Imagine that I have a System.Windows.Forms.Timer with 1000 ms interval. If I call Timer.Start() method and after 500 ms I call again Timer.Start() what happens? The second Start call will reset the interval or not? Are there any side effects?
View 3 RepliesI have a System.Windows.Forms.Timer named "DialogBoxTimer" set up on a form. When the form loads, it has a command to stop the timer. I have a routine [SPDataRecd(...)] that handles SerialPort1.DataReceived from a serial port (modem). When it is activated by a modem event, I want it to start the timer [DialogBoxTimer.Start()], but it doesn't work.If the timer is running, SPDataRecd can *stop* the timer [DialogBoxTimer.Stop()], but it can't start a stopped timer.
View 6 RepliesI'm wondering what exactly is the difference System.Timers.Timer and System.Windows.Forms.Timer???
View 4 RepliesWhen I do this
Public Class cInherits : Inherits Panel
I get this: Base class 'System.Windows.Forms.Panel' specified for class 'MenuButton' cannot be different from the base class 'System.Windows.Forms.UserControl' of one of its other partial types.
How do I inherit?
Hello,
I'm writing a windows service and initially tried just using a regular System.Windows.Forms.Timer, but never saw it's tick event get fired in my debugger. From doing some research, it appeared that I needed to use the S ystem.Timers.Timer control instead. In order to make debugging easy, I set my timer interval to a really short value 1000 ms. I'm seeing some rather strange behavior, though. It appears that my timer control is creating multiple threads within my application, or is this just a bug in my debugger? I have an event handler for the Elapsed event like so:
[code]...
When I step through my code like this, it now appears to work as expected. Has anyone else run into this?
Does calling the Dispose method on a Windows.Forms.Timer call it's Stop method? Or should I stop the timer before I dispose it?
View 5 Repliesi have a problem with trying to get 2 forms to close at different times using a timer on each of the 2 forms.
This is my form layout:
Quote:
frmMain
Frm1
Frm2
Frm1 and Frm2 are identical to each other. FrmMain has 2 buttons on it. One button to call Frm1 and the other to call Frm2.Frm1 and Frm2 each has a timer. It counts down to 0 and then does a .close(). However, if i pause between clicking the second button they both seem to always disappears at the same time.I would do something like this...
Click on the first button (showing the Frm1 form)
wait about 10 secs...Click on the second button (showing the Frm2 form)they both are shown on screen...hen they both disappear at the same time.... which shouldn't happen since i clicked the Frm2 box 10 seconds AFTER Frm1... So Frm1 should hide before Frm2 does...but it does not.
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i have a problem with trying to get 2 forms to close at different times using a timer on each of the 2 forms. This is my form layout:
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how can i import System.Windows.Forms in my asp.net class file?
View 2 RepliesClass 'System.Windows.Forms.Label' cannot be indexed because it has no default property Really can't figure out why I'm getting this error... tried to google it but no success. Could anyone point out what I'm doing wrong? I'm sure it's something simple. The code in red is where the error occurs.
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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.
I'm writing a .NET CF (VBNET 2008 3.5 SP1) application, which has one master form, and it dynamically loads specific UserControls based on menu click, in a sort of framework idea. There are certain methods and properties these controls all need to work within the app. Right now I am doing this as an Interface, but this is aggravating as all get up, because some of the methods are optional, and yet I MUST implement them by the nature of interfaces.
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I have an object (a third component gridview) which is serializable, and I need a deep clone of this object. I have the following code which throws the exception."The type System.Windows.Forms.Control in assembly System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKey Token=b77a5c5 61934e089 is not serializable".So the gridview's base class is System.Windows.Forms.Control, which is not serializable. How can I get a deep clone from the gridview? [code]
View 5 RepliesI have the code which checks if there is a selected tab
Private Function GetBrowser() As WebBrowser
If TabControl1.SelectedTab IsNot Nothing Then
For Each c As Control In TabControl1.SelectedTab.Controls
If TypeOf (c) Is WebBrowser Then
Return c
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I have a windows forms application written in VB.NET which scrapes information from serveral web pages (who doesn't right)? Anyway, I am having problem with one particular site where partway through the page navigation my application hangs. When I press pause (or break) in the debugger, it stops on a call to System.Windows.Forms.Application.DoEvents.
Resuming execution shows that it really is stuck on this line (it does not reach the next line of code). It also hangs about the same point each time I run it (at least its consistent). Since System.Windows.Forms.Application.DoEvents yields to other threads on the same processor and then resumes execution of the current thread, I think the problem is that some other thread is not behaving well (not returning from some event handling code). I thought Windows 7 was pre-emptive, which makes me
doubt that theory but I really don't know.
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The program scrapes somewhere between 12 and 14 pages before it gets stuck on the call to DoEvents. Does anyone have a clue why this would happen? Why would any call to DoEvents hang?
With the following imported namespaces in my project :
Imports System.Windows.Forms
Imports System.Reflection
.. I cannot add..
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I have a panel with some controls in it (several textboxes, a slider, 2 buttons, and a small groupbox).. When I click a button, I want all of the textboxes within the panel to be readonly... So I have this code: [code] When I run it though, I get the following error:Unable to cast object of type 'System.Windows.Forms.Button' to type 'System.Windows.Forms.TextBox'.If I remove a button, it moves on to give me the same error but for a label..
View 4 RepliesIn my Windows Form's application, I enable and start a Windows Form's Timer for a state machine which interacts with various User Controls. In one part of the state machine where an external device is being rebooted, I need to disable the User Interface (a User Control's UI) for the time it takes the device to reboot. The problem exists in that once I use System.Threading.Sleep, the timer that fires the State Machine stops and never restarts. I even re-enabled the Timer and re-started it after the Sleep command but to no avail. Is this expected operation or should a Windows Form's Timer be able to restart after a Sleep?
Snippet of code from a step in the state machine below:
Cursor.Current = Cursors.WaitCursor
MainForm.Enabled = False
System.Threading.Thread.Sleep(8000)
MainForm.Enabled = True
Cursor.Current = Cursors.Default
MainForm.t1.Enabled = True
MainForm.t1.Start()
An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.Forms.dll it also says make sure you do not have infinate loop or infinate recursion il give all code in order that they are executed in Check the chechbox and it disables all irelevent stuff and populates the combobox
Private Sub CheckBox_Spray_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox_Spray.CheckedChanged
If Me.CheckBox_Spray.Checked = True Then
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I want to launch a java executable (let's call it MyApp.jar) from .Net using System.Diagnostics.Process.Start. What's the syntax in VB.Net? The command line syntax is this (if I recall it correctly - because i tried it a few days ago and it worked).
java.exe -jar MyApp.jar pathToSourceFile pathToDestFile
How do I run this command in VB.Net, using System.Diagnostics.Process.Start, assuming I have the following three string variables in VB.Net
pathToJavaExe
pathToSourceFile
pathToDestFile
We've been asked to make a program based on a spec where we enter some details and it will then output a graph.Part of the assignment asks us to set up a timer so that the bar chart will display each bar seperately with a time delay between each one.However the timer is assigned to a form (Form2) while the draw commands are within another class called Expenditure.
While the specification doesn't specifically say we should stop the timer from within the class it is implied.Now I have tried Form2.Timer1.Stop() and Form2.Timer1.Enabled = False within the class without any luck.I'm wondering is it possible for the Expenditure class to stop the timer or does it need to be done within Form2?
i need to get data from checkbox in a groupbox. in the groupbox, it also have a label. so my coding as below
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Whatever project I'm making, I always encounter a problem with a Windows Forms Timer control, I guess I just make a little mistake somewhere... So I thought I'd post it here and hopefully someone here can explain what I'm doing wrong.
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I am trying to use values from form1 in my project, in form2, but Im not sure how to do it. I've tried
txtboxTotal = (Form1.vsbLength * Form1.vsbWidth) * Pattern
But I get: operator '*' is not defined for types 'System.Windows.Forms.VscrollBar' and 'Systems.Windows.Forms.VscrollBar.'
Private Sub wb_Scrape(ByVal sender As System.Object, ByVal e As
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Win7 64 bit; fully patched VS2008 targeting FW2.0; VB.Net; running in Debug Mode (not tested in Release mode)I have a resonably complex app which I am refactoring a bit. As part of that, I relocated some code from a subroutine into a Click Event Handler. The Event Handler will, late in the handler, call the, reduced in function, subroutine. The point of this is thatNow when I click the button associated with the modified Handler I get:A first chance exception of type 'System.AccessViolationException' occurred in System.Windows.Forms.dll<br />With Error System.AccessViolationException Attempted to read or write protected memory.This is often an indication that other memory is corrupt.
at MusicManager2009.frmMain2.cmdLoadAlbum_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
[code].....
All functions of the app, except those that start from the buttonclick in question, work as before in the problem version.The problem persists after rebuilding the entire solution, after restarting VS, and after rebooting the PC.
When I run my project I get "An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.Forms.dll"
Public Class frmViewReport
Dim objForm As New frmViewReport
Private Sub frmViewReport_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
objForm.ViewReport("C:a2.rtp", , "@parameter1=test�mter2=10")
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I have the following code running, the first time I change the selected index, everything runs smoothly. However, if I try to change the selected index again, nothing happens and the subcategories combobox values do not change.
Private Sub cboMainCategory_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboMainCategory.SelectedIndexChanged
'* make sure the combobox is fully loaded
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I keep getting an eroor this error says: An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in system.windows.forms.dll Additional information: Specified argument was out of the range of valid values.
Option Strict On
Public Class frmWeeklyReport
Inherits System.Windows.Forms.Form
[code].....
A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll It displays in my Immediate Window when i run my program, I'm using a text reader to read a number of XML files using background worker...most the time it stops so something is wrong but sometimes it works fine.
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