VS 2008 Updating Controls Via SynchronizationContext Class?
Dec 15, 2010
I'm trying to update the UI from a background thread without invoking the control. Mainly because I've tried to do so and it never worked from a class. It worked just fine within the form class, but froze up in the class. I didn't receive any errors, it just lost its multi-threaded-ness.
I'm having a similar problem with using the SynchronizationContext class. I made a quick example to test if this would work how I think it should:
[Code]....
There's very little information on MSDN about this class in general and every example on the web I've seen so far, has nothing to do with classes.
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Mar 3, 2011
VB.NET 2010, .NET 4This might be a dumb question but I'm wondering what is special about the SendOrPostCallback delegate that is the first argument in indowsFormsSynchronizationContext's Send and Post methods? In other words, I can do the following:
SyncContext.Send(Sub() ..some work.., Nothing)
And that works (SyncContext is a WindowsFormsSynchronizationContext object). Why might it be preferable to do:
[code]....
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Sep 29, 2009
I need to write a quick function that sends two data items back to the UI thread... with the post/send commands I only see the ability to send one piece of information. Is there a way to do this by overriding these functions?
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Apr 22, 2010
I have a program written with VB.NET 2008 that includes a large number of dynamic controls in a form. When I drag the corner of my form, I want to resize every controls according to the new form size. It works very well, except that the controls are repainted one by one, instead of waiting at the end of my fonction and do a single repaint.
I did a lot of research on the NET without any good results:
- "Form1.DoubleBuffered = true" does not have any effect
- "Form1.SuspendLayout" does not have any effect
- "SendMessage(Me.Handle, WM_SETREDRAW, New IntPtr(CInt(False)), IntPtr.Zero)" suspended repaints but left the entire window messy.
I am running out of ideas. Here is a sample module to test if your trick works. Just try to resize the form, you will see how long it takes to repaint every control one by one:
[Code]...
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Dec 28, 2011
I've got a bunch of labels that I update regularly in the program, resulting in lagg, which is bad, so how can I update the labels in a thread?
When I try
Thread = New System.Threading.Thread(AddressOf ShowInfo)
Thread.Start()
[Code]......
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May 24, 2012
I have a custom control which I add a number of to a flowlayoutpanel:
Dim drive As New WindowsControlLibrary1.UserControl1()
drive.FileSystemlable = reader.GetString(2)
drive.AbalableSpaceLable = Convert.ToInt32(reader.GetString(4) / 1024)
drive.TotalSpaceLable = Convert.ToInt32(reader.GetString(5) / 1024)
drive.SetVolumeLable = reader.GetString(3)
[Code]...
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Oct 31, 2011
I'm having trouble getting controls in non active tabs to update. I have a tab control with 12 tabs. Each tab displays a custom calendar of days for each month. For each of the days I used label controls. Now the trouble im having is when I re-size the window I want the day labels in each tab to re-size accordingly. I have the re-size function written and working but for some reason it will only re-size the active tab. In order for me to have the labels on the other tabs update to the re-size I need to open each tab as to load it then it will update the controls.I've tried putting Application.DoEvents() in my re-size loop but that didn't work. How can I get the other tabs to update / redraw the controls without having to open the tabs first?
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Nov 1, 2010
I have a form with many controls that are binded to a datasource. when some of these values change, they impact aspects of the form itself like the backgroud color or the title. There is a filter applied to it so it only displays certain records (this is important).when I change something and save the data I need to update the filter to show all the previous records plus the current one.All that works great, but the problem is: saving the data or changing the filter makes the controls take a new value based on the new record and go through the subs that each one have to modify the aspect of the form. This happens because if I save the data first, then the current record does not conform to the filter and all the data in the form changes, or if I change the filter first, we go to the first record of the set.
After that I return to the correct record and everything looks fine, but going to all the changes makes the app halt for a moment.Is there a way that I can stop the controls in the form form updating to their binding data while saving or changing the filter in the bindingsource?
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Feb 3, 2009
I have created a dynamic form and have added several textboxes controls giving them names such as tb1, tb2 etc. The form is create and displayed, however cannot update the value of the controls.
Private WithEvents gform As New GenerateForm
The form is created using the following from click event of a button
Dim x As Boolean = gform.myForm("AForm") -- Form get created and displayed
x = gform.PopulateForm("a test message") -- The value is passed but not displayed
Public Class GenerateForm
Dim tbMsg As New TextBox()
[Code] .....
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Aug 25, 2009
Using MSDN documentation on creating Control Arrays in VB.net I proceeded to create a control array based on my UserControl. I modified the code programmatically to Loop through a For-Next loop to create 6 objects using the same UserControl. After creating these objects, I proceed to perform graphics on each control to draw a rectangle of which is in the center of the control by using a Timer_Tick event.
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Jan 8, 2011
I have a module that handles adding controls and populating values on a form. One of the controls is a button (there can be many) which acts as a lookup. For some reason, when I click the Button, it winds up in the btnLookup_Click event and displays the various messages, but it does not update the label (labLookup) text on the form. Am I missing something?
[Code]...
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Jun 2, 2012
I have created a new class with a string property called "Text".
The property will hold a sentence typed by the user.
I use "KeyPress" event to get the character pressed and use "Console.Text = Console.Text & e.KeyChar" to update the property. Where console is an instance of the class.
The problem is when I press "Delete" nothing happen.
That's the code within the event scope
MsgBox(Asc(e.KeyChar))
Console.Text = Console.Text & e.KeyChar
MsgBox(Console.Text)
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Jan 4, 2011
I have a Master List in the DataGrid that displays all the "Monitors" - think of them as Audits (for context). Basically when a user clicks on a row in the DataGrid the TextBoxes, ComboBoxes, CheckBoxes and DatePickers all show the values and the user can edit them there and that all reflects in the DataGrid just fine.How do i go about using the same TextBoxes, ComboBoxes, CheckBoxes and DatePickers to add a new record?
<Monitor.VB>
Public Class Monitor
Public Property MID As Integer
Public Property FileNumber As String
[code]....
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Feb 17, 2010
I have a vb.net class with properties defined as follows:
Private m_Property1 As String
Public Property Property1() As String
Get
[Code].....
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May 5, 2012
I have a class in vb.net defined as public class A
class A is created on Load and gets called once per program loop
The constructor for class A includes the argument (byref Value as long)
I have a global variable called varB that is passed to class A on creation.
now why when varB is altered during the program loop, the change is not reflected within the class?
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Nov 2, 2011
I've been programming in vb.NET for a whileAnd to be honest, its turning out to be a real pain.Here is the
Form1.vb: Imports System.Threading
Public Class Form1
Dim trd As Thread[code].....
So, I have a form (form1) with a label on, this label simply reports the status of the thread.The thread begins the Class1.Main() sub, and I have a delegate setup to change the text propoerty of the label.Now,I know the label is created on the UI thread,so I assumed the delegate would work. However,it seems that it updates the .text property, but doesnt redraw the control when .Update() is called .What am I doing wrong?I have found lots of examples of delegates, but all run from within the same class. I want to use threads too, not a backgroundworker! This code is a "simplified" version of a project I am on, which is encountering the same problems
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Oct 1, 2011
I am trying to use several Class arrays to hold values that I will cycle through at a later point to perform some calculations. I need to change the array sizes to fit the data as it is entered. I am using one procedure to set the first element of each array and then a separate procedure to pass the additional values as they are entered.
Until my last attempt at changing my code, my StartBalance sub seemed to work, I could step through and see the values assigned to the class arrays in the code block. However, when it moved on to the Transaction sub, it did not recognize that the first set of values were set, the array shows zero values for index 1.
I have gone through several changes trying different ideas from reading blogs and articles, but I guess I am not understanding how these work. I even used the class arrays directly instead of the Property procedures to see if I would get a different result, but I do not.
I believe I must be approaching this incorrectly and though I can find dozens of examples of setting class variables and even a couple on using arrays as class variable, I can not find any that show how to then pass values to those arrays.
Public Class Statement
Private _tranDate(1) As Date
Private _amount(1) As Double
[Code]....
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May 19, 2010
I have got problem when using the SQLCommandBuilder class. For me it throws an error saying that the select statement does not return any primary columns.... Which is weird becouse i am sure it does since the select statement is "SELECT * FROM MyTable" I am prety sure that selects everything including the primary column which is set to primary , realy i checked and doublechecked.
Secondly i tried to manually set the column(0) as primary by setting it's property bu no such luck of making it work.
I have these two functions in a class that i instanciate an object from in the main program:
Code:
Public Function GetDB(ByVal DBName As String) As Data.DataSetDim SQLAdapter As SqlClient.SqlDataAdapter = Nothing
Try_SQLdataSet = Nothing
[CODE]...
This Functtion fills the dataset and returns it to my main program where i do lovely stuff with it. (Just as a side note this is a SCADA system and i always need the entire DB which is never bigger then just a few ( 6 ) entries so i must go for "*" ^^). Good part is, this works like a charm, i love it. Now i need to reset a few status bits etc and i assume with the update command. And that is where my joy starts to get stomped on a bit.... The code:
Code:
Public Function SetDB(ByVal dataTable As Data.DataSet, ByVal DBName As String) As BooleanDim SQLAdapter As SqlClient.SqlDataAdapter = Nothing
Dim SQLCommandBuilder As SqlClient.SqlCommandBuilder
[CODE]...
Now this would have been a great and small sollution to updating datasets with the server but obviously it doesn't work. There is that pesky error about my table having no primary key and I know it's lying it just want to annoy me :P. But seriously I am puzzeld why that error wont go away and i have exhausted all the tutorials i can find on this.
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Sep 24, 2010
I'm having an issue where my main form isn't updating even though I see the event fire off. Let me explain the situation and share some of my code which I'm sure will be horrible since I'm an amateur. I created a class to take in the settings for running a process in the background. I add some custom events in that class so I could use that in my form instead of a timer.
[Code]...
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Sep 16, 2009
How do I define the controls from another class? Here is my code (highlighted) -
Imports System.Windows.Forms
Namespace Bryanlgh.Echo.Views
Namespace Bryanlgh.Core.Tasks
[Code]....
I also tried using Imports Bryanlgh.Echo.Views instead of Namespace and it also came up with 3 error messages -
1. Namespace or type specified in the Imports ' Bryanlgh.Echo.Views' doesn�t contain a public member or cannot be found.
2. Name 'cboPcpMd is not declared.
3. Name 'cboPhysicianPerforming' is not declared
How should I define these controls?
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Oct 13, 2011
I'm writing an app that pulls information from a DataSet as a one-way thing (e.g. the datasource populates a listbox, but for selection purposes only -- the user cannot change the list values). My problem is, when I select something from the listbox, all of the other listboxes change too, as if the control is telling the others "Update your contents to display what is in row 5"
[Code]...
I then use the IDE to bind lstOne and lstTwo (both listboxes) to datInfo, and use the DisplayMember to bind lstOne to colOne and lstTwo to colTwo.When I run and click on a value in one listbox, the other one follows suit. For example if I click on "One Three" in lstOne, lstTwo displays "Two Three". I expect to click on "One Three" then be able to independently set lstTwo to "Two One"
This seems counter-intuitive, so is there a way to do what I'm after from the IDE, or will I have to do it all from code?
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Sep 6, 2009
Sometimes when updating the entire screen or moving around controls etc, there is some fairly bad screen flickering.
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Jun 10, 2012
Create a web browser with tabs and I want to add a "Open in a new Link" Button with a Custom Menu .
The problem is I'm trying to use a Dynamic Control(Webbrowser) created in a class from a local sub (A picture box) on the event click . But i get this error [code]....
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Mar 20, 2009
I have yet to find a "nice" way to do two way databinding in .Net. The one thing I don't like for example in the present asp.net two way databinding is doing the binding in the aspx page is no compile time checking, ie:
<asp:TextBox ID="TitleTextBox"
runat="server" Text='<%# Bind("Title_oops_spelled_wrong") %>'>
I would like to have something like this:
Class Binder
Public Sub BindControl(ctl As Control, objectProperty As ???????)
'// Add ctl and objectProperty to a collection
End Sub
What I don't know is possible is, how to receive the objectProperty in my example; I want to receive a reference (ie: a pointer) to the property, so later, via this reference, I can either read from or write to the property.
Can this somehow be done with delegates perhaps??
UPDATE: Note, I want to add the control reference to a binding collection, this collection would then be used for binding and unbinding.
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Jul 2, 2010
<edit on 7th July, 2010. Please see my 4th post in this threadfor the reason I have marked the post by bpellAS ANSWER </edit>
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Jan 31, 2010
I guess this is a general question say I have created a taskpanel class and I have text space in a footer I created. How would I refer to say a button that may or may not have been put on their at design time. I have code like this:-Private Sub Button1_MouseEnter(ByVal sender As System.Object, ByVal e As System.EventArgs)
Dim rv As String
rv = ToolTip1.GetToolTip(Button1)
BorderContainerGood1._BorderDetails.footerDetails.Text = rv
[code]......
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Jan 11, 2012
How to access controls from class files in app code?
Markup:
<%@ Page Language="vb" AutoEventWireup="false" Inherits="shoppingCart1.ShoppingPage" CodeFile="ShoppingPage.aspx.vb" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
[Code]...
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Dec 22, 2011
I have a lot of controls on my asp.net web form that require validation. Rather than list each control in the code behind page that requires validating I would like to add the css class "required" to the necessary controls and then on submit the code behind will validate each control with this class. I'm fairly new to .net so here is some Pseudo code:
Public Sub ValidateAllControls(ByVal a As Object)
For Each c As Control In a.Controls
If c.Controls.Count > 0 And c.Controls.class = "required" Then
[code]....
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May 15, 2012
In my code I use two classes. One contains the UI form, the other containsa method to write to a file. During coding I found out some behaviourwhich I don't understand. The code below shows (what I believe to be)the relevant part. The file writing part is substituted by a MsgBox for simplicity.I have the following controls in one form:
NumericUpDown
Button
With the following classes and methods:
[code].....
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Jan 21, 2011
I am rather irritated at this. I have no clue why looping through controls on a form and in groupboxes leaves out 75% of the controls.
Here's the code I have:
Dim settings As String = ""
Dim gbControl As Control
Dim gbbox As Control
[Code]....
I want to have setting save all settings to an ini file, and not have to reprogram the saving routine when I add a group box or control. At random times, any number of controls can be disabled, checkboxes can be checked and unchecked, radiobuttons can be checked and unchecked. Regardless of the state of the control, I want the control to show up in the loop. But they don't. Only controls that are enabled and only checkboxes that are checked, every other control state is ignored. That's crap, and is definitely not what is needed by any programmer of any type. We're capable of determining if a control is enabled, hidden, checked, visible, and otherwise.
How do I get the controls to be included in the loop regardless of their state?
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