Xamarin MVVM Light ViewModelLocator在xaml中設置BindingContext

Question

我想通過xaml而不是后端代碼設置BindingContext。 目前我正在分配這樣的：

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();
        BindingContext = App.Locator.Main;
    }
}

如何通過Xaml協助BindingContext？ 我試過這樣的：

LoginPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="Codesign.DtpMobilePortable.Views.LoginPage" BindingContext="{Binding LoginPage, Source={StaticResource ViewModelLocator}}"> 
  <StackLayout Spacing="20" Padding="50" VerticalOptions="Center">

    <Entry x:Name = "EntryUsername" Text="{Binding EntryUsernameText}" Placeholder = "Username"/>  
    <Entry x:Name = "EntryPassword" Text="{Binding EntryPasswordText}" Placeholder = "Password" IsPassword = "true"   />

    <Button x:Name = "ButtonLogin"
                        Text = "{Binding LoginButtonText}"
                        TextColor = "White"
                        BackgroundColor = "{Binding LoginButtonColor}" Command="{Binding LoginCommand}"/>    
  </StackLayout>
</ContentPage>

App.xaml中

<?xml version="1.0" encoding="utf-8" ?>
<Application xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:viewModels="clr-namespace:Codesign.DtpMobilePortable.ViewModels;assembly=Codesign.DtpMobilePortable"
             x:Class="Codesign.DtpMobilePortable.Views.App">
<Application.Resources>
    <viewModels:ViewModelLocator
        x:Key="ViewModelLocator" />
</Application.Resources>
</Application>

但我得到關於StaticResource不存在的錯誤。

Answer 1

您應在頁眉上定義StaticResources名稱空間。

這樣的事情：

<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         xmlns:local="clr-namespace:Codesign.DtpMobilePortable;assembly=Codesign.DtpMobilePortable"
         xmlns:Vm="clr-namespace:Codesign.DtpMobilePortable.ViewModel;assembly=Codesign.DtpMobilePortable"
         x:Class="Codesign.DtpMobilePortable.Views.LoginPage"
         BindingContext="{Binding LoginPage, Source={StaticResource ViewModelLocator}}"

在我的示例代碼中，我的StaticResources是在上面的xmlnss:local命名空間中定義的。