When I write a byte array to a device using this code, the DataReceived Event never fires.....
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AND if the sleep is <40, the event doesn't fire. Is this necessary or am I overlooking something?
Im using VB express 2008 (compiled with .NET 3.5) to write a program that communicates with a USB device. The USB device is a communication class device and thus will emulate the usual rs232 serial port once attached to the PC. The USB device sends a fixed number of bytes and i have set the threshold received byte property to this value. I have run the program and it seems to read the USB device "correctly" but when i debug the code, i realise that the datareceived event of the serial port gets fired on the eventtype = EOF. I am using the Read function to read the bytes from the serial port and the Newline property is set to "" (but i thought that this is irrelevant if im not using ReadLine). When the datareceived event fires with EOF, the Read function blocks until one byte arrives, reads it and calls the function that processes the data. I went through the forum and realised that the EOF eventtype is no longer supported, is this true? I dont think that getting this eventtype is logical anyways in my case.
View 5 RepliesSo I just spent the last 4 hours trying to find out what was wrong with my code, just to find out that there's a bug in this version or I just don't have enough knowledge of VB2010 (I'm coming from VB6, this is my first program on 2010)I removed the rest of the code just to point out the problem, here it simply tries to enable the Timer1 when you receive data in the SerialPort1
Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
If Me.Timer1.Enabled = False Then
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After this I found that the code inside the Timer1 didn't run when the 100miliseconds passed, so I added a msgbox to see debug.
Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
If Me.Timer1.Enabled = False Then
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I've managed to make an application at home using a serialport emulator and connector that will read text from a file on my desktop send it to com1 and then my connector program will merge com1 with com2. In short my program works at home but when I connect it to my device it appears the data in DataReceived is a fraction of what my simulator setup at home is producing, which apparently is completely normal according to all these threads I've read here.
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Every 5 to 10 seconds I receive 5-12 bytes of data (confirmed w/Hyperterminal). I can open the com port(btn1), read bytes(btn3) until bytes to read = 0, but then i'm stuck; the data received event doesn't seem to respond. If I close the serial port(btn2), re-open i can read more data until bytes to read = 0 then stuck again. I tried several suggestions for threads and delegate and invoke but none worked. (WIndows XP, VB 2008)
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I have an application with serial port datareceived event. My instrument sends me aprox.00bytes every 1 second. Which I then process and update few textboxes on the main formRecently my application started crashing if I press close button.I am guessing form_closing closes serialport at the same time datareceived event triggers in which the sp1.bytestoread causes the crash.1. I added synclock in datareceived and in form_closing.Within synclock in form_closing I removed datareceived handler.
View 8 RepliesA form has many buttons. One of those buttons contains code to update the TableAdapterManager. One of the many TextBox controls has code in a Validating event handler. There is code to make sure a US phone number is formatted properly.If the user tabs out of the TextBox the Validating code works perfectly and show a message to the user if the phone number is not properly formatted and the focus is place in the offending TextBox.If the user clicks on a button that has code to update the TableAdapterManager the Validating code fires but instead of focus remaining on the offending TextBox, the code in the button Click handler also fires.
I would like to stop the button code from firing.Here is the code for the Validating event of the TextBox:
Private Sub TextBoxPrimaryPhone_Validating(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBoxPrimaryPhone.Validating
' Make sure the phone is formatted correctly.
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What additional coding to I need to include so focus remains on the TextBox?
I'm looking for a reference that can explain the concept and use of the DataReceived event and Delegates subject.The reference has to be pretty simple as I'm an "old dog attempting to learn a new trick". I'm not ignorant of things programming, but am ignorant of things dealing with serial communication in VB2005.I already have a couple of O'Rielly books ("VB2005 Cookbook", "VB2005 Desktop Reference") and I have a book that deals with serial communication from a Jan Axle-something. Neither O'Rielly books have any info, and the Axle-someting book's remotely related examples are too confusing for this slow learner.
View 6 RepliesI am trying to get a fairly simple Serial Port program working. So simple in fact I have been bashing my head over it for quite a while.
I have a piece of equipment connected over a null modem cable. When turned on, it just starts spitting data out RS232 and I need to capture it. Hyperterminal does see the data so the USB-serial converter is working.
When I run the code snippet included, the port opens fine, but the DataReceived event never fires.
Imports System.IO
Public Class Form1
Dim WithEvents serialPort As New IO.Ports.SerialPort
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I read data into a DS from an XML file. The user has the ability to "Save" or "Save As" at any time. They can also "Open" an existing file or create a "New" one. (brilliant, don't you think?)
I need to make sure I ask the user if they want to save their existing data (i.e. rewrite the XML file) if the DS has changed from the XML load or from the last time they Saved. On Open, New or exit I have been checking the HasChanges function on the DS. This doesn't work the way that I need. I use AcceptChanges throughout the program to commit values to the DS. This appears to kill the HasChanges even though the DS is now different than the XML file.
Is there an event in the DS that fires when data changes? If so, I believe I can set a flag that can be checked later. If not, is there any other way to track that a DS has changed after the initial XML load? Would reloading the XML into a cloned DS and comparing the two work? Seems like a waste of "time", especially with large XML files, but if it's the only way.
I have a class with two descendent classes (child, grandchild):[code]When a property changes in the Measurement class I raise a OnCrucibleOxidizedMassChanged event:[code]However, the OnChanged sub gets called twice, even though I only assign a value to CrucibleOxidizedMass once.
View 1 RepliesI have a problem with a ComboBox to select FontStyle. I need to select the font style twice to fire the event in SelectedIndexChanged Event, that means for example to click "Arial Black" twice to set the text to this font.
View 1 RepliesI'm looking for an event on a form that fires after Form.Load. Specifically, after the form has been displayed. Is there one?
View 3 Replieswhat event fires when individual textboxes that are bound to a data source using the properties pane gets refreshed? I wish to use this event to populate a few textboxes that are not bound.
View 1 RepliesI have a VB .NET form with a splitter control on it, and I want to save its position between program runs. I am currently handling the SplitterMoved event and storing the SplitterDistance. Then on program startup, I set the SplitterDistance to the saved value.
However, sometimes the program resizes the splitter, raising the SplitterMoved event and overwriting my saved distance. I have several splitters over multiple tabs in a tab control, and any time the user goes to a new tab for the first time, the SplitterMoved event fires.Is there an event I can use that will only fire when the user moves the splitter, and not when the program moves the splitter? I tried MouseUp, but when that event fires, the new SplitterDistance is not yet set.
The leave event fires twice in this example. Tab order for the form controls is set to combobox1, button1, button3 Private Sub ComboBox1_Leave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.Leave
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if I enter 'A' in the combobox1 then combobox1 leave event will fire twice any other entry is Ok since the next control to get focus is button2 (in the normal tab order).It seems that if I try to skip the next control (based on the tab order set for the form), the leave event fires twice.
I've been following a codeproject article on using the interop forms toolkit (basically a way for developers to slowly upgrade their VB6 projects to .net by allowing .net components run in VB6)
[URL]
While the .NET form is working fine in all other testing projects and environments, I've found that the Form_load event is actually firing twice once it's in executing in the VB6 runtime.Not only annoying, its forcing my initialization code to execute twice (causing all kind of problems on the second run).
If (runBefore = True) Then
I have a form for which the form load event only fires one time. When the program starts. It will not fire again until I end the program and restart. I have tried .show and .showdialog, but it acts the same. I have read about form load events loosing the handles, but my code looks exactly like it should.
Here is the load event code
PrivateSub frmBilling_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesMyBase.Load
LoadClients()
LoadTherapists()
LoadCPT() EndSub
Here is the code that calles the form.
PrivateSub BillingToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BillingToolStripMenuItem.ClickfrmBilling.Show()
frmbilling.show()
EndSub
I have a tree view with checkboxes. When a user checks an item in the tree, all items below it in the tree should be checked automatically to match the parent. The same is true is a user unchecks an item. That's been reasonably easy to implement using the after check event:-
Private Sub tvwUserGroups_AfterCheck(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles tvwUserGroups.AfterCheck
If Not m_Isloading _
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I want to change the background color of an element when the mouseEnter event fires. How to make the color of the background darker?? I thought I can use an opacity mask, but it's a gradient, but I need it to be solid. Also it has to be in visual basic code, not in xaml.
View 2 RepliesI have a ListView with the Activation property with HotTracking. There appears to be about a 2 second delay between when the user clicks the item and the event fires. Is there a way to get the event to fire immediately upon the user click?
View 2 RepliesI have a BackgroundWorker in a vb.net program that is doing a lengthy data import routine. I want to modify its RunWorkerAsync method so that it fires a custom event on completion of the method. (So that a method in an automated process can respond to the event and resume its work). In a sense I want to 'extend' the RunWorkerAsync method to add an extra line of code--but I can't 'see' the code in the method (to just add the line raising the event) because BackgroundWorker is an MSDN class from Microsoft.The only solution that I can think of is to 'wrap' the background worker class in a wrapper that calls the .RunWorkerAsync method and then raises the event.
Public sub wrapperMethod()
myBackgroundWorker.RunWorkerAsync()
raise customEvent
end sub
Is there a design pattern that I might use? An easy way to address this with the .net language?
PS: Unfortunately, I'm automating some clanking legacy software and backgroundworker is used in many locations, so wrapping the backgroundworker will be a bit of work and may open bugs.
At the top of my code for the form I have the following statements (and some other unrelated ones to):
Dim LastDataRow As DataRow
Public Event RowChanged As DataRowChangeEventHandler
When my form loads I run the following line of code:
AddHandler dt.RowChanged, New DataRowChangeEventHandler(AddressOf Row_Changed)
After the form loads I have a FetchData button which connects to the database and brings the records into a datatable object. During this fill operation my Row_Changed event fires (for every record I think) and tries to run DataAdapter.Update(DataTable) (pseudocode) which ultimately fails because I haven't yet created commands. The error I get in my Row_Changed procedure is:
Update requires a valid InsertCommand when passed DataRow collection with new rows.I hadn't even planned to use an InsertCommand at all since I will not be allowing users to insert records from this form. I do plan to allow them to delete or modify existing records, but not insert new ones.run my AddHandler statement after filling the datatable. However, I'm trying to figure out how to rewrite my code so that I can refresh the datatable without closing out the form/application and having to open it up again. I think that's a problem for a separate discussion.
Anyone know why the Mouse_Leave event fires when you don't leave the control with the mouse pointer?Put a large button on a Form so your mouse pointer does not leave it easily.Then try this codeWhen you do, leave the mouse pointer in the middle of the button and then click the button.By the way, if you uncomment the 1st line of code in the Button Click event and comment out the MessageBox, this does not happen.Can someone please explain this behaviour?
Option Strict On
Option Explicit On
Option Infer Off
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Based on our tests primarily done in VB.NET in VS2010 it seems that when you close a WinForm the "RowValidating" event of the DataGridView on that form behaves differently depending on whether the form is MODAL or NON-MODAL. What we did was open the form (MODAL and NONMODAL) and changed a value of a cell and then immediately clicked the "X" to close the form. It looks like the "RowValidating" event DOESN'T fire if the grid is on a MODAL form but it DOES fire when the grid is on a NON-MODAL form. We can't figure out why that is... Is this a known bug in .NET?
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I have a feature whereby a class in a dll displays a form asking a user to clear a fault on a printer before clicking a button to say "Retry".The users have been just hitting retry without bothering to clear the fault so I am now coding an interlock:The button on the invoked form is disabled until a call is made to an 'enable' method on the form.
This is done with delegate invocation as the events triggering these changes come from other dlls running on different threads.The form's 'enable' method is wired into an EVENT HANDLER handling an event coming in from a different thread (one that monitors an ethernet IO Server).The problem I have is that THE "_Fault_StateChanged" EVENT NEVER FIRES. I suspected the cause was the "ShowDialog" and "DialogResult" technique I have used here, but I have used this exact same technique elsewhere in this application.[code]....
I have set the controls mouse enter and mouse leave events. My problem is that the mouse leave event fires if I mouse over any of the child controls (like the name box for example).What I need is for the mouse leave event to fire when my mouse leaves the entire control, rather than firing when I mouse over any of the child controls. Here are the events as I have them so far:
Private Sub DeliveryControl_MouseEnter(sender As System.Object, e As System.EventArgs) Handles MyBase.MouseEnter
Me.removeImage.Visible = True
End Sub
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I was perhaps too quick to think that VB's built-in event would be be easy to use. As you can see from my previous post I am building a program which sends and receives a few bytes from serial bus. The bus is actually a usb serial adapter, there are no real serial buses in my machine.Anyway that SerialPort1.DataReceived does not fire. It is from visual studio/vb ide so syntax should work? Here is my start up code. There are many comments, because I tried various combinations.
If Not _serialPort.IsOpen Then
If Not arvo = "" Then
_serialPort.DtrEnable = False
_serialPort.Parity = Parity.None
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I am using a combo box on a form in vb net 2008. I would like the user to be able to either tab to the control and then select an
item OR the user could click on the combo box and then select the item.
unfortunately it fires twice when the user clicks on the control. This is before any items are selected. I have tried placing it in mouse down , focus , key down etc etc.
It does not fire twice for the enter event so I tried to use that alone, but then there is no dropping down of the combo box when the user clicks on the control. Is there a way to release the combo box enter event on the mouse click event?
I am trying to wait for the webbrowsers page to have finished loading to then carry out the next part of my code.However i am having problems because the DocumentCompleted event fires twice?
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