I'm trying to make a few images do the nice slidey thingy that I've seen lots of Microsoft applications use. The one where the movement starts slow speeds up half way there and then comes to a nice slow stop in it's new location. I've got all the calculations figured out, getting and setting the picture box locations, Confirmation using console.writeline that the image locations are correct, and even a test run that works in a simplified format.
But in the full blown version It's not repainting the image. In fact, it looks like nothing has happened at all while the script is running. I've tried Me.Refresh(), Invalidate(), Timer.Enabled = True/False, and Me.Update(). None of which have worked. The last step is the most frustrating: I'm calling my SetPanelLocation() method at the end to ensure that the panel ends up in the final location regardless of if the movement worked. Nothing happens on this call either, even though immediately after this routine fails I can call the same method from another user event and it starts working again like nothing was wrong.
I'm creating my own PictureBox class called clsFeedImageBox which inherits PictureBox that includes this functionality (along with other features). Each image is only 300x225 pixels so they're not massive images that take a lot of time to redraw. Each instance of this class is in a common Forms.SplitterPanel. I use a lot of comments out of habit so i left them in here, maybe they'll add some light.
Public Class clsFeedImgBox
Inherits PictureBox
Private iRank As Integer 'rank in whatever feed this file gets put in
Private iRankTarget As Integer 'rank to move to when rank feed event starts
Private iTopStart As Integer 'starting top location before feed event
Private iTopTarget As Integer 'final Top location after feed event
Private WithEvents tMyTimer As New System.Timers.Timer
Private WithEvents oParent As FeedBase 'splitter panel, all location info comes from the parent
Public Sub New(ByRef sender As FeedBase, ByVal rank as Integer)
'set objects
oParent = sender
'set .Image property to pre-made thumbnail
Image.FromFile(ThumbPath) 'ThumbPath is a property which is set by this point (some code has been removed)
'setup initial position
setPanelLocation(rank)
'set autosize
Me.SizeMode = PictureBoxSizeMode.StretchImage
'set Image Scroll timer interval to 20 fps (1000 / 20 = 50)
tMyTimer.Interval = 50
End Sub
Public Sub scroll(ByVal newRank As Integer)
'setPanelLocation(newRank) <== this works, timed movements don't
iRankTarget = newRank
iTopStart = Me.Top
iTopTarget = oParent.ImgTop(newRank) 'gets an integer for the new Top location
tMyTimer.Start()
End Sub
Private Sub myScrollStep() Handles tMyTimer.Elapsed
'tMyTimer.Enabled = False 'this idea with the enabled = True at the end didn't work
iTickCount += 1
Dim iScrollPerc As Integer 'scroll % between Start and End * 100
iScrollPerc = oParent.ScrollStep(iTickCount, Rank) 'this part works
Console.WriteLine(strThumbName & " scrollPerc: " & iScrollPerc.ToString)
If iScrollPerc >= 100 Then
'scroll event complete
Console.WriteLine(strThumbName & " SetFinalLocation")
Me.setPanelLocation(iRankTarget) '<== This line doesn't work here, but works when called by other means
'stop Feed updates
tMyTimer.Stop()
'reset iTickCount for next movement
iTickCount = 0
Else
'scrolling still going
Dim newTop As Integer
newTop = Math.Round(iTopTarget - (((100 - iScrollPerc) * (iTopTarget - iTopStart)) / 100)) 'this part works
'Console.WriteLine(strThumbName & " TopTarget: " & newTop)
Me.Top = newTop 'Nothing happens here
End If
'Me.Left = oParent.ImgLeft
'Me.Width = oParent.ImgWidth
'Me.Height = oParent.ImgHeight 'that didn't work
'Me.Refresh() 'this didn't work
'Invalidate() 'this didn't do much good either
'Me.Update() 'Aaaaand no cigar, time for StackOverflow
'tMyTimer.Enabled = True
End Sub
Public Sub setPanelLocation(ByVal rank As Integer)
iRank = rank
Me.MyRePaint()
End Sub
Public Sub MyRePaint()
'repaint image box with everything in it's current rank
Me.Left = oParent.ImgLeft
Me.Top = oParent.ImgTop(iRank)
Me.Width = oParent.ImgWidth
Me.Height = oParent.ImgHeight
End Sub
End Class
What gives? There must be some inner workings of VB.NET that will help me figure this out. I'm using VS 2012 and Win8
You could make a WPF application and use a Slider control instead of "manually" making a slider with planes, picture boxes, etc, etc.
Related
I'm trying to code it so that i can create a picture box from a method in a class. However when my picture box is drawn it doesn't display any image, it only shows a white square of the specified dimensions in the specified location.
Here is the code which i am using to create said picture box:
Public Sub DrawEnemy(ByRef formInstance)
Dim enemypic As New PictureBox
enemypic.Image = Image.FromFile("C:\fboi1\Enemy.Png")
enemypic.Width = 64
enemypic.Height = 64
enemypic.Location = New Point(Me.EnemyPosX, EnemyPosY)
enemypic.Visible = True
formInstance.Controls.Add(enemypic)
End Sub
And here is where i am calling the method from:
Dim Enemy1 As New computerControlled(1, 1)
Enemy1.DrawEnemy(Me)
Please add the following code in your DrawEnemy() method:
enemypic.SizeMode = PictureBoxSizeMode.StretchImage
When i drag the console window suddenly the white box turns into the image i wanted.
Aha! This means the code is not causing the form to be repainted. We can trigger that by calling the Invalidate() function.
Public Sub DrawEnemy(formInstance As Form)
Dim enemypic As New PictureBox
enemypic.Image = Image.FromFile("C:\fboi1\Enemy.Png")
enemypic.Width = 64
enemypic.Height = 64
enemypic.Location = New Point(Me.EnemyPosX, EnemyPosY)
enemypic.Visible = True
formInstance.Controls.Add(enemypic)
formInstance.Invalidate()
End Sub
If you're calling this several times in a loop, you would instead handle this after the loop, where you also block repainting (to prevent flickering) until the loop is finished.
form.SuspendLayout()
For Each enemy In ...
'...
DrawEnemy(form)
Next
form.Invalidate()
form.ResumeLayout()
It's also possible you only need to Invalidate() the picturebox.
I'm running the following loop successfully when the number of items is low. However, when run against a larger list on the ListView, it seems to be taking way too long. I tested it with a list of 8,700 files and it took about two hours to complete. Is there something I can do to speed this up? I guess that removing the check for the Cancel button would help but I would like to keep that there for usability. As I've mentioned in earlier posts, I'm pretty new to Visual Basic so please provide lots of explanation with your suggestions. Thanks. Here's the code:
For i As Integer = 0 To m_CountTo
' Has the background worker be told to stop?
If BackgroundWorker1.CancellationPending Then
' Set Cancel to True
e.Cancel = True
Exit For
End If
'Select the row from the LVFiles ListView, then move the first column (0) into strSourceFilePath and the last
' column (3) into strDestFilePath. Execute the CopyFile method to copy the file.
LVFiles.Items(i).Selected = True
strSourceFilePath = LVFiles.SelectedItems(i).SubItems(0).Text
strDestFilePath = LVFiles.SelectedItems(i).SubItems(3).Text
My.Computer.FileSystem.CopyFile(strSourceFilePath, strDestFilePath, overwrite:=False)
' Report The progress of the Background Worker.
BackgroundWorker1.ReportProgress(CInt((i / m_CountTo) * 100))
' Me.LabelStatus.Text = FormatPercent((i + 1) / (intLVIndex + 1), 2) ' Show Percentage in Label
SetLabelText_ThreadSafe(Me.LabelStatus, FormatPercent(i / m_CountTo, 2))
Next
The Backgroundworker encapsulates a new thread. You cannot directly access controls that are created in another thread. If you do you will get an InvalidOperationException because of a cross-thread operation. The Backgroundworker however offers some functionality to share data (or access to controls) between threads. You should use them.
Private Sub StartBGW_Click(sender As Object, e As EventArgs) Handles StartBGW.Click
Dim dict As New Dictionary(Of String, String)
For i As Integer = 0 To m_CountTo
dict.Add(Me.LVFiles.Items(i).SubItems(0).Text,
Me.LVFiles.Items(i).SubItems(3).Text)
Next
Me.BackgroundWorker1.RunWorkerAsync(dict)
End Sub
First we prepare a dictionary that contains the source as Key and the target as Value. This object is given to the BackgroundWorker as a parameter.
Now comes the essential part:
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim counter As Integer = -1
Dim dict = DirectCast(e.Argument, Dictionary(Of String, String))
For Each kvp In dict
counter += 1
' Has the background worker be told to stop?
If Me.BackgroundWorker1.CancellationPending Then
' Set Cancel to True
e.Cancel = True
Exit For
End If
'Select the row from the LVFiles ListView, then move the first column (0) into strSourceFilePath and the last
' column (3) into strDestFilePath. Execute the CopyFile method to copy the file.
My.Computer.FileSystem.CopyFile(kvp.Key, kvp.Value, overwrite:=False)
' Report The progress of the Background Worker.
Me.BackgroundWorker1.ReportProgress(CInt((counter / m_CountTo) * 100), counter)
Next
End Sub
We don't access the ListView anymore. Instead we use the dictionary that is given to us as a parameter through e.Argument. Theres also a slight difference in the BackgroundWorker1.ReportsProgress line. There's a second parameter I have used to pass the current index to the ProgressChanged event which can be obtained via e.UserState.
Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
Me.LVFiles.Items(Convert.ToInt32(e.UserState)).Selected = True
Me.LabelStatus.Text = e.ProgressPercentage.ToString
End Sub
This event is designed to be raised with a SynchronizationContext of the calling thread, in this case the UI thread. Here we can safely access any control and update them. The index is passed as e.UserState, so we can access the relevant item and set their Selected property to true.
The biggest improvement comes from the change of Me.LVFiles.SelectedItems(i).SubItems(0).Text to Me.LVFiles.Items(i).SubItems(0).Text. I'm not a professional, but it seems that SelectedItems isn't a real list. Instead it iterates through every item using the SendMessage API until the desired index is reached. This is why it takes longer the higher your index is. Everytime it starts with the first item and iterates through them. Lot of operations.
The second improvement is the separation of code that access UI controls. It's all done in one method now. More clear and readable.
Update: #Enigmativity mentioned that SelectedListViewItemCollection implements IList and therefore is a real list. Even though it has no underlying list containing all selected items like you have in ListViewItemCollection. My point was to say, that accessing a single element is more complicated.
I'm working on a VSTO add-in for Excel 2013 in VB.NET that will help me interface with an instrument via a serial connection. I currently have the COM connection set up correctly and it will allow me to send and receive one command at a time. I'd like to set it up so that I can push one button and have it collect two separate readings in different worksheet cells. Using the code below, the tools work great to collect a single reading, but when I enable the code to send a second command to the instrument the Data Received event stops working entirely until I send another single read command. I know that the instrument received and processed the second command, but it never appears in excel. Could anyone help with a way to modify this code?
Private Sub mySerialPort_DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
'Handles serial port data received events
UpdateFormDeligate1 = New UpdateFormDeligate(AddressOf UpdateDisplay)
Dim n As Integer = mySerialPort.BytesToRead 'find number of bytes in buff
comBuffer = New Byte(n - 1) {} 're-dimension storage buffer (n - 1)
mySerialPort.Read(comBuffer, 0, n) 'read data from the buffer
comBuffer2 = mySerialPort.ReadTo(vbCr)
Me.Invoke(UpdateFormDeligate1) 'call the deligate
mySerialPort.Close()
End Sub
Private Sub Invoke(updateFormDeligate1 As UpdateFormDeligate)
lblReading.Label = processReading() 'write to a Current Reading lable on the ribbon
Dim myApp As Excel.Application = Globals.ThisAddIn.Application
Dim currentCell = myApp.ActiveCell
currentCell.Value = processReading() 'write data in the excel active cell
Try
advanceCell()
Catch ex As Exception
System.Windows.Forms.MessageBox.Show(ex.Message)
End Try
If measureNo = 2 Then 'this case is selected when I want to read 2 measurements with a single button push
cmdSent = 2
sendCommand(measureCmd)
End If
End Sub
Private Sub UpdateDisplay()
End Sub
Note that I did not include my sendCommand sub because this is a simple .write command to the instrument that appears to be working correctly in all cases. I'd much appreciate any help anyone could provide as I'm pretty new to using data received events.
OK, I tried to isolate only the relevant the part of the script that was having an issue and I created a completely new toolbar for testing. Below is the full code for this new toolbar that contains one connect/measure button and a label that displays the status/result. I tried to comment the code to make it readable, hopefully this helps.
This new toolbar does appear to be working correctly. I'm still a little unsure on my correct usage of the DataReceived event handler in conjunction with the Invoke method (which Visual Studio slightly changed for use with Excel2013). Could anyone please provide comment as to whether I'm still using these events in an unclear way and provide a suggestion on how I may make it better?
Thanks again in advance for any help. I really appreciate it.
Imports Microsoft.Office.Tools.Ribbon
Imports System.IO.Ports
Public Class Measure2x_COM
Dim mySerialPort As New SerialPort
Dim CMD As String = "M" & vbCr 'statement telling instrument to measure
Dim measureNo As Integer = 0 'counts the number of measure commands sent to the instrument
Private Delegate Sub UpdateFormDeligate()
Private UpdateFormDeligate1 As UpdateFormDeligate
Dim sngReading As Single 'this is the reading received from the instrument as a single data type
Private Sub setupConnectCOM()
'Open COM and send measure command - this part works correctly
'first, check if serial port is open
If mySerialPort.IsOpen Then 'send measure command
mySerialPort.Write(CMD) 'the instrument will generally take 15.1 sec to perform a measurement before sending the result back
Else
'if serial port is not open, set it up, then open, then send command
'Setup COM --this part works correctly
With mySerialPort
.PortName = "COM3"
.BaudRate = 1200
.DataBits = 7
.Parity = Parity.None
.StopBits = StopBits.Two
.Handshake = Handshake.None
.ReadTimeout = 16000
End With
Try
mySerialPort.Open()
Catch ex As Exception
System.Windows.Forms.MessageBox.Show(ex.Message)
Exit Sub 'exit sub if the connection fails
End Try
Threading.Thread.Sleep(200) 'wait 0.2 sec for port to open
mySerialPort.Write(CMD) 'send measure command after serial port is open
End If
measureNo = 1
lblResult.Label = "Measuring"
End Sub
Private Sub Measure2x_COM_Load(ByVal sender As System.Object, ByVal e As RibbonUIEventArgs) Handles MyBase.Load
AddHandler mySerialPort.DataReceived, AddressOf mySerialPort_DataReceived
End Sub
Private Sub mySerialPort_DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
'Handles serial port data received events
UpdateFormDeligate1 = New UpdateFormDeligate(AddressOf UpdateDisplay)
'Read data as it comes back from serial port
'I had to do this in two steps because it, for some reason needs to read
'the +/- symbol as a Byte, then needs to read the ASCII measurement number
'the third part concatenates the data and converts it to a single type
'part 1 - read +/- symbol
Dim comBuffer As Byte()
Dim n As Integer = mySerialPort.BytesToRead 'find number of bytes in buff
comBuffer = New Byte(n - 1) {} 're-dimension storage buffer (n - 1)
mySerialPort.Read(comBuffer, 0, n) 'read data from the buffer
'part 2 - read ASCII measurement number
Dim comBuffer2 As String
comBuffer2 = mySerialPort.ReadTo(vbCr)
'part 3 - concatenate read data and convert to single type
Dim txtReading As String = Nothing
txtReading = System.Text.ASCIIEncoding.ASCII.GetString(comBuffer) & CStr(CInt(comBuffer2) / 10)
sngReading = CSng(txtReading)
'Call the update form deligate
'Visual Studio slightly changed this from the example on Microsoft's website that used a Windows Form
'I tried the code in a windows form and I get the same results
Me.Invoke(UpdateFormDeligate1) 'call the deligate
End Sub
Private Sub Invoke(updateFormDeligate1 As UpdateFormDeligate)
lblResult.Label = sngReading 'set the Result label in the ribbon to equal the received data value
'now place the data received in the active cell in the worksheet
Dim myApp As Excel.Application = Globals.ThisAddIn.Application
Dim currentCell = myApp.ActiveCell
currentCell.Value = sngReading
'advance cell to the next cell
Dim newCell = currentCell
newCell = myApp.ActiveCell.Offset(1, 0)
newCell.Select()
currentCell = newCell
'check if this was the first reading from the instrument
'if it was the first reading, then send a second read command
If measureNo = 1 Then
measureNo = 2 'make sure to change measurement number to 2 to avoid infinite loop
mySerialPort.Write(CMD) 'send command to measure to instrument
End If
End Sub
'the usage of this section changed from the Microsoft Windows Form example
'in function, the mySerialPort_DataREceived(), Invoke(), and UpdateDisplay() functions do appear to be
'working with the same results and same hangups
Private Sub UpdateDisplay()
End Sub
Private Sub btnMeasure_Click(sender As Object, e As RibbonControlEventArgs) Handles btnMeasure.Click
setupConnectCOM() 'connect to COM and send first measure command
End Sub
End Class
I have a VB.NET winforms application. One of its forms, contains a flowlayoutpanel which I populate dynamically (programmatically) on form load event with pairs of label-textbox. My flowlayoutpanel is created in design time with all the properties set to default except below ones:
AutoSize: true
AutoScroll: true
Dock: fill
FlowDirection: TopDown
Then I populate it using below code within the form load event:
Private Sub MyForm_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Handles Me.Load
Dim lbl As Label
Dim txt As TextBox
Dim flowLayout As FlowLayoutPanel
Dim g As Graphics
For i As Integer = 0 To 253
lbl = New Label
lbl.Text = i.ToString("000") + ":"
lbl.Anchor = AnchorStyles.None
lbl.AutoSize = True
txt = New TextBox
txt.Text = "<" + i.ToString.PadLeft(3, " ") + ">"
txt.MaxLength = 5
txt.Anchor = AnchorStyles.None
txt.ReadOnly = True
g = txt.CreateGraphics
txt.Width = g.MeasureString(txt.Text, txt.Font).Width + 5
g.Dispose()
flowLayout = New FlowLayoutPanel
flowLayout.FlowDirection = FlowDirection.LeftToRight
flowLayout.AutoSize = True
flowLayout.Anchor = AnchorStyles.None
flowLayout.Margin = New Padding(0)
flowLayout.Padding = New Padding(0)
flowLayout.Controls.Add(lbl)
flowLayout.Controls.Add(txt)
Me.FlowLayoutPnl.Controls.Add(flowLayout)
Next
End Sub
As I have stated above FlowLayoutPnl is created on design time and components on this are added following TopDown flow direction.
Above code produces this result.
The problem here is that on opening this form it takes so much time (a few seconds) to open because it is doing all the stuff in form load event. It takes 35 seconds to open!. When all the stuff is done then form becomes visible after 35 seconds...
So I would like to know if there is some kind of method to speed up form load. I have read some posts here saying about implement and show some kind of splash screen while it loads indicating user that it is being loaded or even perform an asynchronous load. What about creating a background thread from form load event in order to do this stuff? Anyone could guide me in the right direction? A very little example will be highly appreciated. How this kind of problems are normally resolved?
I've got a WinForms Panel control which holds a large number of child controls. Each child is left docked, causing the horizontal width of the contents to grow. The containing Panel has its AutoScroll property set so that you can get to all the contents.
I'm running into a problem when the total width of the contents gets too large. Once you've hit this maximum width, additional content elements are placed on top of existing contents instead of being placed to the right. But, if I resize the Panel after it has done its initial layout, it corrects itself by expanding its logical width and placing each content element in the correct location. How do I get it to layout correctly before the user resizes the window?
Here's a simple example:
Form1.vb
Public Class Form1
Protected Overrides Sub OnLoad(e As EventArgs)
MyBase.OnLoad(e)
For i As Integer = 1 To 200
Dim gb As New GroupBox
gb.Text = "Box " & i.ToString
gb.Width = 250
gb.Dock = DockStyle.Left
Panel1.Controls.Add(gb)
gb.BringToFront()
Next
End Sub
End Class
Form1.Designer.vb
Partial Class Form1
Inherits System.Windows.Forms.Form
Private Sub InitializeComponent()
Me.Panel1 = New System.Windows.Forms.Panel()
Me.SuspendLayout()
'
'Panel1
'
Me.Panel1.AutoScroll = True
Me.Panel1.Dock = System.Windows.Forms.DockStyle.Fill
Me.Panel1.Location = New System.Drawing.Point(0, 0)
Me.Panel1.Name = "Panel1"
Me.Panel1.Size = New System.Drawing.Size(284, 262)
Me.Panel1.TabIndex = 0
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(284, 262)
Me.Controls.Add(Me.Panel1)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
End Sub
Friend WithEvents Panel1 As System.Windows.Forms.Panel
End Class
This is what the window looks like when it first comes up, scrolled nearly to the end so you can see the problem area. Notice that Box 183 to 199 are missing because they are placed on top of each other. This is not right.
This is what the window looks like after you manually resize it, scrolled nearly to the end. The panel fixed itself in response to the resize; the total logical width of the panel was automatically extended enough to hold all the contents. This is what I want it to look like when it first comes up.
I've tried manually setting the location of each box, and I've tried calling PerformLayout() and several other functions. Nothing seems to work. So far I haven't found the magic combination to get the good layout. Does anyone know how to fix this?
Edit:
Here's a screenshot that might make the issue more obvious. I adjusted the box widths and the number of boxes to show the problem better. See how the last box overlaps box 656? Every box from 657 to 700 has the same incorrect location. Turning off docking and setting the location myself doesn't help.
Looks like a bug with the scrolling information. If you call PerformLayout when the Panel is scrolled all the way to the right, it correctly places the controls in the proper place. That requires some code in the OnShown method:
Protected Overrides Sub OnLoad(e As EventArgs)
MyBase.OnLoad(e)
Panel1.AutoScroll = True
Panel1.SuspendLayout()
For i As Integer = 1 To 200
Dim gb As New GroupBox
gb.Text = "Box " & i.ToString
gb.Width = 250
gb.Dock = DockStyle.Left
Panel1.Controls.Add(gb)
gb.BringToFront()
Next
Panel1.ResumeLayout(False)
End Sub
Protected Overrides Sub OnShown(e As EventArgs)
MyBase.OnShown(e)
Panel1.AutoScrollPosition = New Point(Panel1.HorizontalScroll.Maximum - _
Panel1.HorizontalScroll.LargeChange, 0)
Panel1.PerformLayout()
Panel1.AutoScrollPosition = Point.Empty
End Sub
Of course, having over 200 container controls on the form is never recommended.
AutoScroll is not AutoPositionMyChildren. From MSDN:
When adding controls programmatically to a form, use the AutoScrollPosition property to position the control either inside or outside of the current viewable scroll area.
If you looped thru the controls, to print their location, you's see at some point (probably around 130) that Location.Y becomes fixed at 32767 probably some default unscrolled max. This is also the point they start stacking because they in fact have the same initial location. Some of the code you have makes up for that but it isnt quite right. Once you scroll it, the panel fixes the coords on the child controls.
First, I would suggest that you set Panel1.AutoScrollMinSize to something like {480, 0} so that the HScroll bar appears at design time; this allows you to calc a good height for the boxes which wont cause a VScroll as you add controls.
Dim gb As GroupBox
' only 150 because problem is when (i * width) > 32k
For i As Integer = 0 To 150
gb = New GroupBox
gb.Name = i.ToString ' added
gb.Text = "Box " & i.ToString
gb.Width = 250
' no docking so set the height
gb.Height = Panel1.Bounds.Height - 30 ' trying to avoid the VSCroll
' set location explicitly
gb.Location = NewCtlLocation(Panel1.Controls.Count,
Panel1.AutoScrollPosition.X)
' Dock and Anchor mess up the AutoScroll
'gb.Dock = DockStyle.Left
Panel1.Controls.Add(gb)
' allow panel to update its scroll positions
Panel1.ScrollControlIntoView(gb)
' not needed; seems to offset something with Dock
' changing ZOrder may not always be desirable
'gb.BringToFront()
' debug illumination
Console.WriteLine("{0} {1} {2}", i.ToString,
Panel1.AutoScrollPosition.X.ToString,
gb.Location.X.ToString)
Next
'Go back to start
Panel1.ScrollControlIntoView(Panel1.Controls("0"))
Location helper so you can tweak gutters or margins (dock replacement):
Friend Function NewCtlLocation(ByVal n As Integer,
ByVal ScrollPosX As Integer) As Point
Const TopMargin As Integer = 5
Const LeftMargin As Integer = 5
Return New Point((n * 250) + ScrollPosX, 0)
End Function
Notes:
I have a vertical scroller which repeatedly adds up to 120 user controls which works well but it does not need/use ScrollControlIntoView and they never stack up like yours do. I suspect maybe because they are smaller. There is also at least a second or two before the next one can be added, which may matter. But, good to know.
It might be possible to use the ControlAdded event of the panel to do something, but it would likely amount to ScrollControlIntoView. Doing it once at the end only doesnt work, so using it as they are added is allowing something to get updated as you go.
With the right fiddling, you might be able to get Dock to work, but I suspect it may be part of the problem such as Height and Left set this way dont update the panel's internal scroll map.
Your boxes actually look narrower than 250 - is autosize on?
Suspend/Resume Layout hurt rather than help - they prevent the control from doing anything about the virtual area being populated. It should happen fast enough that no one will see anything. Results:
Works on My SystemTM