How To Raise Paint Event Without Erasing Existing Graphics
Apr 2, 2009
This one is killing me. I don't think this would be so difficult if M$ documentation was to the point and talked in normal speak (I guess they don't understand KISS).it seems unnecessarily difficult to raise a paint event without a picturebox getting redrawn (all existing graphics erased). Invalidate, Refresh and Update all erase the picturebox. All I want to do is get the procedure ( with Handles Picturebox1.paint) to fire so I can draw to it without erasing what is already there. I looked into the RaiseEvent statement but there are a zillion errors that pop up for one reason or another telling me I can't do it. So: 1. How the heck can I get this to work? 2. Does anyone know of a great book on vb.NET that doesn't try to impress anyone with it's command of the English language, but instead teaches. As far as I can tell, M$ is full of themselves in a major way?
during the development of my project, i've the need to raise the paint event of a form, to make it with rounded angle.The strange thing is that, when i use the invalidate comand on it, the repaint event (that sometimes doesn't go and i don't know why), doesn't make it like i need, that is, the dimension of the side is one instead of six pixel, and the angle are rounded, but the border is not visible.
This is a working example which draws a rectangle on different location every timer_tick and I fully understand now how it's working:
Code: Dim i, timercount As Integer Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
[code]....
Now I'm looking for a way to draw this rectangles without refreshing them every single tick. I've just started using Visual Basic and I really don't know how to call/raise PictureBox1_Paint event every timer_tick or how to store drawing data in member variables?
I've got this code which draws a line and it moves down to a point then two curves are drawn coming off of it. I need to get it to repeat itself after a short period, so there's a constant flow of lines moving down then becoming curves.[code]
Running a graphics effect in the Paint event of a Form. I am thinking of something like a screensaver effect, not necessarily full-screen either. Would a background worker be better suited to this idea or using another thread? I wouldn't want something that is very demanding on a computer processor. In fact, what I was originally thinking, is it possible to put a Windows screensaver program inside a Form? Installing VB6 on Windows 7
I have tried to realign the image by down and right one pixel, but still only part of the first row and column are visible when zoomed.I can't find exactly what I'm looking for online.
My computer is an HP-Pavillion dv9600 Notebook PC.
OS: Windows Vista SP2 32-bit
The following code reproduces the problem:
Public Class PictureBug Dim pxlColor As Color Dim img As Bitmap = New System.Drawing.Bitmap(My.Resources.TestBug[code]......
I'm having a problem with the graphics portion of vb.net. As a school assignment, we are making "turtle graphics" applications. I have mine working perfectly, the problem that we are having (not even the teacher can fix it) is that when the window gets sent the command to be painted (ie minimized and maximized) the drawings in the picturebox I am using are completely erased. I am looking for a way to prevent this from happening. I have been trying to store the image as a bitmap in memory, which does not work. Is there another way to draw to a bitmap/image in memory and then output that to a picturebox?
i guess the title pretty much states the question but i will give the senario to be more clear. i have a mousemove() event which i add in my program programmatically and i need a way for raising that event (again) programmatically too. raiseEvent control_mousemove() doesn't work as it says that "'control_MouseDown' is not an event of 'main'."
What language is the best if you want to make a large paint program (such as photoshop)? And how can I paint the best way, so I have much possibillities?
I want to raise an event for an opto-input state change but not sure if I can. Basically I have 4 opto-inputs on a PCI control card - one of which changes pretty rapidly - that I currently poll with a timer. I'm looking at getting a proper hardware counter for that but the other 3 are production status indicators. I'd prefer it if they alerted the app to a state change though.
Depending on the state of one of the inputs I have to fire a relay which simulates a button push. Having been playing with serial ports and getting a very useful app built for logging production data into a SQL Server DB I want to re-visit a proof-of-concept system I built a few months ago.
Current code - which works fine - but I'd like to change is like this:
Private Sub tmrOptoInput_0_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrOptoInput_0.Tick 'Read OptoInput_1 to Monitor Track State... Dim aType As Byte ' replace Byte with any other type
[code].....
Having 4 inputs so I need 4 timers, plus another one that polls the database and checks a status flag which triggers the app to start logging. I'd like it to be event driven rather than timer driven if at all possible but I don't know how and there's nothing in the control card docs. Also I can't seem to find anything relevant on the web.
This little experiment was a test prompted by a previous thread to learn to work in a graphics object, then paint everything later to a picturebox (later, will be looking at building own custom control for the display), and save out the bitmap to a file on the HD.But weird things happen here. Nothing will display in the picturebox, and the saved bitmap is just a black box.The only partial success I had was replacing: e.Graphics.DrawImage(MyBitmap, 0, 0)
with, PictureBox1.image = MyBitmap
inside the paint event handler, but that caused infinite recursion of the paint event. But at least I could see parts of the graphic for a fraction of a second before it was wiped clean, every time I clicked the "Go_cmd" button. But what is weird is that this partial success showed that the graphics object was copying successfully over to the bitmap image (because I could briefly see parts of it in the picturebox, but the saved file would still come out black, even though it was based on the same bitmap!The code is as follows.Above the form1 class
Imports System.Drawing.Imaging The single declaration:
Public MyBitmap As Bitmap The form_load procedure:[ code].....
The code in the version shown above would not even show a brief moment of the graphics in the picturebox, and the saved .bmp file is just a filled black box.
I've got a basic idea of what i'm wanting to do, just been out of it too long to remember how to do it. I'm wanting to load an image, not display it. Get all the pixel data, then redraw the image pixel for pixel in mspaint.
How can I cause the Paint event to fire from a Form_Click() event? This is what I'm trying to do...
Public Class StrTests01 Private Sub StrTests01_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Click Dim ps As Graphics = Me.CreateGraphics()
Is it possible to run a sub routine on my form after all other sub routines have finished? I am having a problem using a filewatcher that watches a certain path and runs an SQL job if a certain file is pasted. For some reason my procedure leaves a file behind sometimes and others it does not. I was wondering can I use a form event to run a different procedure after all other sub routines on the form are completed that would check this directory for remaining files again?
I have a button that I need to use twice, the first time I click it, it validates that a string inside a textbox is a certain length. That part works. What I want to do is press the same button again but when I press it the second time it is suppose to popup a hidden label. But when I try to use a raiseevent command it gives me an error saying "the button is not an event in my program" tell me how to use the OnClick?
I have an MDI parent form and 2 child forms. Each child form has data bound controls bound to the same sql table; one from is for displaying data and the other is for editing data. After the editing form closes, I need to update the data in the display form (if it is displayed). I can think of a few ways to do this, but I would like the display form to simply respond to an event raised by the database. Is it possible to create (and raise) an event in the database proper? If not what is the best/acceptable way to update data on a data bound form?
I have 2 classes one main class called Mygrid and another class inside it called TLBoxEditingControl which inherits a textbox into grid cell.Also I have added one Listbox called LstBox to the usercontrol MyGrid.
1) Initially its visible is false. How can i make visible true in TLBoxEditingControl class.
2) I have an Event called MyList() in Main Class, how can I raise this event in TLBoxEditingControl class.
Here is the code i use, This is not working please expalin
Public Class MyGrid Inherits DataGridView Public Event MyList()
[code]....
I have added this control to a form and added this code
Private Sub MyGrid1_MyList() Handles MyGrid1.MyList MsgBox("ggg") End Sub
Private WithEvents newMessages As New List(Of NewMessageList) Private Sub VariableChanged(ByVal NewValue As Integer) Handles newMessages.listChanged MessageBox.Show(CStr(newMessages.Count))
[code]....
This part is the issue: newMessages.listChanged because the even can not be found. What am I missing?
I converted some code from c# to vb, I have the following error:-
m_axCalendar.DoRetrieveDayEvents += New AxXtremeCalendarControl._DCalendarControlEvents_DoRetrieveDayEventsEventHandler(m_axCalendar_DoRetrieveDayEvents) Red Error = Error1'Public Event DoRetrieveDayEvents(sender As Object, e As AxXtremeCalendarControl._DCalendarControlEvents_DoRetrieveDayEventsEvent)' is an event, and cannot be called directly. Use a
[code]....
I can get rid of Blue error by changing it to : AddressOf m_axCalendar_DoRetrieveDayEvents Not sure how to fix red error?
