带有类型参数的页面 [英] Page with type parameter

问题描述

我想使用UWP的新功能-> x:Bind.为此，我所有的页面都需要具有ViewModel属性(如教程中所述).为了避免代码重复，我建立了如下基类:

I would like to use new feature of UWP -> x:Bind. In order to that, all my pages need to have ViewModel property (as described in tutorials). To avoid code duplicity, I have established base class as follows:

public abstract class BasePage<TBaseVM> : Page, where TBaseVM : BaseVM
{
    public TBaseVM VM { get; private set; }

    protected BasePage()
    {
        DataContextChanged += (s, e) => VM = e.NewValue as TBaseVM;            
    }
}

如您所见，此BasePage类包含名为"VM"的属性，并且该属性的类型为BaseVM.因此，我不需要在每个派生类上定义VM属性.

As you can see this BasePage class contains property called "VM" and property is of type BaseVM. Hence, I don't need to define VM property on each derived class.

然后我创建了在xaml中定义的派生页面'MainPage'，如下所示:

Then I created derived page 'MainPage' defined in xaml as follows:

<pages:BasePage
x:Class="Realarm.View.Pages.MainPage"
x:TypeArguments="viewModel:MainVM">

这样做，即使Resharper的Intellisense也可以通过MainPage.xaml中的"MainVM"为我提供属性，因此可以编写:

By doing that, even Resharper's Intellisense offers me properties from "MainVM" in MainPage.xaml, thus is can write:

<ListView ItemsSource="{x:Bind VM.AlarmsVM}">

不幸的是，当我尝试构建项目时，在MainPage.g.i.cs中出现错误:

Unfortunately, when I try to build the project, I get error in MainPage.g.i.cs:

严重性代码描述项目文件行错误CS0305使用通用类型'BasePage'需要1个类型参数Realarm D:... \ Realarm \ obj \ x86 \ Debug \ View \ Pages \ MainPage.g.i.cs 13

Severity Code Description Project File Line Error CS0305 Using the generic type 'BasePage' requires 1 type arguments Realarm D:...\Realarm\obj\x86\Debug\View\Pages\MainPage.g.i.cs 13

有帮助吗?

推荐答案

我使用Xamarin.Forms进行了这项工作.

I got this working using Xamarin.Forms.

基本页面:

public abstract class BaseContentPage<TViewModel> : ContentPage where TViewModel : BaseViewModel, new()

HomePage.cs:

HomePage.cs:

public partial class HomePage : BaseContentPage<HomeViewModel>

HomePage.xaml:

HomePage.xaml:

<d:BaseContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:d="clr-namespace:Sample.Pages;assembly=Sample" xmlns:vm="clr-namespace:Sample.ViewModels;assembly=Sample" x:Class="Sample.Pages.HomePage" x:TypeArguments="vm:HomeViewModel">
<ContentPage.Content>
</ContentPage.Content>

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