How add value changed logic when using @bind-Value?

[Strypper]

<FluentDatePicker Label="Deadline" @bind-Value="@Content.Deadline" />

Like this example ValueChanged will duplicate with @bind-Value

[dvoituron]

Hi, I don't quite understand your problem or question. Could you give me more details?

[Strypper]

If I use @bind-Value then I cannot use ValueChanged because of this error

The component parameter 'ValueChanged' is used two or more times for this component. Parameters must be unique (case-insensitive). The component parameter 'ValueChanged' is generated by the '@bind-Value' directive attribute.		

[dvoituron]

Yes, this is the classic Blazor way for Two-way binding.

Two-way binding in Blazor uses a naming convention. If we want to bind to a property named SomeProperty, then we need an event call-back named SomeProperyChanged. This call-back must be invoked any time the component updates SomeProperty.
https://blazor-university.com/components/two-way-binding/

See also

• https://learn.microsoft.com/en-us/aspnet/core/blazor/components/data-binding

[KurimasuTanaka]

It's also possible to bind Switch value to a parameter and write additional logic in setter.

<Switch Label="Value" @bind-Value="bindedValue" />

@code {
    private bool _bindedValue;
    [Parameter]
    public bool bindedValue {
        get => _bindedValue;
        set 
        {
             //your custom logic
        }
    }

[vnbaaij]

For .NET 7 and higher you can use @bind-...:after to specify a method that is called after the binding takes place. So, for example:

@bind-Value="@SearchTerm" @bind-Value:after="@StartNewSearchAsync"

[woaidianqian]

I would like to add something

                                          
 <FluentSwitch @bind-Value="proposalSwitchValue" @bind-Value:after="async () => {await OnProposalSwitchChanged(proposalSwitchValue); }" CheckedMessage="On" UncheckedMessage="Off" >
                                                

@bind-Value="proposalSwitchValue" @bind-Value:after="async () => {await OnProposalSwitchChanged(proposalSwitchValue); }``