[02/03] Adding a picturebox to the main form from code.

[Sgt Spike]

Hey all,

I'm recreating an old board game on the computer using VB. This game has player tokens that have to be displayed on the screen. I used the "Component" class to create the definition of a player, from which I instantiate a player for each player that is playing. Within the class, I define a picturebox with an image inside to represent the player token.

Here's the problem - I can't get the token pictureboxes to appear on the screen. I am almost positive that it is because I am not putting them in a container. I tried to pass the form as a container to put the tokens on, but it errors out when I try to do that, saying it is an invalid cast. Here is the code for a new Player:

Public Sub New(ByVal Container As System.ComponentModel.IContainer, ByVal tempCash As Integer, ByVal tempPlaying As Integer, ByVal tempColor As String)
        MyClass.New(tempCash, tempPlaying, tempColor)
 
        'Required for Windows.Forms Class Composition Designer support
        Container.Add(Me)
    End Sub
 
    Public Sub New(ByVal tempCash As Integer, ByVal tempPlaying As Integer, ByVal tempColor As String)
        MyBase.New()
 
        'This call is required by the Component Designer.
        InitializeComponent()
 
        'Add any initialization after the InitializeComponent() call
        cash = tempCash
        colorName = tempColor
        playing = tempPlaying
        If tempColor = "Red" Then
            token.Image() = System.Drawing.Bitmap.FromFile("redpiece.png")
            color = System.Drawing.Color.FromArgb(255, 128, 128)
        ElseIf tempColor = "Blue" Then
            token.Image() = System.Drawing.Bitmap.FromFile("bluepiece.png")
            color = System.Drawing.Color.FromArgb(128, 128, 255)
        ElseIf tempColor = "Green" Then
            token.Image() = System.Drawing.Bitmap.FromFile("greenpiece.png")
            color = System.Drawing.Color.FromArgb(128, 255, 128)
        ElseIf tempColor = "Yellow" Then
            token.Image() = System.Drawing.Bitmap.FromFile("yellowpiece.png")
            color = System.Drawing.Color.FromArgb(255, 255, 128)
        ElseIf tempColor = "Black" Then
            token.Image() = System.Drawing.Bitmap.FromFile("blackpiece.png")
            color = System.Drawing.Color.Gray
        ElseIf tempColor = "White" Then
            token.Image() = System.Drawing.Bitmap.FromFile("whitepiece.png")
            color = System.Drawing.Color.White
        Else
            System.Console.WriteLine("Error in New() in Player.vb while trying to assign a color to the token")
        End If
 
        If playing = 1 Or playing = 2 Then
            token.Visible = True
            token.Location = spacesArray(0).getLocation
        End If
    End Sub

My error message ("Error in New()...") doesn't come up in the console, so it is assigning a picture to the token, and playing always = 1 at this point (eventually 0 will be not playing, 1 will be a human playing, and 2 will be a CPU playing). Any suggestions? Should I create a container on the form (like a panel) that is transparent and use that for the token positions?

[jmcilhinney]

I don't really know everything about your app but I don't really think that it's appropriate to have the Player class inherit Component or maintain a PictureBox. I would consider it more appropriate that the Player class merely inherit Object and maintain an Image object to represent its playing piece, letting the form worry about the PictureBox to display it.

[Fromethius]

umm.. just a note.. shouldn't u use select case?

[jmcilhinney]

umm.. just a note.. shouldn't u use select case?

Further to that, I'd be inclined to use a Color variable, which is limited to valid colours, where a String variable could theoretically be anything.

[Sgt Spike]

jmcilhinney - How would I let the form worry about the picturebox, but also be able to reference it from the Player object? I need to reset the picturebox's location each time the piece moves, and I'd like to do that straight from a function in the Player object. If there's a good way you can think of to change the location of the picturebox straight from the Player object, then let me know.

Fromethius - Yes I should use the select case statement, but I couldn't remember the exact syntax of it and I was too lazy to look it up. Elseifs are just easier to me, and I don't think it's any more system intensive (which doesn't matter in this case anyhow).

jmcilhinney again - I would be inclined to use a color variable also, and I would have, except that I am using the string elsewhere to tell what color's turn it is (i.e. "It's Red's turn now."). I'd also have to parse the original input that selects the color (a combobox) to a color, and I didn't want to deal with those complications.

[jmcilhinney]

jmcilhinney - How would I let the form worry about the picturebox, but also be able to reference it from the Player object? I need to reset the picturebox's location each time the piece moves, and I'd like to do that straight from a function in the Player object. If there's a good way you can think of to change the location of the picturebox straight from the Player object, then let me know.

You should think about whether that is appropriate in a properly designed OO application. I don't think it necessarily is but, as I said, I don't know everything about your application. I'm thinking that the Player might remember its colour and its position on the playing board, then the form would turn that information an actual Location.

I would be inclined to use a color variable also, and I would have, except that I am using the string elsewhere to tell what color's turn it is (i.e. "It's Red's turn now."). I'd also have to parse the original input that selects the color (a combobox) to a color, and I didn't want to deal with those complications.

No you wouldn't. You can quite easily get a Color object directly from a ComboBox. If you create a class or structure that has a property for a Color and a property for a String that represents that colour then you can bind an array of those objects directly to a ComboBox. You assign the String property to the DisplayMember, so that was what the user saw, and the Color property to the ValueMember, so that would be what you got from the SelectedValue property.

[Sgt Spike]

Makes sense... I guess I just don't like putting anything but calls to functions in the form code, but maybe I should change that habit a bit.

I'll give that a try too. Thanks for the help!