WinUI3-CustomControl: Cannot derived from sealed type 'ToggleSwitch'

Minh Van 171

Hi,

I want to create a custom control for toggle switch, but I only can derive from Control class rather than Toggle Switch class. I know that this is a sealed class, but any workaround or another approach for this? I want to dispose all dependency properties from ToggleSwitch to CustomToggleSwitch.

User's image

I know that it is better to use Style as a property but my project requires a control.

User's image

Thanks.

1 answer

Xiaopo Yang - MSFT 11,336 Reputation points Microsoft Vendor

2023-01-31T05:47:56.8566667+00:00

Hello,

Welcome to Microsoft Q&A!

You can implement your CustomToggleSwitch based on ToggleButton_themeresources.xaml.

Thank you.

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Minh Van 171 Reputation points

2023-02-01T02:30:57.9866667+00:00

Hi Xiaopo Yang,

Thanks for your suggestion. Could you show me how can I expose ALL dependency properties of ToggleSwitch from my CustomToggleSwitch class?

There is no OnConent, OffConent, IsOn... in the CustomToggleSwitch. Please see the image below to describe what I want to use this CustomToggleSwitch:

Xiaopo Yang - MSFT 11,336 Reputation points Microsoft Vendor

2023-02-01T02:59:44.5033333+00:00

You should create a control template when you want to customize a control's visual structure and visual behavior. for more information, see Quickstart: Control templates (XAML).

Minh Van 171 Reputation points

2023-02-01T04:34:12.47+00:00

Hi Xiaopo Yang,

I already read your link but I think my question is not how to use/modify control template.

I got the requirement is using CustomToggleSwitch and it must inherits all property dependency from default ToggleSwitch.

FYI, I can inherit from default TextBox, but I got error when I inherit from ToggleSwitch because of "Cannot derived from sealed type 'ToggleSwitch'" error.

The ultimate outcome of usage will be like this:

It means from XAML, a user does not have to specify any style or template. Only using myControls:CustomToggleSwitch. All styles will be declared inside CustomToggleSwitch class.

Thanks.

Xiaopo Yang - MSFT 11,336 Reputation points Microsoft Vendor

2023-02-01T05:17:35.74+00:00

You cannot inherit from ToggleSwitch. Your CustomToggleSwitch, in which you specify any style or template, can contain a ToggleSwitch control.
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