I have a Parent form that loads a child form and I only want to allow one instance of the child form. I have this on the button to open the form. Stepping through the code with the debugger it "appears" to work OK when the form is open (I say appears because nothing changes) but when the form is closed it doesn't open as I would expect. What am I missing?
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How do you check to see if a form is already loaded, ie if it is already loaded bring to the front else load the form.
View 3 Replieswell basically i created a new instance of Form1 because i do not like to use a default form instance. but of course doing so gives me 2 Form1s. is there anyway to stop the default form instance from being generated? [code]
View 11 Repliescreating single instance form in MDI Application. How to check whether form's instance created or not?
View 6 RepliesHow could i make sure that only one instance of a child form is loaded in my application.
View 3 Replieshow to PROPERLY make a multi-tabbed or multi-window application that can handle file start requests.
For example, on startup my "Desktop Application" runs and sits there waiting for a task, either through the main menu, or for a file to display in a window. Now the problem is simple, how can I make this already running program load the dropped file (dropped on the executable (!)), instead of starting a new instance.
I understand I will have to check if the process is running, and if so, do some stuff with it. But the problem is passing the message to the active program.
Previously I used text files with paths/arguments in them, but I don't like the idea of the OS/program checking every 500 ms if a file is created in the "load this" folder...
Then I thought of sending a message using "Send Message", for example changing the text in a textbox and handle the "Text Changed" event, but is this reliable? Can any other program interfere with it?
So, basically I need the proper way of doing all of this. For example, Microsoft Visual Studio does this nicely, and no lag whatsoever...
Is there a way to check if a form has been loaded yet? I saw in C# they have a isLoaded property, but it doesn't seem to exist in the VB.Net Form class?
View 17 RepliesI am making this program that has a loop that goes to a website and fills in a form within the loop. But first, here is my code thus far
Dim message As String = TextBox3.Text
Dim loopnumber As Integer = TextBox4.Text 'makes the necessary variables
Dim browser As New WebBrowser
Dim url As String
[Code] .....
But what happens is that the loop runs a few times then it errors on the setattribute line (line 19 above) with
NullRefrenceException was unhandled
And I have a feeling that it is not loading the page fully before it tries to fill in the form.
Is there a way to see if a particular frame within the webbrowser control is finished loading? I know the functions webbrowser1.isbusyandebbrowser1.readystate=readystate_complete work for the main window, but it does not work when a frame is loading. It simply keeps saying the page is done loading. The event webbrowser1_documentcompleted sort of works, it registers when my frame has loaded, but it also registers when all the other frames are loaded. Is there a way to just check on the status of one particular frame.
View 2 RepliesI need to check if my client is connected to the server by starting a new thread. So in short I need a way to know if the client is still connected to the server.
Here is my
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I am trying to set a form position before it shows but i cant get it working.Form Name: ColorCentraling.vb
I've tried: Private Sub ClickNPC_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ClickNPC.Tick
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are 2 integers which represent a number which does not need to be explained.There i've made a DIM as the form but new! I've tried settings its location but its not possible for me.I know this is possible because: I've visited many VB.NET 2008 Programs that do this
Ok so my main form takes around 5 seconds to load i can't make it so that my load subs are on a seperate thread because too many cross thread calls being made besides i want a splash screen anyway i want a splash screen on a seperate thread that can update status while main thread is loading this way main thread carries the load subs and invokes status label changes in the splash form which is on another thread
this is my code
Dim SPForm As SplashForm
Public Sub LoaderSub(ByVal Splashed As Boolean)
If Splashed = False Then
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what happens is the splash form shows and so does the main form but they both lag for 5 seconds (as if they are both on main thread) how do i make it so that the splash form loads from the new thread? I thought the way i did it that's what should happen...
EDIT: also why did code wraps failed to show proper vb code?
I have a "Please Wait..." form that I show when doing some long task. This works quite well. But I cannot seem to control the opening position of the form. Currently I am using:
WaitWindow.StartPosition = FormStartPosition.CenterParent
WaitWindow.Show()
and this is just being ignored. The window opens at random locations. If I change it to CenterScreen, that works! But I don't want it center screen, I want it centered on the parent. Can I manually set the location? I am using VB 2008 Express and the wait form is a plain windows form.
I have a very simple form with a combo box named txtRoomType bound to ROOMCODESBINDINGSOURCE and a DGV bound using ROOMPRICINGBINDINGSOURCE.
Public Class frmShowRoomPricing
Private Sub frmShowRoomPricing_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[Code]....
When I check the value of txtRoomCode when the form is loaded for a 2nd time it tells me it is blank, but there is a value in it. I think the fault is in the form_load, but I do not know why.
Is it possible in VB .NET to find out if a form is loaded? Also, is it possible to find out if a form is shown at the moment? I think for the second issue it's enough to get the value of the property of the form:
MyForm.Visible
However, I don't know how I could find out if a form is loaded or not.
Is it possible to run a function or to execute a button just after the form was loaded? I mean to execute it just as the form_load subroutine has ended, so the form is already being displayed.
View 2 RepliesI have coded in the older version of VB for years (VB6 and prior) and Recently I just began learning VB 2008. In my current project I made a mistake in a form name frmAuthors and so far I am unable to recover. The problem is that I tried to have the form inherit a class I had created (first mistake). The IDE generated a popup message stating the error and provided the option of changing from inheritance from system.windows.forms to the class I had created. I said yes just to see what would happen (I was bored so I was up for something new) and that's when the form got corrupted.Is there a way to let frmAuthors go back to recognizing itself as a form object and not a member of the object I had created?
View 2 RepliesOk I have a project which has a MDI parent. Inside the parent I have multiple isntances of a form load(frmLine1t5). When my program loads it will load a different form(frmSelect) and if I manually load a different form(frmRetests) I can put frmSelect on top of frmRetests and bring one another to the front if it's clicked on(without using the bringtofront method)However as soon as I load a single instance of frmLine1t5 I immediately can no longer bring ANY form loaded into the MDI parent(before or after frmLine1t5 has loaded) to the front. I can only bring them to print IF I use .bringtofront method
View 1 RepliesI am just wondering how to force the creation of a handle of a control before the form that it is contained on is loaded... I have tried:
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Using the webbrowser control and conditional logic, how would I check to see if a specific site has been loaded?
View 6 RepliesUsing VB.Net, how would I go about checking if a loaded page in a Web Browser object contains a certain line of text? Sorry if theres an obvious answer for this, I'm used to programming in Java.
View 1 RepliesI have a form which contains a tab control with three tabs on it. On a second tab there is a PictureBox. The problem is I can't figure out how to check if the PictureBox is completely loaded.I can't put "pictureBox.CreateGraphics.DrawRectangle(Pens.Aqua, 100, 100, 100, 100)" into a form load event because picturebox is not active until I click on the tab2. It neither works with tab2.enter event nor any other events I have tried so far. However it works through the button.click event and it works briefly with the picturebox.paint event before its wiped out. So I presume it will work with a timer event as well.But the question is how to to make it work without a button or a timer?
View 3 RepliesI have a form template on my IDE, I want to open a new instance of it depending on what button is clicked, how can I do this?
View 18 RepliesI am in the process of trying to build an app that will permit multiple instances of the same form be added to an mdiparent as seperate mdichildren. The reason for this is that the child's data is based on a sql table's row information. Thus child one shows requested data from row 1, child two shows requested data from row 3 etc.
I have this setup so that each child is its own seperate tab in a tabcontrol. My problem is that after the second instance of the child is created the form in the first tab is disappearing after the line:
child.midparent = me
I don't understand what is causing this.
Dim child As Form = Support
Dim tab1 As New TabPage
child.MdiParent = Me
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in Old vb/VBA, I am accustomed to doing THIS when I instance a form object (as in "pop-up"):
Private WithEvents SomePopUpForm As Form_PopUpForm
Private Sub cmdEdit_Click()
Set SomePopUpForm = New Form_SomePopUpForm
SomePopUpFOrm.Visible = True
End Sub
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I have a form that creates an instance of a New Class. The code is simple so there is no issues with the programming.
I can step through the code on the Main Form without issues. Stepping Into moves from 1 line to the next.
I can't seem to debug the code within the class though. I set breakpoints but "stepping into" doesn't work. The code gets executed, but it doesn't step through each instruction.
I've tried changing many of the options within Tools > Debug with no luck.
I've tried deleting files from bindebug and obdebug.
Not being able to debug my programs.
I have a program I've been working on for some time now and I'd like to try to streamline it somewhat. I have a main menu form that has a split panel, in the left panel is a treeview that displays forms you can open and when one is selected, it opens in a child window in the right panel. Each time I open form I called DWNForm, it does a series of dataset loads which are the populating items for a series of listviews.
What I would like to do is have these datasets load once during the mainMenu load and then have the DWNForm be able to access the datasets once it is called from the treeview selection.
I am trying to use a progressbar to show on main form and then finish when next form is loaded, I have got this code.
1. When I click on button, it must open next form, but the next form must only open when the data in my list box has been loaded from Access Databse. When I run my program, it only shows the progressbar and don't open the next form.
Main form code:
Public Class Main
Dim PB As ProgressBar
Private Sub main_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
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I'm trying to implement single instance application using mutex.the application can run only one instance from a given directory.i tried to implement it in Applicationsevents class but it's not working.I replicated it with a test harness with a single form.my ApplicationEvents.vb code:
Private Sub SingleInstanceCheck(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
Dim strLoc As String = Assembly.GetExecutingAssembly().Location
[code]....
it runs multiple instances.Things I am not able change:
1.project setting has "Enable Application framework" ticked
2. ApplicationEvents.vb handles UnhandleException which means i cant have a module as startup.
I'm wanting to add a some extra code within my application. My app is a single form that sets some environment variables before calling a one of two possible 3rd party executables to run. I have set via regedit the file association for files to open via my app but what I want to do is have my app check to see if either 3rd party app is already running. In short I'm trying to ensure either 3rd party app stays as a single instance.
If a user were to try an open another instance: 1) my application should simply terminate (no warnings, no msg boxes etc...) 2)the file that the user was trying to open should open within the existing instance of the 3rd party application. The problem is I don't quite know how to achieve both parts I imagine that this 'instance check' should happen as the first bit of code so that if no instance of either 3rd party app is found, then proceed with rest of my application. I have tested using some lines of code at the top of Sub New(). Here's what I have so far for checking for both 3rd party applications:
Public Sub New()
If IsProcessRunning("ustation") = True Then
Me.Close()
[code]....
This gives me an error when I debug (Cannot access a disposed object)