How to chose a fillrectangle color form a listbox list entry?

Question

How to chose a fillrectangle color form a listbox list entry?

Štefan Mihael Rihar 181

It is never enough. Accessibility with PC Systems is for me easier to maintain without the internet. Although it is easier i started to have a homepgae with github pages. Maybe the tensions are not only therefore what ever therefore is for me. I asumed that i would have more hlep with a homepage related to visual basic dot net.
However. I am still not able to choose form a list a knowncolor to change the color of a fillrectangle. The file content
A VBdotNet Form1 FileContent ColourFields.txt

is my start to collect information for my tensions.
Brainstorming. Fillrectangle has to be used with brushes. Hm. The class brush with, a i asum, sturcture or enum brushes and the colornames with brushes is not the same, still i asum, as with the class color. the methods fromknowncolor and knowncolor show with intellisens in visual studio an error meassge if i use them with brushes.

For some controls i do not know if the controls can be reused or new dynamic link liberaries have to be build. I asume not. The next step i am not able to execute is to convert brushes names to numbers so that an index number from a list can be choosen instead.

To aim "building", typing my own properties i am missing some points and cannot pinpont them.

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Answer 1

Jiachen Li-MSFT 34,221 Microsoft External Staff

Hi @Štefan Mihael Rihar ,
Try the following code.

Imports System.ComponentModel  
Public Class Form1  
    WithEvents SmoothieMixer, BarrierField As New ListBox  
    WithEvents LabelRectangle As New MyLabel  
  
    Public ColorObjList As New ArrayList  
  
    Public Sub New()  
  
        Dim ColorNames(), ColorName As String  
        ColorNames = System.Enum.GetNames(GetType(KnownColor))  
        Dim cnvrt As TypeConverter = TypeDescriptor.GetConverter(GetType(KnownColor))  
  
        For Each ColorName In ColorNames  
            ColorObjList.Add(Color.FromKnownColor(cnvrt.ConvertFromString(ColorName)))  
        Next  
  
        Dim list1 As New List(Of Rectangle)()  
        For i As Integer = 0 To 10  
            list1.Add(New Rectangle(10, i * 2, 50, 50))  
        Next  
  
        ' Dieser Aufruf ist für den Designer erforderlich.  
        InitializeComponent()  
  
        SmoothieMixer.DataSource = list1  
        With SmoothieMixer  
            .Location = New Point(50, 50)  
            .Size = New Size(200, 160)  
        End With  
  
        BarrierField.DataSource = ColorObjList  
        With BarrierField  
            .Location = New Point(350, 50)  
            .Size = New Size(200, 160)  
        End With  
  
        With LabelRectangle  
            .Location = New Point(10, SmoothieMixer.Bottom + 10)  
            .Size = New Size(100, 100)  
            .BorderStyle = BorderStyle.FixedSingle  
            .squaresnippet = list1(0)  
        End With  
        Controls.AddRange({SmoothieMixer, BarrierField, LabelRectangle})  
        ' Fügen Sie Initialisierungen nach dem InitializeComponent()-Aufruf hinzu.  
  
    End Sub  
  
    Private Sub SmoothieMixer_SelectedIndexChanged(sender As Object, e As EventArgs) Handles SmoothieMixer.SelectedIndexChanged  
        Dim lb As ListBox = CType(sender, Control)  
        LabelRectangle.squaresnippet = lb.SelectedItem  
        LabelRectangle.Invalidate()  
    End Sub  
  
    Private Sub BarrierField_SelectedIndexChanged(sender As Object, e As EventArgs) Handles BarrierField.SelectedIndexChanged  
        Dim lb As ListBox = CType(sender, Control)  
        LabelRectangle.squarecolor = lb.SelectedItem  
        LabelRectangle.Invalidate()  
    End Sub  
  
    Public Class MyLabel  
        Inherits Label  
        Public squaresnippet As Rectangle  
        Public squarecolor As Color  
        Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)  
            Using br = New SolidBrush(squarecolor)  
                If squaresnippet <> Nothing Then  
                    e.Graphics.FillRectangle(br, squaresnippet)  
                End If  
            End Using  
        End Sub  
    End Class  
End Class

Best Regards.
Jiachen Li

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Štefan Mihael Rihar 181 Reputation points

2022-08-04T07:52:29.687+00:00
What i have changed is

Dim ColorNames(), ColorName As String

to

Dim ColorNames() As String Public ColorObjList As New ArrayList

to

Dim ColorObjList As New List(Of Color)() For Each ColorName In ColorNames ColorObjList.Add(Color.FromKnownColor(cnvrt.ConvertFromString(ColorName))) Next

to

For ColorName As Integer = 0 To 174 ColorObjList.Add(Color.FromKnownColor(cnvrt.ConvertFromString(ColorName))) Next

and added to MyLabel the property

.squarecolor = ColorObjList(0)

The error message has been "Die angegebene Umwandlung ist ungültig".
For my further researches i have found an info with the site stackoverflow that states

combobox.DataBindings.Add - Adds the specified Binding to the (Existing)collection.

combobox.DataSource - Gets or sets the data source(new) for this ComboBox.

in my case

ListBox

My personal aim for simplicity is to put storaga units to a calculator for "DataSource" entries
and to change the storage units with an use of the calculator for "DataBindings".

The Syntax for a race in the circle is for me not obvious. If a focus for a control is not the with a control that is meanwhile a storage unit with the runtime environment maybe like textstreaming in a await state
i take my time to aim the next step.
The first entry in the rectangle list is not the same as the first entry in the color list. I acnnot recognize waht i am missing to understand the error message.
Jiachen Li-MSFT 34,221 Reputation points Microsoft External Staff

2022-08-04T08:28:20.543+00:00

Hi @Štefan Mihael Rihar ,
May I know if your problem has been solved or not?
If solved, you could accept the helpful answer to change its status to Answered. It will also help others to solve the similar issue.
Thanks for your cooperation.
Štefan Mihael Rihar 181 Reputation points

2022-08-04T15:06:31.45+00:00

My problem has not been solved also due to the error message.
Jiachen Li-MSFT 34,221 Reputation points Microsoft External Staff

2022-08-05T04:14:10.663+00:00

Hi @Štefan Mihael Rihar ,
Have you tried my code?
In my tests it worked.
Štefan Mihael Rihar 181 Reputation points

2022-08-05T06:13:50.647+00:00

Yes i have tried the, your, code. First i copied and pasted the, my, code from the textfile i saved to my post
to my project.
Then i selected the "SelctedIndexChanged" Event and the MyLabel Class.
I pasted your code and pressed F5 in Visual Studio. The color is changeing.
But only the color is changeing. I added then the additional line for the square coordinates. To choose
also the list entries from the first ListBox on the left side.
Then i tried again and choosing a color again lead to an error message.
Your code works fine in addition to mine but without the possibilty to change the rectangle coordinates.
I work for an answer with both possibilities.
Jiachen Li-MSFT 34,221 Reputation points Microsoft External Staff

2022-08-05T06:32:06.24+00:00

Hi @Štefan Mihael Rihar ,
I edited my answer to add the full code.
Here is my test reslut.
Štefan Mihael Rihar 181 Reputation points

2022-08-05T06:40:18.927+00:00

With the pasted code i can go on to find my weak steps. Thank you.
As usual i have been blind. In this case i have not concidered that the second ListBox has
also to be maintained with the SelectedIndexChanged Event for the additional ListBox.

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How to chose a fillrectangle color form a listbox list entry?

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