public class ChildBase : ComponentBase
{

	[Parameter]
	public EventCallback<Baz> OnSendBaz { get; set; }

	[Inject]
	public IFooService FooService { get; set; }
	
	protected Bar Bar { get; set; }
	
	protected override void OnInitialized()
	{
		Bar = new Bar();
	}

	protected async Task OnClickSend(MouseEventArgs args)
	{
	
		var baz = FooService.GetBaz(id: Bar.Id);
		
		//Modal.Hide();
		
		await OnSendBaz.InvokeAsync(baz);
	}
}

@inherits ChildBase

<div class="form-group">
	<input type="button" class="btn btn-primary btn-sm" id="" value="Send" />
</div>

public class ParentBase : ComponentBase
{
	protected Baz ReceivedBaz { get; set; }
	
	protected override void OnInitialized()
	{
		ReceivedBaz = new Baz() { Id = 0};
	}

	protected async Task OnReceiveBaz(Baz baz)
	{
		ReceivedBaz = baz;
	}
}

@inherits ParentBase

<label>Baz ID: @ReceivedBaz.Id</label>

<Child OnSendBaz="OnReceiveBaz"></Child>

//
// parent component
//

<ChildComponent @ref="@Child" />

<button onClick="@ShowModal">Show Child Modal</button>


@code{

    protected ChildComponent Child {get; set;}; 

    void ShowModal(){
	
        Child.Modal.Show();
		
    }
}