[RESOLVED] Graphics Rectangle

[dbasnett]

I am trying to have different types of rectangles. I thought something like this would work, but Rectangle is not a class.

    Public Class xRectangle
        Inherits Rectangle
    End Class

What I wanted this for was to remove a selection rectangle from an existing drawing. I have all of the objects to draw stored in a list and I am trying to remove the selection rectangle without removing the object it is covering. Hope this makes a little sense.

[jmcilhinney]

System.Drawing.Rectangle is a structure and you can't inherit structures, plain and simple. If you need a class that you can inherit then define your own base class and then inherit that. That base class can either wrap a Rectangle structure or define its own functionality from scratch.

[dbasnett]

Thanks jmc! I have been working on this since posting the question and as usual your advice is great. (BTW - I (borrowed, copied, used,...) some code you had written for a line that computed the rectangle for the line.)

Does this seem like the right direction?

Public MustInherit Class Shape
    Private _x, _y, _w, _h As Integer
    Private _spt, _ept As Point
    Private _r As Rectangle

    Public Sub New(ByVal spt As Point, ByVal ept As Point)
        'lines - thanks to jmc @ vbforums
        'define a rectangle for the line
...
    End Sub

    Public Sub New(ByVal x As Integer, ByVal y As Integer, ByVal w As Integer, ByVal h As Integer)
        'rectangle
...
    End Sub

    Public Property X() As Integer
        Get
            Return Me._x
        End Get
        Set(ByVal value As Integer)
            Me._x = value
        End Set
    End Property

    Public Property Y() As Integer
        Get
            Return Me._y
        End Get
        Set(ByVal value As Integer)
            Me._y = value
        End Set
    End Property

    Public Property Width() As Integer
        Get
            Return Me._w
        End Get
        Set(ByVal value As Integer)
            Me._w = value
        End Set
    End Property

    Public Property Height() As Integer
        Get
            Return Me._h
        End Get
        Set(ByVal value As Integer)
            Me._h = value
        End Set
    End Property

End Class





Public Class dRectangle
    Inherits Shape
    Public Sub New(ByVal X As Integer, ByVal Y As Integer, _
                   ByVal Width As Integer, ByVal Height As Integer)
        MyBase.New(X, Y, Width, Height)
    End Sub

It seems like it is starting to come together.

        Dim test As New dRectangle(0, 0, 10, 10)

[jmcilhinney]

At a glance, yes, although there's not much point having your _x, _y, _w and _h fields as well as _r, given that a Rectangle structure contains that same information. If you're going to wrap a Rectangle structure then you don't really need your own fields.

[dbasnett]

At a glance, yes, although there's not much point having your _x, _y, _w and _h fields as well as _r, given that a Rectangle structure contains that same information. If you're going to wrap a Rectangle structure then you don't really need your own fields.

Good point. I can't thank you enough. Some of your other posts are slowly getting me through understanding graphics. Yesterday for the first time I actually started to believe I might know what the hell was going on.