c# - Xamarin MVVM Light ViewModelLocator 在 xaml 中设置 BindingContext

Question

我想通过 xaml 而不是后端代码设置 BindingContext。目前我是这样分配的:

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

如何通过 Xaml 分配 BindingContext？我试过这样:

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>

应用程序.xaml

<?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>

但是我收到有关 StaticResource 不存在的错误。

Answer 1

您应定义 StaticResources页面标题上的 namespace 。

类似的东西:

<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}}"

在我的示例代码中我的 StaticResources在 xmlnss:local 上定义上面的命名空间。