无法将类型"[ASValue]"的值<T>转换为预期的参数类型"绑定<C>"

Question

我正在构建一个自定义组件，并使用具有自定义泛型类型的ForEach。问题是这种类型抛出了这个错误：

无法将类型为"[ASValue]"的值转换为预期的参数类型"Binding">

public struct ArrayStepperSection<T: Hashable>: Hashable {
public let header: String
public var items: [ASValue<T>]

public init(header: String = "", items: [ASValue<T>]) {
self.header = header
self.items = items
}
}
public struct ASValue<T: Hashable>: Hashable {
private let id = UUID()
var item: T

public init(item: T) {
self.item = item
}
}
public class ArrayStepperValues<T: Hashable>: Hashable, ObservableObject {
@Published public var values: [ASValue<T>]
@Published public var selected: ASValue<T>
@Published public var sections: [ArrayStepperSection<T>]

public init(values: [ASValue<T>], selected: ASValue<T>, sections: [ArrayStepperSection<T>]? = nil) {
self.values = values
self.selected = selected

if sections != nil {
self.sections = sections!
} else {
self.sections = [ArrayStepperSection(items: values)]
}
}

public static func == (lhs: ArrayStepperValues<T>, rhs: ArrayStepperValues<T>) -> Bool {
return lhs.sections == rhs.sections
}
public func hash(into hasher: inout Hasher) {
hasher.combine(sections)
}
}
struct ArrayStepperList<T: Hashable>: View {
@Environment(.dismiss) var dismiss

@ObservedObject var values: ArrayStepperValues<T>

let display: (T) -> String

var body: some View {
List {
ForEach(values.sections, id: .self) { section in
Section(section.header) {
ForEach(section.items, id: .self) { item in // Error happens here
Button(action: {
values.selected.item = item
dismiss()
}) {
HStack {
Text(display(item))

Spacer()

if values.selected.item == item {
Image(systemName: "checkmark")
}
}
}
}
}
}
}
.listStyle(InsetGroupedListStyle())
.navigationTitle(Text(display(values.selected.item)))
}
}

Answer 1

这是我用来删除错误的测试代码：

struct ContentView: View {
@StateObject var values = ArrayStepperValues(values: [ASValue(item: "aaa"),ASValue(item: "bbb")], selected: ASValue(item: "aaa"))

var body: some View {
ArrayStepperList(values: values) // for testing
}
}
struct ArrayStepperList<T: Hashable>: View {
@Environment(.dismiss) var dismiss

@ObservedObject var values: ArrayStepperValues<T>

//   let display: (T) -> String   // for testing

var body: some View {
List {
ForEach(values.sections, id: .self) { section in
Section(section.header) {
ForEach(section.items, id: .self) { item in
Button(action: {
DispatchQueue.main.async {
values.selected.item = item.item  // <-- here
// dismiss()  // for testing
}
}) {
HStack {
Text("(item.item as! String)")  // for testing
Spacer()
if values.selected.item == item.item {  // <-- here
Image(systemName: "checkmark")
}
}
}
}
}
}
}
.listStyle(InsetGroupedListStyle())
//      .navigationTitle(Text(display(values.selected.item)))  // for testing
}
}