将方法传递给组件 [英] Passing method to component

问题描述

我一直在尝试找出可能的方法以及如何将方法从主页传递到 Blazor 中的组件中.

I have been trying to work out how if its possible and how to pass a method from the main page into a component in Blazor.

我有一个简单的剃​​刀页面，其中包含一个带有按钮的组件.我想将剃刀页面的 onclick 方法传递给组件中的按钮

I have a simple razor page, which contains a component with a button. I want to pass the onclick method from the razor page to the button in the component

注意:我不需要这个方法来返回任何无效的东西.我只需要能够在组件上的按钮中从主页调用方法.我只是在这里添加 int 作为猜测，因为它在抱怨 T

Note: I do not need this method to return anything void is fine. I just need to be able to call a method from the main page in a button on the component. I only added int here as a guess since it was complaining about T

@page "/test"
@using Testing.Client.Model;
@using System.Threading;

<TestMethodPassing ExternalMethod="@btnClick"></TestMethodPassing>

@code {

    public Action<int> btnClick(){ return 1;}

}

组件模型

public class TestingMethodPassingModel : ComponentBase
{
    [Parameter]
    protected Action<int> ExternalMethod { get; set; }
}

组件

@inherits TestingMethodPassingModel;
@using testing.Client.Model;
@using System.Threading;


<button class="btn btn-primary" @onclick="@ExternalMethod" autofocus>External button</button>


@code {


    }

错误

上面的代码给了我以下错误

Errors

The above code gives me the following error

btnClick"没有重载匹配委托Action"

Gives me No overload for 'btnClick' matches delegate 'Action'

我也尝试过类型 T 并且失败了，因为 Blazor 由于某种原因无法找到类型 T 的引用

I tried doing type T as well and that failed as Blazor cant for some reason find the reference for type T

从答案中拼凑出来的工作示例.PassingMethodToComponent

Working example pieced together from the answers. PassingMethodToComponent

推荐答案

下面是一个将方法从父级传递给子级并由子级调用它的示例.由于您不需要返回值，我只是使用 Action 而不是 Action.

Here is an example of passing a method from a parent to a child and the child invoking it. As you don't require a return value I'm just using Action rather than Action<T>.

有很多方法可以让这段代码更紧凑，但我已经找了一个更详细的例子，希望能更好地展示正在发生的事情.

There are many ways you can make this code more compact, but I've gone for a more verbose example to hopefully show what's happening a bit better.

父组件:

@page "/"

<h1>Hello, world!</h1>

Welcome to your new app.

<Child ParentMethod="@SayHello" />

@code {

    private void SayHello()
    {
        Console.WriteLine("Hello!");
    }

}

子组件:

<h3>Child</h3>

<button @onclick="@InvokeParentMethod">Click Me!</button>

@code {

[Parameter] public Action ParentMethod { get; set; }

private void InvokeParentMethod()
{
    ParentMethod?.Invoke();
}

}

这篇关于将方法传递给组件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！