Passing method as parameter in blazor-CodePudding

I'm passing a method from a parent Blazor component into a child.

The parent definition looks like:

public bool AddOrUpdate(MyModel myModel)
{ 
    // do stuff
        
    return true;
}

In the ChildComponent.razor.cs it looks like:

[Parameter]
public EventCallback<MyModel> SaveMethod { get; set; }

And it's passed into the child from the parent like:

<ChildComponent SaveMethod="@AddOrUpdate" />

When I call the method in the child using

SaveMethod(newNote);

it throws:

Non invocable member cannot be used like a method

What's the issue?

EDIT: using invoke worked to get me past the initial error, but now I'm seeing CS1503 Argument 2: cannot convert from 'method group' to 'EventCallback'

CodePudding user response：

SaveMethod is a property. You should instead use SaveMethod.InvokeAsync(newNote); (and add await if you're inside of asynchronous method).

Read more about event callbacks here.

CodePudding user response：

This is not rocket science. Match the EventCalback method pattern to the assigned method and it works.

Here's a full working version of Enet's answer:

The model.

    public class MyModel
    {
        public string? Name { get; set; }
    }

The component

<button @onclick="SaveModel">Save</button>

@code {
    private MyModel _myModel => new MyModel() { Name= $"clicked at {DateTime.Now.ToLongTimeString()}" };

    [Parameter]
    public EventCallback<MyModel> SaveMethod { get; set; } 

    private void SaveModel()
    {
        // Invoke the parent's AddOrUpdate, passing it an instance of 
        // MyModel 
        SaveMethod.InvokeAsync(_myModel);
    } 
}

And Index page demo

@page "/"

<PageTitle>Index</PageTitle>

<MyComponent SaveMethod="this.AddOrUpdate" />

<div >
    @model.Name
</div>

@code {
    MyModel model = new MyModel();

    public void AddOrUpdate(MyModel myModel)
    {
        model = myModel;
    }
}