将Abp移植进.NET MAUI项目（二）：配置与基类编写

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因为我们要做一个数据持久化型的小应用，所以在完成Abp功能的集成后，我们需要做数据库相关的配置工作

配置数据库

在MauiBoilerplate.Core项目中，添加两个实体类：

我们简单的写一个歌曲（song）的实体类

其中包含了歌曲标题（MusicTitle），艺术家（Artist），专辑（Album），时长（Duration）以及发售日期（ReleaseDate）

    public class Song : FullAuditedEntity<long>
    {
        [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public override long Id { get; set; }

        public string MusicTitle { get; set; }

        public string Artist { get; set; }

        public string Album { get; set; }

        public TimeSpan Duration { get; set; }

        public DateTime ReleaseDate { get; set; }

    }

在MauiBoilerplate.EntityFrameworkCore项目中：将这个类添加至MauiBoilerplateDbContext中

public class MauiBoilerplateDbContext : AbpDbContext
{
     //Add DbSet properties for your entities...
     public DbSet<Song> Song { get; set; }
}

新建WithDbContextHelper.cs

创建一个静态类WithDbContext，利用Abp的工作单元模式对dbcontext执行操作

    public class WithDbContextHelper
    {
        public static void WithDbContext<TDbContext>(IIocResolver iocResolver, Action<TDbContext> contextAction)
    where TDbContext : DbContext
        {
            using (var uowManager = iocResolver.ResolveAsDisposable<IUnitOfWorkManager>())
            {
                using (var uow = uowManager.Object.Begin(TransactionScopeOption.Suppress))
                {
                    var context = uowManager.Object.Current.GetDbContext<TDbContext>();

                    contextAction(context);

                    uow.Complete();
                }
            }
        }

    }

[可选]种子数据相关类编写

编写种子数据帮助类SeedHelper.cs，与数据库初始化类InitialDbBuilder，这里将在程序启动时向数据库插入一些种子数据

    public static class SeedHelper
    {
        public static void SeedHostDb(IIocResolver iocResolver)
        {
            Helper.WithDbContextHelper.WithDbContext<MauiBoilerplateDbContext>(iocResolver, SeedHostDb);
        }

        public static void SeedHostDb(MauiBoilerplateDbContext context)
        {
            context.SuppressAutoSetTenantId = true;

            // Host seed
            new InitialDbBuilder(context).Create();
        }

    }

编写MauiBoilerplateEntityFrameworkCoreModule.cs

    [DependsOn(
        typeof(MauiBoilerplateCoreModule),
        typeof(AbpEntityFrameworkCoreModule))]
    public class MauiBoilerplateEntityFrameworkCoreModule : AbpModule
    {
        public bool SkipDbContextRegistration { get; set; }

        public bool SkipDbSeed { get; set; }

        public override void PreInitialize()
        {
            if (!SkipDbContextRegistration)
            {
                Configuration.Modules.AbpEfCore().AddDbContext<MauiBoilerplateDbContext>(options =>
                {
                    if (options.ExistingConnection != null)
                    {
                        DbContextOptionsConfigurer.Configure(options.DbContextOptions, options.ExistingConnection);
                    }
                    else
                    {
                        DbContextOptionsConfigurer.Configure(options.DbContextOptions, options.ConnectionString);
                    }
                });
            }
        }
        public override void Initialize()
        {

            IocManager.RegisterAssemblyByConvention(typeof(MauiBoilerplateEntityFrameworkCoreModule).GetAssembly());

        }

        public override void PostInitialize()
        {
            Helper.WithDbContextHelper.WithDbContext<MauiBoilerplateDbContext>(IocManager, RunMigrate);
            if (!SkipDbSeed)
            {
                SeedHelper.SeedHostDb(IocManager);
            }
        }

        public static void RunMigrate(MauiBoilerplateDbContext dbContext)
        {
            dbContext.Database.Migrate();
        }

    }

将MauiBoilerplate.EntityFrameworkCore设置为启动项目，选择框架为.net6.0

打开程序包管理器控制台，选择默认项目MauiBoilerplate.EntityFrameworkCore

​编辑

运行Add-Migration命令，将生成迁移脚本

运行MauiBoilerplate.EntityFrameworkCore，将生成mato.db等三个文件，

​编辑

编写基类（可选）

我们在使用相关的父类时，某某ContentPage，或者某某UserControl时，需要像使用AbpServiceBase一样使用一些常用的功能，比如字符串的本地化，配置，AutoMapper对象等，就像AbpServiceBase的注释里描述的那样：

/// <summary>

    /// This class can be used as a base class for services.

    /// It has some useful objects property-injected and has some basic methods

    /// most of services may need to.

    /// </summary>

此时，需要编写一个基类（奈何.net本身没有Mixin模式，C#语言也不支持多继承），这些基类仅是注入了一些常用的Manager，方便代码编写者使用，因此基类的创建不是必须的。

比如可以增加一个ContentPageBase类作为ContentPage实例控件的基类

新建ContentPageBase.cs文件，创建类ContentPageBase继承于ContentPage

    public class ContentPageBase : ContentPage
    {
        public IObjectMapper ObjectMapper { get; set; }

        /// <summary>
        /// Reference to the setting manager.
        /// </summary>
        public ISettingManager SettingManager { get; set; }

        /// <summary>
        /// Reference to the localization manager.
        /// </summary>
        public ILocalizationManager LocalizationManager { get; set; }

        /// <summary>
        /// Gets/sets name of the localization source that is used in this application service.
        /// It must be set in order to use <see cref="L(string)"/> and <see cref="L(string,CultureInfo)"/> methods.
        /// </summary>
        protected string LocalizationSourceName { get; set; }

        /// <summary>
        /// Gets localization source.
        /// It's valid if <see cref="LocalizationSourceName"/> is set.
        /// </summary>
        protected ILocalizationSource LocalizationSource
        {
            get
            {
                if (LocalizationSourceName == null)
                {
                    throw new AbpException("Must set LocalizationSourceName before, in order to get LocalizationSource");
                }

                if (_localizationSource == null || _localizationSource.Name != LocalizationSourceName)
                {
                    _localizationSource = LocalizationManager.GetSource(LocalizationSourceName);
                }

                return _localizationSource;
            }
        }
        private ILocalizationSource _localizationSource;

        /// <summary>
        /// Constructor.
        /// </summary>
        protected ContentPageBase()
        {
            LocalizationSourceName = MauiBoilerplateConsts.LocalizationSourceName;
            ObjectMapper = NullObjectMapper.Instance;
            LocalizationManager = NullLocalizationManager.Instance;
        }

        /// <summary>
        /// Gets localized string for given key name and current language.
        /// </summary>
        /// <param name="name">Key name</param>
        /// <returns>Localized string</returns>
        protected virtual string L(string name)
        {
            return LocalizationSource.GetString(name);
        }

        /// <summary>
        /// Gets localized string for given key name and current language with formatting strings.
        /// </summary>
        /// <param name="name">Key name</param>
        /// <param name="args">Format arguments</param>
        /// <returns>Localized string</returns>
        protected virtual string L(string name, params object[] args)
        {
            return LocalizationSource.GetString(name, args);
        }

        /// <summary>
        /// Gets localized string for given key name and specified culture information.
        /// </summary>
        /// <param name="name">Key name</param>
        /// <param name="culture">culture information</param>
        /// <returns>Localized string</returns>
        protected virtual string L(string name, CultureInfo culture)
        {
            return LocalizationSource.GetString(name, culture);
        }

        /// <summary>
        /// Gets localized string for given key name and current language with formatting strings.
        /// </summary>
        /// <param name="name">Key name</param>
        /// <param name="culture">culture information</param>
        /// <param name="args">Format arguments</param>
        /// <returns>Localized string</returns>
        protected virtual string L(string name, CultureInfo culture, params object[] args)
        {
            return LocalizationSource.GetString(name, culture, args);
        }
    }

同理，若我们使用了其他控件类时，可以增加一个Base类作为实例控件的基类的

比如Popup控件，就编写一个PopupBase基类。

在这里我们编写了两个基类

​编辑

本地化配置

新建一个TranslateExtension.cs作为Xaml标签的本地化处理类

    [ContentProperty("Text")]
    public class TranslateExtension : DomainService, IMarkupExtension
    {
        public TranslateExtension()
        {
            LocalizationSourceName = MauiBoilerplateConsts.LocalizationSourceName;

        }
        public string Text { get; set; }

        public object ProvideValue(IServiceProvider serviceProvider)
        {
            if (Text == null)
                return "";
            var translation = L(Text);
            return translation;
        }

    }

在MauiBoilerplateLocalization.cs配置好SourceFiles

    public static void Configure(ILocalizationConfiguration localizationConfiguration)
        {
            localizationConfiguration.Sources.Add(
                new DictionaryBasedLocalizationSource(MauiBoilerplateConsts.LocalizationSourceName,
                    new XmlEmbeddedFileLocalizationDictionaryProvider(
                        typeof(LocalizationConfigurer).GetAssembly(),
                        "MauiBoilerplate.Core.Localization.SourceFiles"
                    )
                )
            );
        }

编写ViewModelBase

为实现Mvvm设计模式，页面需要绑定一个继承于ViewModelBase的类型

在ViewModelBase中，需要实现INotifyPropertyChanged以处理绑定成员变化时候的通知消息；

ViewModelBase集成于AbpServiceBase以方便ViewModel代码编写者使用常用的功能，比如字符串的本地化，配置，AutoMapper对象等。

    public abstract class ViewModelBase : AbpServiceBase, ISingletonDependency, INotifyPropertyChanged
    {
        public ViewModelBase()
        {
            LocalizationSourceName = MauiBoilerplateConsts.LocalizationSourceName;
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected PropertyChangedEventHandler PropertyChangedHandler { get; }

        public void VerifyPropertyName(string propertyName)
        {
            Type type = GetType();
            if (!string.IsNullOrEmpty(propertyName) && type.GetTypeInfo().GetDeclaredProperty(propertyName) == null)
                throw new ArgumentException("找不到属性", propertyName);
        }

        public virtual void RaisePropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChangedEventHandler propertyChanged = PropertyChanged;
            if (propertyChanged == null)
                return;
            propertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }

        public virtual void RaisePropertyChanged<T>(Expression<Func<T>> propertyExpression)
        {
            if (PropertyChanged == null)
                return;
            string propertyName = GetPropertyName(propertyExpression);
            if (string.IsNullOrEmpty(propertyName))
                return;
            RaisePropertyChanged(propertyName);
        }

        protected static string GetPropertyName<T>(Expression<Func<T>> propertyExpression)
        {
            if (propertyExpression == null)
                throw new ArgumentNullException(nameof(propertyExpression));
            MemberExpression body = propertyExpression.Body as MemberExpression;
            if (body == null)
                throw new ArgumentException("参数不合法", nameof(propertyExpression));
            PropertyInfo member = body.Member as PropertyInfo;
            if (member == null)
                throw new ArgumentException("找不到属性", nameof(propertyExpression));
            return member.Name;
        }

    }

至此，我们完成了数据库的配置，内容页基类与 ViewModel基类的编写，接下来可以制作我们的页面了。请看下一章将Abp移植进.NET MAUI项目（三）：构建UI层 - 林晓lx - 博客园 (cnblogs.com)

项目地址

jevonsflash/maui-abp-sample (github.com)

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