在typescript和knockout中使用viewmodel时出现"this"问题

Question

请参阅下面的更新代码

我正在尝试使用打字稿和打字稿,但似乎我无法将我的打字稿视图模型绑定到我的视图......似乎我有一个问题,this但我不明白为什么...

在this.UserList调用的时候是不确定的Fill方法

这是我的viewModel:

module ViewModels {
    export class UserViewModel {

        constructor() {
            this.UserList = ko.observableArray<KnockoutObservable<Models.User>>([]);

            this.RemoveItem = <(user: KnockoutObservable<Models.User>) => void> this.RemoveItem.bind(this);
            this.AcceptItem = <(user: Models.User) => void> this.AcceptItem.bind(this);
            this.AddItem = <() => void> this.AddItem.bind(this);
        }

        public UserList: KnockoutObservableArray<KnockoutObservable<Models.User>>;
        public Fill() {
            $.ajax({
                type: "POST",
                url: "/Guest/LoadGuest/",
                success: data=> {
                    $(data).each((index: any, item)=> {
                        var guest = new Models.User();
                        guest.FirstName = ko.observable(item.firstName);
                        guest.LastName = ko.observable(item.lastName);
                        guest.IsNew = ko.observable(false);
                        this.UserList.push(ko.observable(guest));
                    });
                }
            });
        }

        public AddItem() {
            var guest = new Models.User();
            guest.FirstName = ko.observable("");
            guest.LastName = ko.observable("");
            guest.IsNew = ko.observable(true);

            this.UserList.push(ko.observable(guest));
        }

        public AcceptItem(user: Models.User) {
            user.IsNew = ko.observable(false);
        }


        public RemoveItem(user: KnockoutObservable<Models.User>) {
            this.UserList.remove(user);
        }


    }
}

这是我的观点:

<table>
    <thead>
        <tr><th>Prénom</th><th>Nom de famille</th></tr>
    </thead>
    <tbody data-bind="foreach: UserList">
        <tr data-bind="if:IsNew">
            <td><input type="text" data-bind="text: FirstName" /></td>
            <td><input type="text" data-bind="text: LastName" /></td>
            <td><a data-bind="click:$parent.AcceptItem">OK</a><a data-bind="click:$parent.RemoveItem">Annuler</a></td>
        </tr>
        <tr data-bind="if:!IsNew">
            <td data-bind="text: FirstName"></td>
            <td data-bind="text: LastName"></td>
            <td></td>
        </tr>
    </tbody>
</table>
<a id="AddGuest" data-bind="click:AddItem">Add</a>

@section scripts{
    <script src="~/Scripts/models/ModelBase.js"></script>
    <script src="~/Scripts/models/User.js"></script>
    <script src="~/Scripts/viewmodels/UserViewModel.js"></script>
    <script>

        var vm = new ViewModels.UserViewModel();
        vm.Fill();
        ko.applyBindings(vm);
    </script>

}

这是我的模型:

 module Models{

     export class User extends Models.ModelBase {
         constructor() {
             super();

         }

         public FirstName: KnockoutObservable<string>;
         public LastName: KnockoutObservable<string>;
         public Age: KnockoutObservable<Age>;
     }

     export class Age {
         public ID: KnockoutObservable<number>;
         public Description: KnockoutObservable<string>;
     }
 }

帮助目的的新工作代码:

视图模型:

module ViewModels {
    export class UserViewModel {
        constructor() {

        }

        public UserList: KnockoutObservableArray<Models.User> = ko.observableArray<Models.User>([]);
        public Fill = () => {
            $.ajax({
                type: "POST",
                url: "/Guest/LoadGuest/",
                success: data=> {
                    for (var i = 0; i < data.length; i++) {
                        var item = data[i];
                        var guest = new Models.User();
                        guest.FirstName(item.firstName);
                        guest.LastName(item.lastName);
                        guest.Age().Description("Test Age");
                        guest.IsNew(false);
                        this.UserList.push(guest);
                    }
                }
            });
        }

        public AddItem = () => {
            var guest = new Models.User();
            guest.FirstName = ko.observable("");
            guest.LastName = ko.observable("");
            guest.IsNew(true);
            this.UserList.push(guest);

        }

        public AcceptItem = (user: Models.User) => {
            user.IsNew(false);
        }

        public RemoveItem = (user: Models.User)  => {
            this.UserList.remove(user);
        }

    }
}

模型:

 module Models{

    export class ModelBase{
        constructor() {
            this.IsNew = ko.observable(false);
        }
        public IsNew: KnockoutObservable<boolean>;
    }

     export interface IUser {
         FirstName: KnockoutObservable<string>;
         LastName: KnockoutObservable<string>;
         Age: KnockoutObservable<Age>;
     }


     export class User extends Models.ModelBase implements IUser {
         constructor() {
             super();
             this.FirstName = ko.observable("");
             this.LastName = ko.observable("");
             this.Age = ko.observable(new Age());
         }

         public FirstName: KnockoutObservable<string>;
         public LastName: KnockoutObservable<string>;
         public Age: KnockoutObservable<Age>;
     }

     export class Age {
         constructor() {
             this.ID = ko.observable(null);
             this.Description = ko.observable("");
         }

         public ID: KnockoutObservable<number>;
         public Description: KnockoutObservable<string>;
     }
 }

视图:

<table>
        <thead>
            <tr><th>Prénom</th><th>Nom de famille</th><th>Age</th></tr>
        </thead>
        <tbody data-bind="foreach: UserList">
            <tr data-bind="ifnot:$data.IsNew">
                <td data-bind="text: FirstName"></td>
                <td data-bind="text: LastName"></td>
                <td data-bind="text: Age().Description"></td>
            </tr>
            <tr data-bind="if:$data.IsNew">
                <td><input type="text" data-bind="value: FirstName" /></td>
                <td><input type="text" data-bind="value: LastName" /></td>
                <td><input type="text" data-bind="value: Age().Description" /></td>
                <td><a data-bind="click:$root.AcceptItem">OK</a><a data-bind="click:$root.RemoveItem">Annuler</a></td>
            </tr>
        </tbody>
</table>


    <a id="AddGuest" data-bind="click:AddItem">Add</a>
@section scripts{
    <script src="~/Scripts/models/ModelBase.js"></script>
    <script src="~/Scripts/models/User.js"></script>
    <script src="~/Scripts/viewmodels/UserViewModel.js"></script>
    <script>
        var vm = new ViewModels.UserViewModel();
        vm.Fill();
        ko.applyBindings(vm);
    </script>

}

Answer 1

如果你想this受到约束UserViewModel,那么也许可以使用这种方法:

module ViewModels {
    export class UserViewModel {

        UserList: KnockoutObservableArray<KnockoutObservable<Models.User>> = ko.observableArray<KnockoutObservable<Models.User>>([]);

        Fill = () => {
            $.ajax({
                type: "POST",
                url: "/Guest/LoadGuest/",
                success: data => {
                    $(data).each((index: any, item)=> {
                        var guest = new Models.User();
                        guest.FirstName = ko.observable(item.firstName);
                        guest.LastName = ko.observable(item.lastName);
                        guest.IsNew = ko.observable(false);
                        this.UserList.push(ko.observable(guest));
                    });
                }
            });
        }

        AddItem = () => {
            var guest = new Models.User();
            guest.FirstName = ko.observable("");
            guest.LastName = ko.observable("");
            guest.IsNew = ko.observable(true);

            this.UserList.push(ko.observable(guest));
        }

        AcceptItem = (user: Models.User) => {
            user.IsNew = ko.observable(false);
        }


        RemoveItem = (user: KnockoutObservable<Models.User>) => {
            this.UserList.remove(user);
        }
    }
}

这是一个TypeScript Playground来演示

您可以阅读此处使用的方法的说明:http://blogs.msdn.com/b/typescript/archive/2013/08/06/announcing-0-9-1.aspx(选中"更好'这个'处理)

顺便说一下,我怀疑KnockoutObservable<Models.User>你应该拥有的实际拥有的地方Models.User以及this.UserList.push(ko.observable(guest));你实际应该拥有的地方this.UserList.push(guest);.我没有更改代码示例,以防我错过了什么.

Answer 2

这里的其他答案假设您对问题的描述是准确的.我决定实际测试你的代码.这是我发现的:

1. each功能错误.

   $(data).each((index: any, item)=> {
   

   这可能在技术上有效,但它应该适用于DOM节点.你应该用$.each.

   $.each(data, (index: any, item)=> {
   

2. 在可观察的环境中包装视图模型对象.

   this.UserList.push(ko.observable(guest));
   

   这会破坏你的RemoveItem功能.你应该只添加对象.

   this.UserList.push(guest);
   

3. 覆盖一个observable而不是设置它.

   user.IsNew = ko.observable(false);
   

   淘汰赛将无法在这里看到变化.您需要设置observable.

   user.IsNew(false);
   

4. 对<input>元素使用错误的绑定.

   <td><input type="text" data-bind="text: FirstName" /></td>
   

   该text绑定是单向的.你需要使用value.

   <td><input type="text" data-bind="value: FirstName" /></td>
   

5. 在表达式中不正确地使用observable.

   <tr data-bind="if:!IsNew">
   

   这测试了observable本身是否false,它始终不是(因为它是一个函数).您想测试observable的值是否为false:!IsNew().更好的是,只需使用ifnot绑定.

   <tr data-bind="ifnot:IsNew">