I know that in primitive versions of vb (as found in excel) there was a line that you could insert t prevent screens from flickering to and fro when it is trying to process something.Application.screenupdating = false
View 4 RepliesSometimes when updating the entire screen or moving around controls etc, there is some fairly bad screen flickering.
View 2 RepliesI am using this code for syntax highlighting in RTB and it works pretty nicely except for the flickering part.
VB.Net
Private Sub txt_source_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txt_source.TextChanged
Dim words As New List(Of String)
words.Add("<p>")
words.Add("</p>")
[Code]...
How would I prevent Rich Text Box from flickering?
I'm writing a simple paint program in VB 2008 that allows the user to create rectangles using MouseDown event to anchor one corner, MouseMove to stretch (or grow) the rectangle, then MouseUp event to complete the rectangle.The last statement in the MouseDown event is Me.Invalidate() to trigger the form's paint event where all the rectangles are drawn (refreshed).
View 1 RepliesJust finishing off an update to an application written in VB.NET that used to run fine under CE.NET 4.2. Deployment platform is now Windows Mobile 6.1. The application runs in full screen, however whenever a new form is opened, the task bar, i.e. the bar with the start button comes to the fore and then the new form takes over. This is particularly annoying as I have a form that has many sub forms which are 128,128 and still the task bar flashes and obscures part of the user input screen
View 2 RepliesDoes anyone know what causes and more importantly how to prevent the flickering you come by when painting a control?
View 3 RepliesI have a htpc project that I am working on. The main program loads dll plugins which are basically other win forms. On each of these forms, including the main program, I use a picturebox (a double buffered picturebox) for the background image and then draw everything on it by hand. Whenever I load the form from the dll and show it, I get a weird flicker. It looks like it is the previously used double buffer. Is there any way to clear the background double buffer before the flicker? Or am I going in the wrong direction?
Here's a couple of videos of the problem:
[url]
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Notice the black screen with the white lines on it or the flash of the desktop after I click "Movies." How do I get rid of that?
I have a textbox1.textchanged event in my application.. so when I start typing into the textbox, it looks up the value of what I'm typing against a dataset. There is a datagrid in my application as well, and if i click a cell in the datagrid, it pastes a value into that textbox... when this happens, I don't want the textbox to do look up the value against the db.. I just want it to paste into the textbox without any further action..
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I have a TreeView object on my form, with check boxes. By the way, I'm working with vb.NET. I want it to perform a few different things with the aftercheck event:
If you check a node, check all its children
If you uncheck a node, uncheck the parent node
If you uncheck a node, uncheck all its children
The problem is when you uncheck a node, it unchecks its parent node, which triggers the event again and unchecks all its children.
Would there be a way to prevent the event from triggering a second time? Or will I have to give up on one of those two points?
Here's the code, if it helps any:
If e.Node.Level > 0 Then
If e.Node.Checked = False Then
If e.Node.Parent.Checked = True Then
[code]....
While I'm at it, is there a way to check if a folder is accessible? I've toyed with FileAttributes, but can't seem to find out how to make it work...
Is there a way to prevent the SelectionChanged event from firing when adding rows to a DGV programatically? I am adding rows in a loop & the SelectionChanged event fires twice, which is causing me problems. I only want it to fire when the user clicks on a row.
View 9 RepliesI would like this ASP button control to stop calling its event handler when the JavaScript client method IsCorrectPrice() returns false.
<asp:Button ID="btnsubmit" runat="server"
Text="Submit" OnClientClick="javascript:IsCorrectPrice()"/>
btnsubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Handles btnsubmit.Click
Every time I refresh the browser, my button's event handler fires again. How do you prevent this?
View 2 RepliesI have a form contains NumericUpDown1, TextBox1, TextBox2, at design time i set NumericUpDown1.Value to 4 and TextBox2.Text to 100, and i have this sub[code]...
View 13 RepliesI'm trying to prevent a sub / function from firing multiple times on the same event.My app is for handling inbound phone calls (tapi).The app is supposed to route calls based on the callerid number.
aircode below:
Code:
Private Sub OnNewCall(ByVal sender As Object, ByVal e As NewCallEventArgs) Handles tapiManager.NewCall
if newcall.callerid = "5551001" then
redirect(newcall)
[code]....
If callA.callerid = "5551001" then redirect(callA)but, once it is redirected to the new extension, do not then grab the call from the new extension and try to redirect again (resulting in infinite loop).I realize I could use an integer as a counter, but the problem is, I might actually get more than 1 call at the same time from the same callerid number. And, all the calls would need to be redirected (once).the calls do have properties like (which are unique identifiers to each call):
Code:
phcall.id and phcall.hashcode
I'm thinking I need to put that unique id into a temp var / array to run a check against to see if it has been redirected, if it has then skip, if it has not then redirect.The app would run 24x7, and I don't want the temp var / array to get too big, and would want to have it clean automatically (up on a timer maybe?)(I'm guessing it would be a dynamically growing array.)
I designed a DataGridView under the name "dgvTarifa" and took a chance on trying Row Validating (tried Validated, CellEnter, CellLeave, RowEnter, RowLeave all count same) event. The purpose of the code is to load the selected values of the respective columns into three textboxes in order to rephrase/revalue those and update them by pressing a button. All works fine every single line of code there's nothing wrong except one logical thing.
When the form loads the RowValidating automatically fires because I have a function that Selects the table from the Database and it fills the DataSet by then attaching it to the datasourse of the "dgvTarifa" table. After setting the datasource of the datagridview, it automatically jumps to the RowValidating event which I DONT WANT TO! It first has to finish the whole function and later when the user enters with mouse or enters/leaves a row this has to be fired. (eventually already have the CellClick event with the same code below so only RowValidating has to work properly...)
Here's the code I use at row validating
Code:
Private Sub dgvTarifa_RowValidating(sender As System.Object, e As System.Windows.Forms.DataGridViewCellCancelEventArgs) Handles dgvTarifa.RowValidating
[Code].....
i have this code to open a record and this working if there is any, but if no records it will come out with error
[Code]...
I have a custom text box component (inherits from system.windows.forms.textbox) that I created in vb.net (2005) that handles the input of numeric data. It works well.
I would like to suppress the validating and validated events from firing if the number hasn't changed. If a user is tabbing through the form and tabs from the text box, the validating/validated events are fired.
I was thinking that the text box could cache the value and compare it to what is listed in the text property. If they are different, then I would want the validating/validate events to fire. If they are the same, nothing is fired.
I can't seem to figure out how to suppress the event. I have tried overriding the OnValidating event. That didn't work.
Update:
Here is the custom text box class. The idea is that I want to cache the value of the text box on the validate event. Once the value is cached, the next time the user tabs through the box, the validating event will check to see if the _Cache is different from the .Text. If so that is when I would like to raise the validating event to the parent form (as well as the validated event). If the _cache is the same, then I don't want to raise the event to the form. Essentially the text box will work the same as a regular text box except that the validating and validated method are only raised to the form when the text has changed.
Public Class CustomTextBox
#Region "Class Level Variables"
Private _FirstClickCompleted As Boolean = False 'used to indicate that all of the text should be highlighted when the user box is clicked - only when the control has had focus shifted to it
[Code]....
i have my form set to 50% of the working area of the Form's screen. I need to know when the screen's workingarea change and resize my form accordingly. Example: the user drags his windows taskbar and hence the workingarea reduces, and as such i wish to resize my form to 50% of the workingarea
View 3 RepliesI am working on a simple NES gaming reprogramming project (who doesn't try to program video games when they start out?) and am coming up with a goofy little error in my battle screen code. The Battle Screen is supposed to trigger and draw this form, but the thing redraws itself three or four times, creating an obvious and obnoxious triple-blink. Basically, the OnPaint event is still a bit of a mystery to me. Is there a way to reduce the amount of redraws so that it doesn't blink like it does?
Public Class Form1
Dim provider, dataFile, connString As String
Dim enemyTop, enemyLeft, enemyWidth, enemyHeight As Integer
[CODE]...
The program below works fine except for the problem for which The program below allows input of a volume and value which are both successfully drawn to the screen. I will be adding variables to retain the value of each new Volume and new Value input. However, I need code to delete the volume and value graphic numbers
drawn to screen when new volume and value's are input. At present new numbers are drawn on top of the existing graphics rather than replacing them. Every attempt to clear, draw over etc has failed. from a very grateful member about to go on holiday and I need this to work for use on hols.
The private sub resetting() does not work but I cannot see why.
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How do i run my current screen saver from VB2008 on the click event of a command button in my form?
View 1 RepliesBTW this issue occurs in any MS office program when the VB.Net (or even VBA) is processing information.Example: In Excel, a worksheet is displayed on the screen. I start either, a VB.Net or VBA procedure and within 30 seconds the Excel worksheet (previously displayed) blanks out. In both VB.Net and VBA,ScreenUpdating = False. My expectation is that the previously displayed screen would stay static as if I left my desk to get a cup of coffee; came back and the same ole Excel worksheet was still there?Of course, setting VBA Screen Updating = False accomplishes two goals: 1) speeds up processing and 2) saves the user from seeing unnecessary "garbage-processing" steps.Why does VBA or VB.Net ScreenUpdating = False not freeze the screen at the time of its invoking?
View 11 RepliesI've adapted the code from this link to use the WinXP on-screen keyboard (osk) for a touch-screen application written in VB.NET v3.5. The osk fills the bottom half of screen etc. and behaves fine except for one little quirk. If the user clicks or taps anywhere on the 'background' area behind/between the virtual keys (within the main osk window), the color of the area changes to that of the keys when any further key subsequently gets focus. The outline of all keys is then lost because they are visually merged into the osk window background. The osk must then be terminated and re-launched to remove the confusing appearance.
This behaviour only occurs when the osk window is set to the child style (i.e. when the menu is hidden), using the SetWindowLong P/Invoke function - e.g.
SetWindowLong(OskProcess.MainWindowHandle, GWL_STYLE, WS_CHILD)
It's as if the entire area behind the keys is being treated as another key when tapped/clicked, whereupon its color is 'restored' after losing focus.Is there any way to intercept and somehow override the focus event of this osk background area?
How do I make a splash screen with a progressbar that value changes base on the MainForm_load event? Example:When the mainform finished executing part of mainform_load, the progress bar in the splash screen changes to X value (eg 50)When mainform_load is executed completely, the progress bar moves to 100%, the splashscreen closes and mainform opens.
View 1 RepliesMy Application having MDI Form & many MDI Child form.When I open MDI child forms one by one from MenuStrip , I saw Flickering effect of fom?
Imports System
Imports System.Text
Imports System.Data.SQLite
Public Class frmMain
[code].....
I have read everything I can find, and understand some of it. I don't know what I am missing though. I can't get the flickering to stop. Can anyone help me? I've been using VB 2008 for months now, but I am new to the graphics bit. At first I tried using an ellipse from the powerpack, but that flickered even worse.
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I am working with GDI+ to draw backgrounds for my forms. I have a main form with 4 tabs, which all flicker. There is a gradient background behind them (bitmap drawn in GDI+ at Form_Load). I have double buffering enabled in the following manner:
Me.SetStyle(ControlStyles.UserPaint Or ControlStyles.AllPaintingInWmPaint Or ControlStyles.OptimizedDoubleBuffer Or ControlStyles.ResizeRedraw, True)
Everything on the form rarely flickers. The only times are when I am resizing, the numerous docked controls on my piece-o-junk netbook flicker momentarily, which is hardly noticeable. On a normal laptop it runs quite smoothly.The problem of which I speak is right on the headers of each tab (the white rectangle with text on it). When I move my cursor on or off of it, it will flicker. What is actually happening is that it is momentarily disappearing then re-appearing. This seems to be a control paint bug.I've tried the following override, without success.
Protected Overrides ReadOnly Property CreateParams() As System.Windows.Forms.CreateParams
Get
Dim cp As CreateParams = MyBase.CreateParams
[code]....
I have a combo box on a form, it has a large number of values in it (about 40000). When the combo box populates it flickers from invisible to visible for about a second.After investigating this I am sure that it is not the call to the database that is causing this but when the combo is drawn.
View 6 RepliesI am designing a Win Form in VB.NET and Using Table layout in it. Problem i facing is, My WimForm is flickering every time it is load.
Kindly suggest me permanent solution in VB.NET . Why this problem occurs ? Is it because of Table Layout ?
I have a form where i put controls at runtime. Everything works fine and fast. I also set the doublebuffer property of the controls to true and then there is no flickering at all. But then i proceed to add an image in the background (also during runtime), but then each item i move is flickering even if i remove all the controls and only leave the background image when i move another form it flickers anyway.I put an example below of how im adding the image.
Public originalImage As Image = Nothing
Private Sub Panel2_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Panel2.Paint
If originalImage IsNot Nothing Then
[code]....