Is components as Container needed for all custom controls?

Question

Is components as Container needed for all custom controls?

Peter Volz 1,295

Hello, I'm learning designing of .net framework WinForms controls In a custom control I've seen:

Private components As System.ComponentModel.IContainer

and:

    Protected Overrides Sub Dispose(ByVal Disposing As Boolean)
        Try
            If Disposing AndAlso components IsNot Nothing Then
                components.Dispose()
            End If
        Finally
            MyBase.Dispose(Disposing)
        End Try
    End Sub

also in Private Sub InitializeComponent() :

Me.components = New System.ComponentModel.Container()

But this custom control has an ImageList component When designing my own custom control, which does not have any component (such as Image List) should I still insert the above code to my custom control? My custom control inherits the Panel with 1 Button and 1 TextBox inside, nothing more.

Jiachen Li-MSFT 34,216 Reputation points Microsoft External Staff

2023-04-20T08:08:39.3833333+00:00

May I know if you have any update about the problem?

1 answer

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Jiachen Li-MSFT 34,216 Reputation points Microsoft External Staff

2023-04-20T08:08:39.3833333+00:00

May I know if you have any update about the problem?

Answer 1

Castorix31 90,441

No, it is not needed. You can see MSDN samples for basic Custom Controls, like : How to: Develop a Simple Windows Forms Control

S-Soft 666 Reputation points

2023-04-12T11:07:03.4966667+00:00
Thank you a lot, I really appreciate it. However, seems this single line is still needed, am I right?

Private components As System.ComponentModel.Container = Nothing
Castorix31 90,441 Reputation points

2023-04-12T11:14:35.9433333+00:00

Not inside the Custom Control. This line is similar as the line in Form1.Designer.vb for Windows Form Designer
S-Soft 666 Reputation points

2023-04-12T12:11:11.91+00:00

Thank you again, yep removing them caused no problem. if you don't mind, please kindly give me one more tip, to keep this leftover or remove this too? Protected Overrides Sub Dispose(ByVal Disposing As Boolean) MyBase.Dispose(Disposing) End Sub
Castorix31 90,441 Reputation points

2023-04-12T12:55:05.4966667+00:00

It is generally not needed, but it depends on the complexity of the control.

I already used it when I had to release COM interfaces for example.

But in most of MS samples, it is not used. For example, a simple Custom Control : https://github.com/uri247/Win81App/blob/605e2b14dfe584342c4e1a016cc6af4cc794543f/XAML%20user%20and%20custom%20controls%20sample/VB/ImageWithLabelControl.vb

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Is components as Container needed for all custom controls?

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