Center on object always

Question

How do I force the screen to always center on a picture box or object?

Answer 1

Do you mean you always want your form centered in the screen? I am unsure of what you mean.

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You've taught me everything I know but not everything you know.

Answer 2

Be aware that this is sometimes done by some websites (card games and sex) who force their part in the middle of the screen over all other data.

That is not liked by most users and can therefore be seen as usable for malicious intent.

 

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Success
Cor

Answer 3

I have a sample code were its done kinda using the mouse event

Private _GridSize As Size
    Private _GridOrigin As Point
    Private _CellSize As Size = New Size(100, 100)
    Private _ClickDelta As Point
    Public Sub New()
        ' This call is required by the designer.
        InitializeComponent()
        ' Add any initialization after the InitializeComponent() call.
        DoubleBuffered = True
        Me.ClientSize = New Size(600, 600)
    End Sub
    Protected Overrides Sub OnMouseDown(ByVal e As System.Windows.Forms.MouseEventArgs)
        MyBase.OnMouseDown(e)
        _ClickDelta = e.Location
    End Sub
    Protected Overrides Sub OnMouseMove(ByVal e As System.Windows.Forms.MouseEventArgs)
        MyBase.OnMouseMove(e)
        If e.Button = Windows.Forms.MouseButtons.Left Then
            _GridOrigin += New Size(e.Location.X - _ClickDelta.X, e.Location.Y - _ClickDelta.Y)
            _ClickDelta = e.Location
            Invalidate()
        End If
    End Sub

But I need it to center on a picture box. I could take the normal route were you make the tiles move instead and create a  illusion that the map is moving but I thought it would be easier to just move the object its self and make the screen follow the position of the object instead.

The above is just a code snippet of course but I hope it helps explain what I'm attempting to do.

Answer 4

I made a video explaining it a little better and I came up with a solution kinda. So now the new question is how do you make the slide bar move left anr right using key strokes through code. The idea is get the slide bar to move when the player moves so it will move with the player.

Video:

http://youtu.be/9cjTQFJARlE

Edit:

I found this but i still have no clue how to control the scrollbar or how to force it to move only with the image/object:

http://msdn.microsoft.com/en-us/library/system.windows.forms.scrolleventargs.aspx#Y215

Answer 5

I found this sample but I dont know which sample ref to grab and it dont say. Here is link though maybe you guys can figure it out:

http://msdn.microsoft.com/en-us/library/system.windows.forms.scrollbar.scroll.aspx

Public Class Form1
    Private Sub HandleScroll(ByVal sender As [Object], ByVal e As ScrollEventArgs) Handles VScrollBar.Scroll, HScrollBar.Scroll
        'Create a graphics object and draw a portion of the image in the PictureBox. 
        Dim g As Graphics = PictureBox1.CreateGraphics()
        Dim xWidth As Integer = PictureBox1.Width
        Dim yHeight As Integer = PictureBox1.Height
        Dim x As Integer
        Dim y As Integer
        If (e.ScrollOrientation = ScrollOrientation.HorizontalScroll) Then
            x = e.NewValue
            y = VScrollBar.Value
        Else 'e.ScrollOrientation == ScrollOrientation.VerticalScroll
            y = e.NewValue
            x = HScrollBar.Value
        End If
        'First Rectangle: Where to draw the image. 
        'Second Rectangle: The portion of the image to draw.
        g.DrawImage(PictureBox1.Image, _
          New Rectangle(0, 0, xWidth, yHeight), _
          New Rectangle(x, y, xWidth, yHeight), _
          GraphicsUnit.Pixel)
        PictureBox1.Update()
    End Sub
End Class

Changed:

HScrollBar1 to HScrollBar

VScrollBar1 to VScrollBar

I think this would work just in reverse order i think. Right now I think the object moves based on scroll bar but I need that in reverse so I need help getting this sample to work. Says I need to add a refference from assebly but it does not say which refference to add. No clue were to grab it ethier.

Answer 6

Ok I found the refference to import but still not working, suggestions?

Imports System.Windows.Forms
'Added ref System.Windows.Forums 
Public Class Form1
    Private Sub HandleScroll(ByVal sender As [Object], ByVal e As ScrollEventArgs) Handles VScrollBar1.Scroll, HScrollBar1.Scroll
        'Create a graphics object and draw a portion of the image in the PictureBox. 
        Dim g As Graphics = PictureBox1.CreateGraphics()
        Dim xWidth As Integer = PictureBox1.Width
        Dim yHeight As Integer = PictureBox1.Height
        Dim x As Integer
        Dim y As Integer
        If (e.ScrollOrientation = ScrollOrientation.HorizontalScroll) Then
            x = e.NewValue
            y = VScrollBar1.Value
        Else 'e.ScrollOrientation == ScrollOrientation.VerticalScroll
            y = e.NewValue
            x = HScrollBar1.Value
        End If
        'First Rectangle: Where to draw the image. 
        'Second Rectangle: The portion of the image to draw.
        g.DrawImage(PictureBox1.Image, _
          New Rectangle(0, 0, xWidth, yHeight), _
          New Rectangle(x, y, xWidth, yHeight), _
          GraphicsUnit.Pixel)
        PictureBox1.Update()
    End Sub
End Class

Answer 7

Blue Line under :

VScrollBar1:Handle clause requires a WithEvents variable defined in containing type or one of its base types

HScrollBar1: Same error as above

Answer 8

You need to add WithEvents to your scroll bar definitions.

Answer 9

Thats the MSDN sample code though posted above,  I should not have to add anything else to it plus I dont know where you would even add it for it to even work as suggested on the MSDN sample.

Answer 10

It won't work with errors.  You'll either have to fix it or get rid of it.  Go to the scroll bar definitions and add WithEvents.

Answer 11

Please post a working sample then please I honestly dont think adding WithEvents will fix it but if you think it will please post a working sample of what you suggest please.

Answer 12

Please post a working sample then please I honestly dont think adding WithEvents will fix it but if you think it will please post a working sample of what you suggest please.

Post your current scroll bar definitions.

Answer 13

Everything I have is based off this sample from MSDN

http://msdn.microsoft.com/en-us/library/system.windows.forms.scrollbar.scroll.aspx

Ive put everythign back as they suggested and i'm still clueless why its not working. So please feel free to post your working sample.

Answer 14

Everything I have is based off this sample from MSDN

http://msdn.microsoft.com/en-us/library/system.windows.forms.scrollbar.scroll.aspx

Ive put everythign back as they suggested and i'm still clueless why its not working. So please feel free to post your working sample.

I was trying to help you correct the errors.  I don't seem to be helping.  Sorry.

Answer 15

Start over.

Your description is not clear - you can't force the screen to do anything.  Do you mean that you want to force a picture box to always be in the centre of your form?

Or are you talking about moving an image behind the picture box to create an illusion of movement across a map?  Because you then talk about tiles, moving the screen and an object. 

I cannot figure out what you are trying to do.  Your examples do not seem to match your task description.  You have mouse events and scroll bars.  If you are trying to centre a picture box within your form then mouse movements and scroll bars would not be relevant - you would be considering events such as the form loading, form resizing, or picture box resizing.  If you were talkin about an object on a moving map then you would be dealing with whatever events create movement in the object, which I think would be keystrokes. But since your task description is completely unclear, perhaps the examples are relevant after all. It's not possible to tell.

Answer 16

Sorry, I'll re-explain. I want the scrollbar to follow a picture box as you move the picutre box using keystrokes or key up and keydown event.

I know how to make a game using tile map and move tiles to create a illussion your moving when the brackground/tiles our moving not the player. But I thought it would be easier/less code if the player moved and the scroll bar will auto move following the player acting like a camera. So I grabed the sample fromt he MSDN that I posted above but the MSDN sample appears to not work for some reason.

Anyway, just need to know how make the scrollbar move via keydown event or automaticaly follow a picture box the player controls by keydown event. Does that make sense now? 

Answer 17

Anyway, just need to know how make the scrollbar move via keydown event or automaticaly follow a picture box the player controls by keydown event. Does that make sense now?

Set the scroll bar value to the value that represents the proportion that the player has moved across the map.   So if the player is at a position that represents 60% of the distance from the left, the horizontal scroll bar value should be at 60% of its total range. Set this value whenever the player's position within the scene changes, which could be on a keystroke event or could be due to some other gameplay, such as encountering a wormhole.

You could set the scroll bar values (min, max) to match the map values, and use the player position directly or (my preference) you could convert the player position to a percentage and set the scroll bar maximum to 100 and use the percentage figure to control the scrollbar.

Note that the scroll bar is not the best option for this form of display as it will be approximate only, due to issues with the width of the thumb. But it may be adequate for your purpose.

Answer 18

I made a form with two Buttons and a PictureBox. Button1 is aligned along the top of the form and is 30000 wide and 10 high in size. Button2 is aligned along the right side of the form and is 10 wide and 30000 high in size. PictureBox1 is 100 wide and 88 high and is initially located at coordinates for its top left corner at X 15000 and Y 15000. Pressing T makes the PictureBox move up but stay centered on the screen, V moves it down, D left and H right. You can see the horizontal or vertical scroll bar move as you press left right or up down buttons while the picturebox stays centered in the screen.

I also placed a zoom image as the background of Form1 so you could see the PictureBox moving across the image but it's hard to tell unless you increment the PictureBox movements at higher than + 1 or - 1 which can cause odd behaviour.

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.AutoScroll = True
        Me.WindowState = FormWindowState.Maximized
        Me.DoubleBuffered = True
        PictureBox1.Location = New Point(15000, 15000)
        KeyPreview = True
    End Sub

    Private Sub Form1_KeyDown(sender As Object, e As KeyEventArgs) Handles Me.KeyDown

        If e.KeyCode = Keys.T Then 'Up
            PictureBox1.Location = New Point(PictureBox1.Location.X(), PictureBox1.Location.Y() - 1)
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + 50, PictureBox1.Location.Y() - 384 + 44)
        End If
        If e.KeyCode = Keys.D Then 'Left
            PictureBox1.Location = New Point(PictureBox1.Location.X() - 1, PictureBox1.Location.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + 50, PictureBox1.Location.Y() - 384 + 44)
        End If
        If e.KeyCode = Keys.H Then 'Right
            PictureBox1.Location = New Point(PictureBox1.Location.X() + 1, PictureBox1.Location.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + 50, PictureBox1.Location.Y() - 384 + 44)
        End If
        If e.KeyCode = Keys.V Then 'Down
            PictureBox1.Location = New Point(PictureBox1.Location.X(), PictureBox1.Location.Y() + 1)
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + 50, PictureBox1.Location.Y() - 384 + 44)
        End If
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs)

    End Sub

    Private Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click

    End Sub

End Class

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You've taught me everything I know but not everything you know.

Answer 19

Thanks guys I'll test it to night, I have to go teach a class right now but this looks great. TY all for the help on this matter.

Answer 20

See my previous post. This new code will let you have a picturebox of any size.

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.AutoScroll = True
        Me.WindowState = FormWindowState.Maximized
        Me.DoubleBuffered = True
        PictureBox1.Location = New Point(15000, 15000)
        KeyPreview = True

    End Sub

    Private Sub Form1_KeyDown(sender As Object, e As KeyEventArgs) Handles Me.KeyDown

        If e.KeyCode = Keys.T Then 'Up
            PictureBox1.Location = New Point(PictureBox1.Location.X(), PictureBox1.Location.Y() - 1)
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - 384 + (Math.Round(PictureBox1.Width / 2)))
        End If
        If e.KeyCode = Keys.D Then 'Left
            PictureBox1.Location = New Point(PictureBox1.Location.X() - 1, PictureBox1.Location.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - 384 + (Math.Round(PictureBox1.Width / 2)))
        End If
        If e.KeyCode = Keys.H Then 'Right
            PictureBox1.Location = New Point(PictureBox1.Location.X() + 1, PictureBox1.Location.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - 384 + (Math.Round(PictureBox1.Width / 2)))
        End If
        If e.KeyCode = Keys.V Then 'Down
            PictureBox1.Location = New Point(PictureBox1.Location.X(), PictureBox1.Location.Y() + 1)
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - 384 + (Math.Round(PictureBox1.Width / 2)))
        End If
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs)

    End Sub

    Private Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click

    End Sub

End Class

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You've taught me everything I know but not everything you know.

Answer 21

This is like my previous post except it uses the mouse to move the PictureBox across the form by placing the mouse pointer at new coordinates and clicking one of the buttons. It's kind of ugly in that the PictureBox moves to the new location before the autoscroll catches up to the new coordinates.

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.AutoScroll = True
        Me.WindowState = FormWindowState.Maximized
        Me.DoubleBuffered = True
        PictureBox1.Location = New Point(15000, 15000)


    End Sub

    Private Sub Form1_MouseDown(sender As Object, e As MouseEventArgs) Handles Me.MouseDown
        If MousePosition.X() Or MousePosition.Y() Then
            PictureBox1.Location = New Point(MousePosition.X(), MousePosition.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - 683 + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - 384 + (Math.Round(PictureBox1.Width / 2)))
        End If

    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs)

    End Sub

    Private Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click

    End Sub

End Class

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You've taught me everything I know but not everything you know.

Answer 22

This is really useful stuff Monkey. Do you have any books you can suggest or sites you used to learn? You have only been here a short time but you seem to have made huge progress quickly. I'm amazed by your brilliant programing in such a short time. Two thumbs up bro.

Answer 23

The change to this code is to detect the primary screen working area width and height automatically instead of having 1366 / 2 and 768 / 2 hard coded into the program.

Public Class Form1

    Dim SPSWAW As Object = Screen.PrimaryScreen.WorkingArea.Width
    Dim SPSWAH As Object = Screen.PrimaryScreen.WorkingArea.Height
    Dim WAW As Integer = CInt(SPSWAW)
    Dim WAH As Integer = CInt(SPSWAH)

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.AutoScroll = True
        Me.WindowState = FormWindowState.Maximized
        Me.DoubleBuffered = True
        PictureBox1.Location = New Point(15000, 15000)
    End Sub

    Private Sub Form1_MouseDown(sender As Object, e As MouseEventArgs) Handles Me.MouseDown
        If MousePosition.X() Or MousePosition.Y() Then
            PictureBox1.Location = New Point(MousePosition.X(), MousePosition.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - ((WAW) / 2) + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - ((WAH) / 2) + (Math.Round(PictureBox1.Width / 2)))
        End If

    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs)

    End Sub

    Private Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click

    End Sub

End Class

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You've taught me everything I know but not everything you know.

Answer 24

Thanks for the feedback M Holmes. Basically I've learned from watching what all of the responders to OP's questions provide in their feedback in the form of code and explanations. I also resort to searching all MSDN forums and using the MSDN library a lot for help in resolving code issues. And I google for answers to questions which links to forums other than MSDN for the most part. Plus I post questions of my own sometimes and usually get replies PDQ from a variety of responders.

I can't cite any books for reference because I haven't read any so I am lacking in a lot of basic knowledge on programming anyhow. Sites I use to learn are mostly MSDN and Code Project though a variety of other sites I access from time to time if they contain relevant information to the task at hand.

Thanks again! :)

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You've taught me everything I know but not everything you know.

Answer 25

Here's the updated code that uses the Keys to move the PictureBox with the auto screen size detect added.

Public Class Form1

    Dim SPSWAW As Object = Screen.PrimaryScreen.WorkingArea.Width
    Dim SPSWAH As Object = Screen.PrimaryScreen.WorkingArea.Height
    Dim WAW As Integer = CInt(SPSWAW)
    Dim WAH As Integer = CInt(SPSWAH)

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.AutoScroll = True
        Me.WindowState = FormWindowState.Maximized
        Me.DoubleBuffered = True
        PictureBox1.Location = New Point(15000, 15000)
        KeyPreview = True

    End Sub

    Private Sub Form1_KeyDown(sender As Object, e As KeyEventArgs) Handles Me.KeyDown

        If e.KeyCode = Keys.T Then 'Up
            PictureBox1.Location = New Point(PictureBox1.Location.X(), PictureBox1.Location.Y() - 5)
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - ((WAW) / 2) + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - ((WAH) / 2) + (Math.Round(PictureBox1.Width / 2)))
        End If
        If e.KeyCode = Keys.D Then 'Left
            PictureBox1.Location = New Point(PictureBox1.Location.X() - 5, PictureBox1.Location.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - ((WAW) / 2) + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - ((WAH) / 2) + (Math.Round(PictureBox1.Width / 2)))
        End If
        If e.KeyCode = Keys.H Then 'Right
            PictureBox1.Location = New Point(PictureBox1.Location.X() + 5, PictureBox1.Location.Y())
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - ((WAW) / 2) + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - ((WAH) / 2) + (Math.Round(PictureBox1.Width / 2)))
        End If
        If e.KeyCode = Keys.V Then 'Down
            PictureBox1.Location = New Point(PictureBox1.Location.X(), PictureBox1.Location.Y() + 5)
            Me.AutoScrollPosition = New Point(PictureBox1.Location.X() - ((WAW) / 2) + (Math.Round(PictureBox1.Height / 2)), PictureBox1.Location.Y() - ((WAH) / 2) + (Math.Round(PictureBox1.Width / 2)))
        End If
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs)

    End Sub

    Private Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click

    End Sub

End Class

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You've taught me everything I know but not everything you know.