how to add an item to a listbox with a specific value. I am able to add a text description without any problems, but how can I give it a specific value?
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Dec 23, 2009
This is what I have so farPublic Class Form1Private Sub IndividualParticularsBindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e s System.EventArgs) Handles IndividualParticularsBindingNa
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Feb 10, 2009
I have been out of VB since VB 6, but am back into it to write a basic app. I have created a listbox and am able to add data to it from a textbox via a command button. However, I want to give the user the option to simply press the enter key after they have entered the info the textbox, instead of clicking on the command button. I tried calling the function the command button is using from the "ENTER" event on the textbox, but all that does is execute the function when I click on the textbox? I'm sure this is very simple. What am I missing?
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Sep 8, 2009
How do you add an item to the system context menu? I would like to let my users be able to right click anywhere and launch this program. I cannot seem to find it documented anywhere either.
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Jun 26, 2006
Adding an item to the System Menu in WinForms
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Jun 15, 2009
I'm wondering what exactly is the difference System.Timers.Timer and System.Windows.Forms.Timer???
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Sep 8, 2011
How would one go about checking a listbox's items for duplicates? Basically I need to write a program that displays the teams from a text file provided by my instructor, in alphabetical order. I can do that, but what I can't figure out is how to prevent the For loop from adding a duplicate team. What I'm envisioning is:
If teams(i).name is not in lstTeams.Items Then
lstTeams.Items.Add(teams(i).name)
End If
I have a program that compiles and works so far, except for the above problem and my alphabetical order (which I can probably figure out on my own:
Public Class danbrockteams
Structure team
Dim name As String
[Code]....
This works except that my listbox is filled with the team every player is in rather than just listing all possible teams. Not exactly looking for someone to just give me the answer, as I understand things best when figuring them out on my own, so I suppose a hint is what I'm really after.
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Feb 3, 2010
I'm working with a listbox that has, let's say, 20 items. The size of the listbox allows the user to see the first 5 items. However, the listbox has one preselected item which is sometimes not visible because it isn't one of the first 5 items.
After I set the selected Item for the listbox how can I ensure that the lisbox is scrolled appropriately so that the selected item is visible to the user?
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Jan 15, 2009
I need an accurate timer to interface a Windows application to a piece of lab equipment.I used System.Timers.Timer() to create a timer that ticks every 10 msec, but this clock runs slow. For example 1000 ticks with an interval of 10 msec should take 10 wall-clock seconds, but it actually takes more like 20 wall-clock sec (on my PC). I am guessing this is because System.Timers.Timer() is an interval timer that is reset every time it elapses. Since it will always take some time between when the timer elapses and when it is reset (to another 10msec) the clock will run slow. This probably fine if the interval is large (seconds or minutes) but unacceptable for very short intervals.Is there a function on Windows that will trigger a procedure every time the system clock crosses a 10 msec (or whatever) boundary?
UPDATE: System.Timers.Timer() is extremely inaccurate for small intervals.I wrote a simple program that counted 10 seconds several ways:
Interval=1, Count=10000, Run time = 160 sec, msec per interval=16
Interval=10, Count=1000, Run time = 16 sec, msec per interval=15
Interval=100, Count=100, Run time = 11 sec, msec per interval=110
Interval=1000, Count=10, Run time = 10 sec, msec per interval=1000
It seems like System.Timers.Timer() cannot tick faster that about 15 msec, regardless of the interval setting.Note that none of these tests seemed to use any measurable CPU time, so the limit is not the CPU, just a .net limitation (bug?)For now I think I can live with an inaccurate timer that triggers a routine every 15 msec or so and the routine gets an accurate system time. Kinda strange, but...I also found a shareware product ZylTimer.NET that claims to be a much more accurate .net timer (resolution of 1-2 msec). This may be what I need. If there is one product there are likely others.
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Jul 5, 2010
In my application I have a listbox and SelectionMode should be MultiSimple because users need to see which items they selected. In another tab we have another listbox this one should show all the selection users had done in first tab. Private Sub
[Code]....
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Apr 4, 2012
Here is the stack trace:
2012-03-16 19:15:09Z E System.NullReferenceException: Object reference not set to an instance of an object.
at System.Timers.Timer.set_Enabled(Boolean value)
at System.Timers.Timer.Stop()
Here's the code:
Timer declared as private member variable.
Private _myTimer As System.Timers.Timer
Initialize timer method.
[code]....
The timer has to have a value or else the Timer.Stop() call would be throwing the exception. This is a sporadic error and I'm just trying to see if anyone has experienced this before or if anyone has any ideas of what could be causing it. It is occuring in a WinForms application in the event handler for the Elapsed event of the Timer, but it is only occuring sporadically on the users computer. I haven't been able to reproduce the error myself.
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Oct 13, 2011
How someone would select an item from a list box and click a button and have that item go into another listbox with it's price? I seem to be stuck on this part.
Here's my code:
I want to select the first option from the first listbox and I want to put it into another listbox along with the price of that item on the same line in the listbox. I can't seem to figure out how to that.
Public Class Form1
Const dcmPRICE_STRESS As Decimal = CDec(595.0)
Const dcmPRICE_TIME_MANAGMENT As Decimal = 695
[CODE]...
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Jan 12, 2012
removing Listbox item from checked Listview item.The code I tried just errors out.
Private Sub ListView1_ItemCheck(sender As Object, e As System.Windows.Forms.ItemCheckEventArgs) Handles ListView1.ItemCheck
If (e.CurrentValue = CheckState.Unchecked) Then
ListBox1.Items.Add(Me.ListView1.Items(e.Index).Text)
ElseIf (e.CurrentValue = CheckState.Checked) Then
[Code]...
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Aug 7, 2010
Is it possible to select an item in one listbox and then display the data of another listbox with the same indexed position? I am planning a project and this is something I would like to attempt but I haven't figured out how to do it.[code..]
I tried doing the above code but instead of displaying the listbox text the message box just returned false.
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May 26, 2011
problem that i am facing is i want to add array of object as a single item in listbox. in vb6 i was using this Label1.Caption = Label1.Caption & Mid$ (strInput, intI, 1) & " " List1.AddItem (Label1.Caption) i was using label. caption to store object but not work in vs2008 because label.text only take text and left other values
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Dec 9, 2011
I am trying to change an item in a selected item of a listbox.
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Jul 17, 2009
I need some code that goes through each item in a listbox and executes a for next loop for each item
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Feb 1, 2010
I have 2 listboxes on my form.Listbox 1 - populated with "available" field namesListbox 2 - populated with "selected" field names.There cannot be the same field name in both listboxes - it's either one of the other.The logic I was going to apply was to populate Listbox 1 with every field name ... and then as I populated Listbox with the field names which the user has already selected, remove the corresponding item from Listbox 1.
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Apr 22, 2012
I have got my timer ticking but I need to add the leading zero back in but it code I am using only works on the seconds (label3) not on the minutes (label4)!
Timer
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Label3.Text -= 1
If Label3.Text = "00" Then
Label4.Text -= 1
[Code] .....
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May 9, 2012
how to add listbox item to another,when listbox r created dynamically.
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Nov 24, 2011
Just want to ask this. I have a jQuery that move listbox item to another listbox. An its working fine the item was remove. Sample: I remove item in listbox A and it was added to listbox B. But here is now the problem, when I tried to check each item in listbox A, I noticed that all items that was removed was still there. But i can see in my eyes that it was removed. but when I tried to run a code to check each items - all item that was removed was still there.
[Code]...
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Apr 17, 2009
I have an application that i have developed which requires me to run a method in one of the classes on a timely basis. Basically, calling the method at an interval.I can do this if there's only a single object, but the number of objects that i have to create depends on the number of entries in a table. I was wondering if it's possible to add timer control dynamically and make the tick even call objects' methods at an interval.
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Apr 26, 2009
Visual Basic Express Edition 2008 Problem. I have a Combo Box containing Country Names "New York" & "New Zealand", when "New York" is selected it shows the time and date of New York in label1 on the form and the time is updated every second by the timer, but when I make another selection by selecting New Zealand in the combox dropdown list then New York's time updation is stopped in label 1 and only New Zealand's time is updated in label 2. Why the timer control stops functioning for the first selection after we make a second selection in the combo box. I want that time for both label 1 country as well as label 2 country updates simultaneously on the form. My code is as follows:I have added 2 label controls and one combo box control on the form and following code.[code]Can any one advice me how all countries selected in the combo box one after other are dispplayed with updated time every second?
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Jan 21, 2009
switching back to the code causes an error dialog to pop up with the message:"An error was encountered during code generation.The changes you have made in the designer have not been committed to the source code.it is recommended that you close and reopen the source file.The error message follows: Error HRESULT E_FAIL has been returned from a call to a COM component."The source code the Designer
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Jul 21, 2009
i have a timer that counts down from 2 hours, its part of a 2 hour time limit for a computer. but if the application was to fail it would restart from 2 hours again. which isnt good, so it needs to restart where it left of. so far i have got it to save the current time on the countdown timer to a reg key. but i need to put that time back hope that made sense. here is the part of my code
Dim LLT As DateTime
Dim HReg1 As Object
HReg1 = CreateObject("Wscript.shell")
[Code]....
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Jan 4, 2011
I've tried a couple things to add items to a combobox (I've also Googled a lot but haven't found anything for VB2010) and on top of that, how to make it so that if the user selects 10ms, it changes the Timer1.Variable to 10.
Here is my progress from what I found on Google
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
ComboBox1.Items.Add("10ms")
[Code]....
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Nov 4, 2009
I have used system.timers.timer to watch several folders and move files in my windows service. But the timer event stops now and then. I have read that it is better to use system.threading.timer in services.This is my system.timers.timer
Private Timer As New System.Timers.Timer
AddHandler Timer.Elapsed, New System.Timers.ElapsedEventHandler(AddressOf Me.Timer_Elapsed)
Timer.Interval = 4000
Timer.Start()
[code]....
How do this code look like in system.threading.timer?How do i start and stop the timer using threading? That is very important because i stop the timer when it comes to the elapsed event and when the code har run it starts the timer again!
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Oct 27, 2010
In vb6 you used timer for the randomize seed.I noticed vb10 no longer uses it. Does this mean by default it uses the system timer for the seed?
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Mar 14, 2010
I need help writing an application which is a status changer. For testing purposes, I'm pulling each item in a list and displaying each to a message box. In reality, it won't be a message box. I'm using a FOR LOOP to accomplish this. [code]...
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