SwiftUI 如何在 C# 中使用“Delegate-EventHandler-EventArgs"方式将数据从子级传递到父级 [英] SwiftUI How to pass data from child to parent as done in C# with the 'Delegate-EventHandler-EventArgs' way

问题描述

我已经阅读了这个主题SwiftUI - 按钮 - 如何将函数(带参数)请求从子进程传递给父进程然而，在原始海报编辑了他自己的答案之后，他提出了一种与他自己的问题不符的方法.不幸的是，我还没有达到足够的分数来在此线程中发表评论

I have already read this thread SwiftUI - Button - How to pass a function (with parameters) request to parent from child however after the original poster edited his own answer he proposed a way that didn't match his own question. Unfortunately I have not yet reached enough points to post comments in this thread

这是上面帖子中重复解释问题的代码示例:

This is the code example from the post above repeated to explain the problem:

struct ChildView: View {
    var function: () -> Void

    var body: some View {
        Button(action: {
            self.function()
        }, label: {
            Text("Button")
        })
    }
}

struct ContentView: View {
    var body: some View {
        ChildView(function: { self.setViewBackToNil() })
    }

    func setViewBackToNil() {
        print("I am the parent")
    }
}

现在我想给 setViewBackToNil(myStringParameter: String) 添加一个 String 参数

And now I want to add a String parameter to setViewBackToNil(myStringParameter: String)

推荐答案

这里是可能的解决方案.使用 Xcode 11.4/iOS 13.4 测试

Here is possible solution. Tested with Xcode 11.4 / iOS 13.4

struct ChildView: View {
    var function: (String) -> Void

    @State private var value = "Child Value"
    var body: some View {
        Button(action: {
            self.function(self.value)
        }, label: {
            Text("Button")
        })
    }
}

struct ContentView: View {
    var body: some View {
        ChildView { self.setViewBackToNil(myStringParameter: $0) }
    }

    func setViewBackToNil(myStringParameter: String) {
        print("I am the parent: \(myStringParameter)")
    }
}

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