Access Picturebox From A Backgroundworker?
Jan 23, 2012
I have problem in my application to access a picturebox from a thread to make it visible or not.
When I try to change visibility from the thread, i get the above error, if i disabled crossthreading exception:
Me.CheckForIllegalCrossThreadCalls = False, the program run normally with no error but the image still not visible after i click the button (Start the thread and make picturebox1.visible = true)
change the visibilty of the picturebox from a thread (Backgroundworker).
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Sep 16, 2009
I am trying to access the checked state of a CheckBox from a BackGroundWorker thread. I am utilizing properties and it seemed to work just fine. However, I'm using 10-15 CheckBoxes and I think using the InvokeRequired property would probably be best. I've looked over JMC's thread that talks about how to access controls from the worker thread a bunch of different times and I can't seem to grasp the concepts. When it comes to the InvokeRequired property, I suppose I understand why it is needed. But I'm not sure if I understand it completely.
From the example that JMC provides:
vb.net
Private Sub ResetTextBoxText()
If Me.TextBox1.InvokeRequired Then
Me.TextBox1.Invoke(New MethodInvoker(AddressOf ResetTextBoxText))
Else
Me.TextBox1.ResetText()
End If
End Sub
If I'm not mistaken, this tells us that if invocation is required to access the control, then we access via the MethodInvoker if not, then we just access to directly? So, if I need to check the checked state of a check box, I know I can just put a conditional statement after the Else line if I can access it directly. But, if I can't how would I use MethodInvoker to check the checked state? And then, when calling it from the worker thread, would I just call the sub?
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Dec 14, 2009
in my button click event i ececure
If BackgroundWorker4.IsBusy Then
BackgroundWorker1.CancelAsync()
End If[code]....
after proceess completed if press the button again.i got the following error msg
This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.
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Aug 4, 2011
I'm working with BackgroundWorker, I want the BackgroundWorker do the retrieval process of data from database while the user can still do another task on the form. The problem is, after retrieving the data, I can't seem to access the ListView in my Form from the DoWork event of BackgroundWorker, I will populate that ListView using the data I've retrieved.
Consider this example, this is how I'm doing it:
Public Class Test
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code].....
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Dec 2, 2011
I am trying to get a access picture attachment to show in an vb.net picture box. At start up, I add an attachment field to the database, and add pictures to the database in jpg form. I then connect the database to vb project using the general vb settings. The connection is successful, I then add a picture box control to the form along with changing the attachment field to a picture box setting at this point every thing should be good. However, when I go to run the program the picture box remains empty.
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Aug 15, 2010
I'm trying to retrieve an image from my access database and insert it into a picturebox using the following code.
PictureBox.Image = rs.Fields().Item(8).Value
but it throws the following error
Quote: Unable to cast object of type 'System.Byte[]' to type 'System.Drawing.Image'
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May 2, 2011
I'm new in the vb.net world. The question I have is how to display an image which is in a access data base in a picturebox in visual basic(2010).
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Oct 18, 2010
I am trying to convert my DB field OLE Object as Bitmap into a Picture Box. In my DataBase there are 2 fields
1) Text
2) OLE Object (bitmap)
I am having problems trying to get the MS Access Database to equal the picture box. What I have so far is
Private Sub FindChemical()
Dim intDataBaseIndex As Integer
Dim rowIndex As Integer
Dim FieldRow As DataRow
[Code]....
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Jul 29, 2008
I have been working with Visual Basic 6 for over a year and have just recently to move up to .net. I have never had problems viewing picture boxes that were on one form thought another.My old code read something like:frm1.img1=frm3images.treeThis would take the image of the tree from a form that is not viable and place that image in the imagebox.
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Jun 8, 2011
In my project, it is desirable to access built-in color, dash styles, hatch styles by a numerical index rather than their names. For example, I would like to access the colors in a loop from 0 to 140 and display each of these in side by side rectangles in a picture box. Then later, when I click on the rectangle for a desired color, calculate the index of the color from the position of the rectangle in the picture box and use this index to set another object to the clicked color. I understand the coding for all of this except for how to get the colors from the enumeration in the loop and later, after I get the index from the clicked picture box, how to I access the desired color from the enumeration by using the index obtained from clicking the picture box.
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Mar 24, 2010
i am working a "image processing system" project in vb.net using the ms access2007.i have to browse by clicking a button and open a image to display its name to a text box and that image to picturebox.and after that i want to add,del and extract those images to the access database.i want to use datagridview control also.
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Mar 13, 2010
I have following code retrieving image from access database (OLE object)and assigning it to pic ctrl.
Dim bite() As Byte = CType(dg1.SelectedRows(0).DataGridView("subdivisionimage", dg.SelectedRows (0).Index).Value, Byte())
[Code].....
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May 10, 2012
I am programming with Access 2007 VB.net in Visual Studio 2010.I am trying to have my VB program read the database, extract the .bmp image, and assign it to a PictureBox on the fly (I am actually creating a Group on the fly and filling it with data from the database that are selected by my query. One of the fields is "image". All of my other fields are successfully transferring from the DB to the group box.) My problem is converting the OLE Object to a picture/image that I can assign to the PictureBox.I am using TableAdapters and queries set up in an .xsd.I have a database with an OLE Object field.Here is a code snipit of my database set up:
Dim ta AsNew dsWhiteboardTableAdapters.MonstersTableAdapter
Dim monsterList AsNewdsWhiteboard.MonstersDataTable
Dim monster AsdsWhiteboard.MonstersRow
[code]....
I have tried several ways of getting the image into my picturebox, all lead to errors.
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Apr 2, 2012
i'm in the need to start a backgroundworker inside another one.Now...The first one BGW starts a for cycle, and inside this one there is the second BGW that has to upload an image to a server.The trouble is that, the progress event and the complete event of the internal BGW are never called.
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Nov 24, 2011
I am trying to 1) write code in VB2010 that will get a JPG image from a Access Database field and write the image to a PictureBox 2) write code which will write a JPG file to an Access Database field. I have already sucessfully coded this in VB6, without fully understanding what I was doing.
Browsing the various forum's I have come across a few discussions on this subject, but due to my complete amerture status I don't seem to be able to follow the logic.
Below is the VB6 code
Writing JPG file to DataBase:
Dim bytBlob() As Byte
Dim intNum As Integer
[Code]....
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Feb 15, 2011
how to retrieve image from access database?.. I've just finish retrieving data to the datagrid view. I want to retrieve also the image (also stored in the database as path inside the table where the data stored) in the picturebox. When i clicked the specific data in datagrid view, it will show preferred image to picturebox.
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Jan 26, 2009
I have a form in vb.net 2005 with a datagrid and picturebox, when I click an item in the datagrid dgProducts I want to display the Picture which is stored in an access database in binary format inside the picturebox pbProduct. This is the code I have inside the datagrid click:
pbProduct.Image = Nothing
Dim x As Integer = dgProducts.CurrentRowIndex
Dim dt As DataTable
Dim drow As DataRow
[code]...
I have imported the system.io and system.data.oledb at class level and I hav generated this code from what I can find in forums online, but I get "Parameter is not valid" and no more help than that...
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Jan 27, 2010
when adding picture to dynamic picturebox from my.resources in .dll a duplicate semi functional picturebox is added too, behind the picturebox i intended to add. has anyone seen this happening before or can provide any insight into this?
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Jul 17, 2010
In VB6 I used some pattern of programming..I passed the picturebox as parameter to some procedure in some class and inside this procedure paint all needed graphics using this class methods.Now I want upgrade my application to vb.netBut all samples for line drawing show me how to draw inside paint event.[code]
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Mar 31, 2010
I have a PaintEventHandler connected to a picturebox via AddHandler.
In PaintEventHandler I have coded this for writing the drawing to PictureBox1.Image:
Dim PictureBox1 As PictureBox = CType(sender, PictureBox)
PictureBox1.Image = New Bitmap(PictureBox1.Width, PictureBox1.Height)
Dim bmp As Image = PictureBox1.Image
Dim g As Graphics = Graphics.FromImage(bmp)
... drawing something ...
PictureBox1.Image = bmp
Everything works fine but after running through the paint event handler and showing the picture on the screen it calls the painthandler again and again. It does not stop.
Replacing the code above with
Dim g As Graphics = e.Graphics
Makes it running. But then I cant save the Image to a file.
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Sep 27, 2009
I have a program I'm working on that, for one of the features, allows the user to drag an image from a picturebox, into the main form space, anywhere they want. [code]...
When trying to drag the image from the CurrentTilePicBox, the very moment I move the mouse while dragging the cursor becomes a circle with a cross and won't drag and drop into the new picturebox.
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Jan 14, 2010
Hey I am making a GDI++ game in vb.net. Now what I want is the monster(picturebox) to go after the player(picturebox). There Are No Vertical Walls. Only The Edge of map barriers. For example to get to the player the AI would have to go to the end of the ledge and either jump off and fall to the lower ledge or take the ladder down. There is no jumping, only falling and going up and down ladders and across the horizontal ledges. So How Can I make this pathfinding system?
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Feb 28, 2012
I have a panel, which contaisn two Pictures.When the panel is mousehover the Pictures appears. When the panel is mouseleave the Pictures disappears.However, when I'm trying to pass the mouse between the Picturebox and Panel, the Picturebox disappears, because the panel doesn't detect that as panel area.
Private Sub Panel_MouseHover(ByVal sender As Object, ByVal e As System.EventArgs) Handles Panel.MouseHover
Me.NextIMG.Visible = True
Me.PrevIMG.Visible = True
End Sub
Private Sub Panel_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles Panel.MouseLeave
Me.NextIMG.Visible = False
Me.PrevIMG.Visible = False
[code].....
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Feb 28, 2009
My app has scrolling images in the background and a picturebox on top. The image in the picturebox has transparent parts. How can It so that the transparent parts show whatever is belo the picture box, not the form background? I have tried taking screenshots and positioning them as background but this just freezes the app.
Dim ScreenSize As Size = New Size(154, 83)
Dim screenGrab As New Bitmap(154, 83)
Dim blank As New Bitmap(100, 300)
[CODE]...
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Jan 31, 2011
I need to plot some analog values read from the serial port.I plot them in a picturebox starting from left. When I reach the end of the control at the right side I shift all values to the left of a point and I plot the new point at the right, (I have some flickering but it could be acceptable). This is my plotting control.My problem is that I have to clear the control (picturebox) in order to plot the shifted graph, but the method Clear of the Graphics class clears everything inside the picturebox, even my grid.How can i make always visible a grid "in" my picturebox?
1.a transparent image with a grid over the PB? (the clear method cannot remove it)
2.an image with a grid below the picturebox that must be with a transparent background to make visible the grid?
3.multiple layers on the same picturebox?
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Feb 8, 2010
i'm doing a simple form tat could add picturebox during runtime and i could add several picture into it.
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Nov 11, 2009
Ok, so I have a new challenge for the D.I.C. Heads. I'm making a simple little game using VB controls. I know it's not the best idea in the world but it'll have to do for now!
Here is whats happening. I've created a class that inherits the PictureBox control that I want to use to place my game pieces on the playing field.
Dim pbArmyUnit(0) As ArmyUnit ' ArmyUnit is a Class that inherits Picturebox now I create the playing pieces at runtime as needed and append them to the array. Player currently buys the units and places them on the playing field.
[Code]...
On a side note how can I look at a stack of pictureboxes all created at runtime to determine whats at a particular location? Example. I move my army unit over top of the picturebox that shows my forest. How can I tell what picturebox I just moved on top of? does that make sense? I don't need code for this just directions on looking at the right info so I can figure it out.
I am creating my terrain at runtime as well since it's randomly generated. and I'm basically making an array of 192 pictureboxes with the appropriate terrain image as well as some other modifiers. Just like with my armies above I've inherited picturebox and created a terrain class array, this way I'm able to add my movement modifiers etc, directly to the picturebox I place on the screen. It's these pieces of terrain that I want to be able to check before allowing the unit to move into them! to get movement costs etc.
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Dec 4, 2011
how do i create an event for MouseEnter but instead of the mouse a picturebox?
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Jul 8, 2011
I have a picturebox on a form. The image in the picturebox is actually a report. I want it so if the user clicks on it it will zoom larger --- while the picturebox remains the same size. Of course, the entire image will no longer be seen. So I also want to be able to drap this image around with the cursor. The examples I've found for picturebox zooming cause the picturebox itself to get bigger and smaller. I need it to be like an Access report. Click on the report and it gets bigger. Click again and it goes back to the full image. Does anyone know of an example or tutorial in VB.Net for this type of zoom-with-fixed-size picturebox function?
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Jan 4, 2011
I am trying to draw a line on top of a picturebox but it keeps going behind the picturebox, even when I do Line.BringToFront()
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