Required parameters to blazor components

[montyclt]

Is your feature request related to a problem? Please describe.

I'm building a component where optional parameter doesn't make sense.

Describe the solution you'd like

Add required parameter to Parameter attribute

[Parameter(required = true)]
protected string Name { get; set; }

[Andrzej-W]

This is an old idea. It was moved from original Blazor repository to this #5455. Unfortunately it is now closed.

[montyclt]

Thank you @Andrzej-W. I close it as duplicate.

[Andrzej-W]

@montyclt Maybe you shouldn't close. As I wrote above issue #5455 was closed a few months ago but I'm afraid [Parameter(required = true)] hasn't been implemented yet and I cannot find any other tracking item for this.

[rynowak]

Reopening this. We do plan to do a feature like this but it won't happen in 3.0.

[mikewodarczyk]

The implementation of this may need to mix with the #nullable variable feature in c# 8. The null checks will flag [Parameter(required = true)] protected T myVar {get; set;} as uninitialized, but in fact this attribute is saying that the variable must be initialized; but it is initialized elsewhere.

[danroth27]

Clearing the milestone as I'd like to consider this for 5.0 now that we have a bunch of components that have required parameters.

[buddyfavors]

This could have came in handy for me too, for now I just wrapped the property.

        [Parameter]
        public string MessageText
        {
            get => _MessageText ?? throw new NotImplementedException();
            set => _MessageText = value;
        }

        private string _MessageText { get; set; }

[kattunga]

Is not possible to add this to 3.1?
now we to set #nullable disable in each params section to disable nullable warnings.