.netvb.netwinformscontrolspowerpacks

How to reference a dynamically created OvalShape with a string variable in vb.net


I have created 40 or so OvalShapes from MS power packs and when the user clicks them they send an ID to separate function that is supposed to change the color of the clicked oval. Unfortunately the Controls method seems to not work.

Controls.Item(Dummy).fillcolor = Color.Red gives me an error saying "FillColor is not a member of 'System.Windows.Forms.Control'" where Dummy is the string containing the name of the control.

I'm fairly new to VB.NET so I'm not sure if there's another way to reference things on the form via a string besides using Controls. Google hasn't really helped on this matter too much, all I found was a way to search through all shapes using the CType on all controls that match the oval type which isn't helpful when I just want to change one control...

Edit: I am looking to be able to do something like the following:

For i = 1 to 40
     OvalName = "Oval" & i
     if Ovali = then do something
Next

Solution

  • I am not sure how you are adding your OvalShapes or what type of container you are using. In order to add them to a Windows Form Control you will need to use the shapeContainer as mentioned by Slaks. In this example I am creating a shapeContainer and adding it to the Form, then I am using the shapeContainers.Shapes.Add Method to add the oval to the ShapeCollection Class. I also am attaching an eventhandler to the Click Event of the Ovals so that I can access the calling Shape to change its fill color through the sender object of the EventHandler. See if this will work for you.

    Imports Microsoft.VisualBasic.PowerPacks
    Public Class Form1
        Dim offset As Integer = 0
        Dim OvalContainer As New ShapeContainer
    
        Public Sub New()
    
            ' This call is required by the designer.
            InitializeComponent()
            OvalContainer.Size = New Size(Me.Width, 50)
            Me.Controls.Add(OvalContainer)
            OvalContainer.Location = New Point(0, 0)
        End Sub
    
        Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
            Dim oval As New OvalShape()
    
            oval.Size = New Size(30, 40)
            oval.Location = New Point(offset, 0)
            oval.FillStyle = FillStyle.Solid
            oval.FillColor = Color.Transparent
            oval.BorderColor = Color.Black
            oval.BorderWidth = 2
            AddHandler oval.Click, AddressOf ShapeClick
            OvalContainer.Shapes.Add(oval)
    
            offset += 40
        End Sub
    
        Private Sub ShapeClick(sender As Object, e As EventArgs)
    
            Dim oval As OvalShape = DirectCast(sender, OvalShape)
            If oval.FillColor.Equals(Color.Red) Then
                oval.FillColor = Color.Blue
            Else
                oval.FillColor = Color.Red
            End If
    
        End Sub
    
    End Class
    

    Edit per OP's clarification

    When you create your ovals add oval.Name = "oval" & index this will add the name property that will enable the following code to work.

    You can iterate through the Shapes Collection like this(this is based off of my above example):

    For Each o As OvalShape In OvalContainer.Shapes
        If o.Name = "oval1" Then o.FillColor = Color.Azure
    Next
    

    or you can search for the exact Oval that you are looking for by using the ShapeContainer.Shapes.IndexOfKey Method

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Dim index As Integer = OvalContainer.Shapes.IndexOfKey("oval1")
        If index >= 0 Then
            DirectCast(OvalContainer.Shapes(index), OvalShape).FillColor = Color.Purple
        End If
    End Sub