[RESOLVED] [2005] Hotspot for click on picture

[jre1229]

Hi,
I created a graphic that has some objects on it that I would like to use as buttons. To make the buttons look seamless, I want to have some sore of hotspot over top of what looks to be buttons but is actually part of one big graphic. Is there something in windows forms that is kinda like hotspots in web development? I tried adding a label over top of the button but I couldn't get the label to be invisible and still be able to take click events. I tried using the Transparent color on the "web" tab of the backcolor property but it still wasn't transparent.
Thanks

[Atheist]

There are plenty of ways to do this. Ive posted one way of doing it in the codebank. If you need strange clickable shapes you could have use for my example, but if you just need rectangular clickable areas you might aswell go for a simpler alternative.

[jre1229]

Thanks Atheist, that is a little more complex than what I am looking for. I just need a rectangle type label or button that is transparent. Is there a simplier method?

[Atheist]

Heres some code that will do what you want, its two examples in one, you can use the one that suits you the most.

Private Sub PictureBox1_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseClick
        If New Rectangle(30, 30, 100, 10).IntersectsWith(New Rectangle(e.X, e.Y, 1, 1)) Then
            MessageBox.Show("hey")
        End If
        'OR
        Dim x As Integer = e.X
        Dim y As Integer = e.Y
        If x >= 30 AndAlso x <= 130 AndAlso y >= 30 AndAlso y <= 40 Then
            MessageBox.Show("hey")
        End If
    End Sub

I would advice you to use the later option as it does not create any extra rectangle objects. Though the first option has its advantages aswell, but not in this case.

[dminder]

I am not understanding why you cannot use Labels too. Is the graphic always the same size or can it be resized?? If it is always the same size, then add a label where you want it and set these properties:

Visible=True
Enabled = True
BackColor = Transparent
Text = nothing
Autosize=false
borderStyle = none

These properties will give you what you want (you can now make the rectangle any size you want) and you can capture the click event of the label with no trouble.

You could also use GDI+ to create rectangles based on points and you can name them, add events (like click or mouseover). Some of that is beyond me, I know very very basic GDI+....for the moment

Good Luck,

D

[jre1229]

Thanks for the responses guys. Dminder, I tried that earlier but when you set the backcolor to transparent then it takes the color of main form, which puts a grey block on my picture. I believe I have come up with a way to do this though. I ended up taking my picture, cropping it into multiple pieces and then adding multiple picture boxes and piecing them together.

[dminder]

Do you have to use a picturebox?? I figured out why it worked on mine and not yours. Panels have a background image property. Mine was set so when I dumped a transparent label onto it, I had no problem.

However there is one other thing I thought of. At runtime you can set the parent of the label = the picturebox. This will force the transparency to take the background/backcolor of the picturebox and not the form.

For a moment, thought I lost my mind!!!

D

[Atheist]

Though I would say that using labels would be a bad practise. Labels are used to display text. You are catching the click event inside the labels boundaries, then why not just create a rectangle variable with the same boundaries and use it instead. That way you will not be having unneccessary controls on your form.

[dminder]

May I ask why it would be bad practice to use labels instead of manually having the program draw them? When you declare a new rectangle and give it the points to draw on, isn't it considered a control? So, when the app is running, it would be the same amount of controls on the form wouldnt it??

Not trying to be an arse here, I am truly curious. At some point I am sure I will come across the same issue and I want to have good practices in place. That way if anybody has to come behind me and work on something, I do not leave them with an unintelligable mess!!

Thanks!!!

D

[Atheist]

May I ask why it would be bad practice to use labels instead of manually having the program draw them? When you declare a new rectangle and give it the points to draw on, isn't it considered a control? So, when the app is running, it would be the same amount of controls on the form wouldnt it??

Not trying to be an arse here, I am truly curious. At some point I am sure I will come across the same issue and I want to have good practices in place. That way if anybody has to come behind me and work on something, I do not leave them with an unintelligable mess!!

Thanks!!!

D

Im certainly not trying to be an arse either.
A rectangle is not considered a control. Its just a Structure of X,Y, width and height variables.
Think about what is needed for this task, we need do specify an area that will respond to being clicked and we dont need for it to be drawn on the screen.
The rectangle is perfect for this job, and it is better if you look to performance (thought you would need alot of clickable labels to notice the difference).

Always use the tool thats best for the job

Its the same reason that you dont use an invisible listbox to store strings, you use a List(of String)

[dminder]

Thank you Atheist. I understand and totally agree with you. It was my understanding of what was considered a "control" that confuzzled me .....That or the medication for this lovely sinus infection....

And hey, when did we stop using invisible listboxes??
I miss all the good memos,

D

[jmcilhinney]

Just to add my two cents, I'd would inherit the PictureBox control and put the extra functionality in there. Here's a start:

'A collection of Rectangles.
Public Class RectangleCollection
    Inherits System.Collections.ObjectModel.Collection(Of Rectangle)
End Class
 
 
'Contains data for a HotSpotsClicked event.
Public Class HotSpotsClickedEventArgs
    Inherits System.EventArgs
 
    Private _hotSpots As RectangleCollection
 
    Public ReadOnly Property HotSpots() As RectangleCollection
        Get
            Return Me._hotSpots
        End Get
    End Property
 
    Public Sub New(ByVal hotSpots As RectangleCollection)
        Me._hotSpots = hotSpots
    End Sub
 
End Class
 
 
'A PictureBox with clickable hotspots.
Public Class ImageMapPictureBox
    Inherits PictureBox
 
    Private _hotSpots As RectangleCollection
 
    Public ReadOnly Property HotSpots() As RectangleCollection
        Get
            If Me._hotSpots Is Nothing Then
                Me._hotSpots = New RectangleCollection
            End If
 
            Return Me._hotSpots
        End Get
    End Property
 
    Public Event HotSpotsClicked As EventHandler(Of HotSpotsClickedEventArgs)
 
    Protected Overrides Sub OnMouseClick(ByVal e As System.Windows.Forms.MouseEventArgs)
        MyBase.OnMouseClick(e)
 
        Dim hotSpots As RectangleCollection = Nothing
 
        'Find each hotspot that contains the point that was clicked.
        For Each hotSpot As Rectangle In Me.HotSpots
            If hotSpot.Contains(e.Location) Then
                If hotSpots Is Nothing Then
                    hotSpots = New RectangleCollection
                End If
 
                hotSpots.Add(hotSpot)
            End If
        Next hotSpot
 
        If hotSpots IsNot Nothing Then
            'The mouse click occurred within at least one hotspot.
            Me.OnHotSpotsClicked(New HotSpotsClickedEventArgs(hotSpots))
        End If
    End Sub
 
    Protected Overridable Sub OnHotSpotsClicked(ByVal e As HotSpotsClickedEventArgs)
        RaiseEvent HotSpotsClicked(Me, e)
    End Sub
 
End Class

You can now add the Rectangles to the HotSpots property of the PictureBox and handle the HotSpotsClicked event to be notified when a hotspot is clicked and which one(s) it was.

[jre1229]

Thanks! I hope I am to your level of programming one day JMC. Is all of your knowledge self taught?

[jmcilhinney]

Thanks! I hope I am to your level of programming one day JMC. Is all of your knowledge self taught?

I taught myself VB.NET and C#, but I already had a computer science degree and two years industry experience in C/C++ so I can't take all the credit.

[jre1229]

Well you deserve a pat on the back because you are a tremendous help. I am learning but sometimes you just blow my mind. Thanks again!