VB.NET panel scrolling without showing scrollbars - vb.net

I am trying to create a custom UI element: a panel, derived from the original panel, which is scrollable with special scrollbars (not the integrated ones) and has some other special abilities.
The actual problem is the scrolling. When I change the value of the custom scrollbar (e.g. scrolling), the panel-integrated scrollbars show up suddenly, although autoScroll = false.
Leading to the unintended state where both scrollbars are visible, the integrated and my custom one.
Private Sub ScrollB_EvValueChanged(NewVal As Integer) Handles ScrollB.EvValueChanged
Me.CleanPanel1.VerticalScroll.Value = NewVal
End Sub
How can I assign the new scrolling position (the new offset), determined by the custom scrollbar, to the panel without showing up panel-integrated scrollbars?
Sadly a panel (or usercontrol) with another panel on it and playing with the .Top and .Left properties of the inner panel to simulate scrolling is not an appropriate solution in my case.
Thank you for all your hints!

'I've been looking for methods of doing this all over, most of it is way more complicated than it needs to be, or you gotta write a whole dang program just to remove the bars to scroll. Anyhow, here's a quick, effective, neat method of doing this (since I was having trouble finding anything, I'll post it.
'e.delta detects a mouse wheel tick, if greater than 0, scroll up, less than 0 scroll down.
' the -91 part deducts some of the panel overhang (adjust as needed)
'I have buttons in this project that are 50 tall, so this scrolls perfectly for me.
'the nested if statements where there is no code (just else), tells the program to stop 'do nothing if a border is near by. The bottom of my panel, while scrolling, doesn't 'stop when the bottom of the panel (which is hanging off the bottom of the form quite 'some ways) reaches the bottom of the form, this can be adjusted by altering the 700 constant.
Private Sub DaddyPanel_MouseWheel(sender As Object, e As MouseEventArgs) Handles DaddyPanel.MouseWheel
If e.Delta < 0 Then
If (-DaddyPanel.Height - 91) > (DaddyPanel.Location.Y - 700) Then
Else
TextBox1.Text = DaddyPanel.Height & " " & DaddyPanel.Location.Y
DaddyPanel.Location = DaddyPanel.Location + New Point(0, -50)
End If
Else
If DaddyPanel.Location = New Point(0, 0) Then
Else
DaddyPanel.Location = DaddyPanel.Location + New Point(0, 50)
End If
End If
End Sub

Related

Location properties on winforms acting strange

I have a form where I allow the user to generate multiple panels with some various contents in the panels by pressing an "add" button. Depending on what the user does in the panel, the panel grows and shrinks to fit the contents. Because of this change is size, I have created a sub that formats the panels on the form.
Private Sub formatPanels(frm As Form)
Dim count As Integer = 0
Dim startPoint As Point = New Point(12, 80)
Dim endPoint As Point = New Point(0, 0)
Dim maxY As Integer = 0
For Each pnl As Control In frm.Controls
If TypeOf pnl Is Panel Then
ReDim Preserve _arr_Panels(count)
_arr_Panels(count) = pnl
count += 1
pnl.Location = startPoint
startPoint.Y += pnl.Size.Height + 30
End If
Next
End Sub
So as you can see, we loop through every panel and the first always begins at the location (12,80) and then increments with the size of the panel and some spacing.
HERE IS THE ISSUE. This ONLY happens when i am SCROLLED DOWN the form. The panels spacing all of a sudden screws up and decides to put the first panel hundreds of pixels down the form. Is the location property based on what you're looking at? So if I were scrolled down the form location(0,0) would be the top left of the current view? There must be some weird property to location that I am not aware of.
Thanks
This behavior is not related to a panel, but to any control on a form with AutoScroll = True and Anchor including Top. (Note: if Anchor didn't also include Left I had some strange positioning on the first call of the function.
The solution is described here which is to use AutoScrollPosition. If you change your startPoint to this it will adjust for the scroll position.
Dim startPoint As Point = New Point(12, Me.AutoScrollPosition.Y + 80)
And the documentation for AutoScrollPosition states this:
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.

VB.NET - Change form size by screen resolution:

I'm presuming the answers very simple, but here's the issue, my option menu has two parts, normal settings and advanced settings, the advanced settings are accessed by pressing the advance button, fairly basic. This will make the form bigger unveiling the further settings, but the only problem I have is making a form bigger on different resolution does not make it bigger by the same factor - to put what i saying into context, if i increase the size of my form on a standard 1080p monitor, then run my program on a laptop resolution of 1366 by 768, the form will be much smaller than what i got it to draw on the 1080p resolution screen.
Heres the code I'm using to increase the form size:
Private Sub Advance_btn_Click(sender As Object, e As EventArgs) Handles Advance_btn.Click
If advanced = 0 Then
Me.Size = New Drawing.Size(262, 198) ' will increase form size
Advance_btn.Text = "<" ' text for button changes to know i have pressed the button - (to '<')
advanced = 1
ElseIf advanced = 1 Then
Me.Size = New Size(262, 85) ' will decrease form size
Advance_btn.Text = ">" ' text for button changes to know i have pressed the button - (to '>')
advanced = 0
End If
End Sub
The form is also without borders, if that makes somewhat a difference, thanks.
Me.Height = Screen.PrimaryScreen.Bounds.Height
Me.Width = Screen.PrimaryScreen.Bounds.Width * 0.6
In this example I use for years, the width is set to 60% of the screen width. This is in an IF statement, where I check if the user has a 4K monitor, if not, a full-screen mode is set at application start-up. You can, perpahs, do a similar thing with your drawing area.

Remove previous selection highlighting in RichTextBox without scrolling

I have a form with a RichTextBox (RTB) and a listBox.
When the end user selects an item in the listbox, any matched text in the RTB is highlighted (full code removed for brevity).
re = New Regex(txtToFind)
For Each m In re.Matches(rtbMain.Text)
rtbMain.[Select](m.Index, m.Length)
rtbMain.SelectionColor = Color.White
rtbMain.SelectionBackColor = System.Drawing.SystemColors.Highlight
Next
When the user left mouse clicks in the RTB I want the previously highlighted text to be cleared. This is the standard windows behaviour - If you manually select some text in an RTB with the mouse, it is highlighted, click anywhere back in the RTB and the highlighting disappears. My programatically selected text remains selected.
I have some partially working code (below). I can clear all the highlighted text, but it is by process of selecting everything, changing the colour back and then deselecting it again. I know it is not efficient, the RTB flickers and I am sure it is not the correct way to do it. Can I emulate the standard windows behaviour?
Also using my code, it scrolls to the first line when entering the RTB a second time.
I get around this the first time by returning the top visible line index before clearing the text and then selecting that line again afterwards and using ScrollToCaret(). This only works on the first pass. Subsequent MouseDown events select the top row regardless of where the user has clicked so nothing can be manually highlighted in the RTB.
Private Sub rtbMain_MouseDown(sender As Object, e As System.Windows.Forms.MouseEventArgs) Handles rtbMain.MouseDown
Dim topIndex As Integer = rtbMain.GetCharIndexFromPosition(New System.Drawing.Point(1, 1))
Dim topLine As Integer = rtbMain.GetLineFromCharIndex(topIndex)
If e.Button = Windows.Forms.MouseButtons.Right Then
'Do nothing (Context Menu)
Else
rtbMain.SelectAll()
rtbMain.SelectionColor = Color.Black
rtbMain.SelectionBackColor = Color.White
rtbMain.DeselectAll()
rtbMain.Select(topIndex, 0)
rtbMain.ScrollToCaret()
End If
End Sub
I need my code to emulate the standard windows behaviour - clear selected text highlighting on MouseDown and leave the mouse cursor where the user has clicked.
Any help anyone can offer is gratefully appreciated.
I think you may be overthinking this one.
In the right click event, try RtbMain.SelectionLength = 0

How to get Winforms Panel to correctly layout many items?

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

vb.net if 30px away from screen border

I have a resizable rectangle and also I have buttons that follow the bottom right side of it. But there is a problem, if the user re-sizes the box near the edge of the screen then the buttons will go off screen.
Although I've thought of a fix, and if the rectangle gets 32px close to the screens size then it moves the buttons [which will be above the line]. [Above the line is not the first option either].
I've tried using this code:
e.y, e.x = end of rectangle
If e.Y - 32 - = My.Computer.Screen.Bounds.Height Then
Label1.Text = "AboveLine"
Else
Label1.Text = "OutsideLine"
End If
At the moment I only want 'Label1.text' to change.. but it only works for that [32px] which is only 1px. Instead I want it to be like a boundary and if the rectangle size hits between 32px away from the edge of the screen and to the edge of the screen then it'll move the button by
Me.Button1.Location = New Point(e.X - 46, e.Y + 1)
Heres an example of what I mean
Image example
Hopefully someone can help. Thanks
I think this is what your after.
When the application is moved/dragged about, the 'Me.Move' event is fired
So what we are doing is checking the location of the right hand edge of the form, against the working area of the screen, the working area because that doesn't include the start bar, etc. And then the same with the bottom edge of the form
Private Sub Form1_Move(sender As Object, e As EventArgs) Handles Me.Move
If Me.Right > My.Computer.Screen.WorkingArea.Width - 32 Then
Label1.Text = "Too far right, move button"
End If
If Me.Bottom > My.Computer.Screen.WorkingArea.Height - 32 Then
Label1.Text = "Too far down, move button"
End If
End Sub
Use More than signs instaed of an '=', it works all the way to the edge and not just on the 32nd pixel