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c#asynchronouseventemitterblazor
Bercovici Adrian
Bercovici Adrian

Reputation: 9360

How to use asynchronous event-handler for emitted event?

I have a parent and a child component.In the child i emit an event to the parent.However i want this Action to be async since i want the parent to perform an async operation when he receives the event.How can i do this ?

Child

@functions{
[Parameter] protected Action onclose { get; set; }
[Parameter] protected  Action<bool> onsubmit { get; set; } //i want this handler to be async in the parent

string campaign; 
public async Task OnSubmitAsync() {
   var created = await this.service.CreateCampaignAsync(parameters);
        Console.WriteLine("Result of creation:" + created.ToString());
        this.onsubmit?.Invoke(created);
    }

Parent

 <CampaignForm onclose="@(()=>OnModalClosed())" onsubmit="@(async(x)=>OnSubmit(x))"></CampaignForm>
    @functions{
       public async Task OnSubmit(bool value) {
                //do some awaiting here 
       }
       public void OnModalClose()=>....; //do something sync ;
    }

Upvotes: 1

Views: 947

Answers (1)

enet
enet

Reputation: 45586

Do this on the child component:

@functions{
    // Define a property to store the Action delegate 
    [Parameter] protected  Action<bool> onsubmit { get; set; } 

    // More code here...

    public async Task OnSubmitAsync() {
   var created = await this.service.CreateCampaignAsync(parameters);
        Console.WriteLine("Result of creation:" + created.ToString());
        // Call back the parent's method
        onsubmit?.Invoke(created);
    }

 }

Do this on the parent component: Note that you should assign the identifier of the OnSubmit method to the func delegate attribute onsubmit (onsubmit="OnSubmit")

 <CampaignForm onclose="OnModalClosed" onsubmit="OnSubmit"></CampaignForm>
    @functions{
       public async void OnSubmit(bool value) {
                //do some awaiting here 
       }
       public void OnModalClose()=>....; //do something sync ;
    }

Hope this helps... Please mark my answer as accepted if it helped you out Hope this helps...

Upvotes: 1

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