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Question

我有一个班级UserManagement，并且总是希望得到相同的instance（就像单身模式一样）。所以现在我的问题是，我总是得到一个名为“Singleton”的新instance内容。我是StructureMap的新手。我已尝试在网站上描述的两个版本（http://structuremap.github.io/object-lifecycle/）（http://structuremap.github.io/glossary/）。

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        Container container = new Container(new UserManagement());

        //UserManagement instance = container.GetInstance<UserManagement>("Singleton");
        UserManagement instance = container.GetInstance<UserManagement>();
        MessageBox.Show(instance.Test);
    }
}

public interface IUser
{
    void DoSomethingFancy();
}

public class User : IUser
{
    public void DoSomethingFancy()
    {

    }
}

public interface IDatabase
{
    void DoSomething();
}

public class Database : IDatabase
{
    public void DoSomething()
    {

    }
}

public class UserManagement : Registry
{
    public string Test;

    private Container _Container;
    private IUser _User;
    private IDatabase _Database;

    public UserManagement()
    {
        _Container = new Container(_ =>
        {
            _.For<IUser>().Use<User>();
            _.For<IDatabase>().Use<Database>();
        });

        _User = _Container.GetInstance<IUser>();
        _Database = _Container.GetInstance<IDatabase>();

        Test = DateTime.Now.ToString();

        //For<UserManagement>().AddInstances(x =>
        //{
        //    x.Type<UserManagement>().Named("Singleton");
        //});

        For<UserManagement>().Singleton();
    }
}

更新

我的解决方案有3个项目

BootstrapperLibrary（类库 - Bootstrapper）
Gui（ WpfApp - MainWindow.xaml）
框架（类库 - LoginAction - UserManagement）

BootstrapperLibrary

Bootstrapper.cs

public static class Bootstrapper
{
    public static Container Container => _Container ?? (_Container = InitializeContainer());
    private static Container _Container;

    public static Func<Container> InitializeContainer;    
}

桂

App.xaml.cs

public partial class App : Application
{
    public App()
    {
        Bootstrapper.InitializeContainer += InitializeContainer;
    }

    private Container InitializeContainer()
    {
        Container container = new Container(c => c.Scan(scanner =>
        {
            scanner.TheCallingAssembly();
            scanner.WithDefaultConventions();
            scanner.AssembliesFromApplicationBaseDirectory();
        }));
        container.Configure(c =>
            {
                c.ForSingletonOf<UserManagement>();
                c.For<IUser>().Use<UserAdv>();
            }
        );

        return container;
    }
}

MainWindow.xaml

<Window x:Class="Gui.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
        xmlns:myFramework="clr-namespace:MyFramework;assembly=MyFramework"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Button Content="Button" HorizontalAlignment="Left" Margin="383,228,0,0" VerticalAlignment="Top" Width="75">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="Click">
                    <myFramework:LoginAction/>
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </Button>

    </Grid>
</Window>

框架

LoginAction.cs

public class LoginAction : TriggerAction<DependencyObject>
{
    protected override void Invoke(object parameter)
    {
        UserManagement userManagement = Bootstrapper.Container.GetInstance<UserManagement>();
        Console.WriteLine(userManagement.Test); //Just to see if it's still the same instance who holds for example the current user.
    }
}

UserManagement.cs

public interface IUser
{
    string Name { get; }
    void DoSomethingFancy();
}

public class User : IUser
{
    public string Name { get; } = "default";

    public void DoSomethingFancy()
    {

    }
}

public class UserAdv : IUser
{
    public string Name { get; } = "Advanced";

    public void DoSomethingFancy()
    {

    }
}

public interface IDatabase
{
    void DoSomething();
}

public class Database : IDatabase
{
    public void DoSomething()
    {

    }
}

public class UserManagement
{
    public string Test;

    public IUser User;
    private IDatabase _Database;

    public UserManagement(IUser user, IDatabase database)
    {
        User = user;
        _Database = database;

        Test = DateTime.Now.ToString();
    }
}

如果我理解正确，我的主应用程序现在会初始化并配置Container中的application startup。 Bootstrapper类在那里持有一个静态实例。 MyFramework从静态UserManangement实例中提取Container的实例。

这是如何使用StructureMap的正确方法吗？感谢您的耐心等待！

Answer 1

您应该声明：

ForConcreteType<UserManagement>().Singleton();

修改

您可以在程序启动期间实现一个bootstrapper类并调用Initialize()方法：

public sealed class Bootstrapper { private static StructureMap.Container _container; public StructureMap.Container MyContainer { get { return _container; } } static Bootstrapper() { } public static Initialize() { StructureMap.Configuration.DSL.Registry registry = new StructureMap.Configuration.DSL.Registry(); registry.For<IUser>().Use<User>(); registry.For<IDatabase>().Use<Database>(); registry.ForConcreteType<UserManagement>().Singleton(); _container = new Container(registry); } }

从UserManagement类中删除容器初始化，让DI框架注入具体的类型/对象。

public class UserManagement { public string Test; private IUser _user; private IDatabase _database; public UserManagement(IUser user, IDatabase database) { _user = user; _database = database; Test = DateTime.Now.ToString(); } }

修改WPF测试窗口：

public partial class MainWindow : Window { static MainWindow() { // only for demonstration!!! Bootstrapper.Initialize(); } public MainWindow() { InitializeComponent(); } private void Button_Click(object sender, RoutedEventArgs e) { Container container = Bootstrapper.MyContainer; UserManagement instance = container.GetInstance<UserManagement>(); MessageBox.Show(instance.Test); } }

结构图|如何创建单例实例/获取始终相同的实例

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