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  • .NET Core如何实现多语言功能？
  • 发布于 2个月前
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多语言也是我们经常能用到的东西，asp.net core中默认支持了多语言，可以使用.resx资源文件来管理多语言配置。但是在修改资源文件后，我们的应用服务无法及时更新，属实麻烦一些。我们可以通过扩展IStringLocalizer，实现我们想要的多语言配置方式，比如Json配置，PO 文件配置，EF数据库配置等等。这里我们选用数据库配置的方式，直接查询数据库的多语言配置进行转换。

创建表实体
多语言管理只需要两个表结构，一个是多语言国家表，一个是多语言资源表。两者是一对多关系。
namespace Wheel.Domain.Localization
{
    public class LocalizationCulture : IEntity<int>
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public virtual List<LocalizationResource> Resources { get; set; }
    }
}
namespace Wheel.Domain.Localization
{
    public class LocalizationResource : IEntity<int>
    {
        // 堆代码 duidaima.com
        public int Id { get; set; }
        public string Key { get; set; }
        public string Value { get; set; }
        public virtual int CultureId { get; set; }
        public virtual LocalizationCulture Culture { get; set; }
    }
}
修改DbContext
添加DbSet和配置表结构：
#region Localization
public DbSet<LocalizationCulture> Cultures { get; set; }
public DbSet<LocalizationResource> Resources { get; set; }
#endregion
protected override void OnModelCreating(ModelBuilder builder)
{
    base.OnModelCreating(builder);

    ConfigureIdentity(builder);
    ConfigureLocalization(builder);
    ConfigurePermissionGrants(builder);
}
void ConfigureLocalization(ModelBuilder builder)
{
    builder.Entity<LocalizationCulture>(b =>
    {
        b.Property(a => a.Id).ValueGeneratedOnAdd();
        b.ToTable("LocalizationCulture"); 
        b.Property(a => a.Name).HasMaxLength(32);
        b.HasMany(a => a.Resources);
    });
    builder.Entity<LocalizationResource>(b =>
    {
        b.Property(a => a.Id).ValueGeneratedOnAdd();
        b.ToTable("LocalizationResource");
        b.HasOne(a => a.Culture);
        b.HasIndex(a => a.CultureId);
        b.Property(a => a.Key).HasMaxLength(256);
        b.Property(a => a.Value).HasMaxLength(1024);
    });
}
然后进行数据库迁移即可生成数据库表结构。

实现EF多语言
这里我们需要实现一下EFStringLocalizerFactory和EFStringLocalizer，使用EFStringLocalizerFactory来创建EFStringLocalizer。
namespace Wheel.Localization
{
    public class EFStringLocalizerFactory : IStringLocalizerFactory, ISingletonDependency
    {
        IServiceProvider _serviceProvider;
        public EFStringLocalizerFactory(IServiceProvider serviceProvider)
        {
            _serviceProvider = serviceProvider;
        }

        public IStringLocalizer Create(Type resourceSource)
        {
            var scope = _serviceProvider.CreateScope();
            var db = scope.ServiceProvider.GetRequiredService<WheelDbContext>();
            var cahce = scope.ServiceProvider.GetRequiredService<IMemoryCache>();
            return new EFStringLocalizer(db, cahce);
        }

        public IStringLocalizer Create(string baseName, string location)
        {
            var scope = _serviceProvider.CreateScope();
            var db = scope.ServiceProvider.GetRequiredService<WheelDbContext>();
            var cahce = scope.ServiceProvider.GetRequiredService<IMemoryCache>();
            return new EFStringLocalizer(db, cahce);
        }
    }
}

namespace Wheel.Localization
{
    public class EFStringLocalizer : IStringLocalizer
    {
        private readonly WheelDbContext _db;
        private readonly IMemoryCache _memoryCache;
        public EFStringLocalizer(WheelDbContext db, IMemoryCache memoryCache)
        {
            _db = db;
            _memoryCache = memoryCache;
        }

        public LocalizedString this[string name]
        {
            get
            {
                var value = GetString(name);
                return new LocalizedString(name, value ?? name, resourceNotFound: value == null);
            }
        }

        public LocalizedString this[string name, params object[] arguments]
        {
            get
            {
                var format = GetString(name);
                var value = string.Format(format ?? name, arguments);
                return new LocalizedString(name, value, resourceNotFound: format == null);
            }
        }

        public IStringLocalizer WithCulture(CultureInfo culture)
        {
            CultureInfo.DefaultThreadCurrentCulture = culture;
            return new EFStringLocalizer(_db, _memoryCache);
        }

        public IEnumerable<LocalizedString> GetAllStrings(bool includeAncestorCultures)
        {
            return _db.Resources
                .Include(r => r.Culture)
                .Where(r => r.Culture.Name == CultureInfo.CurrentCulture.Name)
                .Select(r => new LocalizedString(r.Key, r.Value, r.Value == null));
        }

        private string? GetString(string name)
        {
            if (_memoryCache.TryGetValue<string>($"{CultureInfo.CurrentCulture.Name}:{name}", out var value))
            {
                return value;
            }
            else
            {
                value = _db.Resources
                .Include(r => r.Culture)
                .Where(r => r.Culture.Name == CultureInfo.CurrentCulture.Name)
                .FirstOrDefault(r => r.Key == name)?.Value;
                if (!string.IsNullOrWhiteSpace(value))
                {
                    _memoryCache.Set($"{CultureInfo.CurrentCulture.Name}:{name}", value, TimeSpan.FromMinutes(1));
                }
                return value;
            }
        }
    }

    public class EFStringLocalizer<T> : IStringLocalizer<T>
    {
        private readonly WheelDbContext _db;
        private readonly IMemoryCache _memoryCache;
        public EFStringLocalizer(WheelDbContext db, IMemoryCache memoryCache)
        {
            _db = db;
            _memoryCache = memoryCache;
        }

        public LocalizedString this[string name]
        {
            get
            {
                var value = GetString(name);
                return new LocalizedString(name, value ?? name, resourceNotFound: value == null);
            }
        }

        public LocalizedString this[string name, params object[] arguments]
        {
            get
            {
                var format = GetString(name);
                var value = string.Format(format ?? name, arguments);
                return new LocalizedString(name, value, resourceNotFound: format == null);
            }
        }

        public IStringLocalizer WithCulture(CultureInfo culture)
        {
            CultureInfo.DefaultThreadCurrentCulture = culture;
            return new EFStringLocalizer(_db, _memoryCache);
        }

        public IEnumerable<LocalizedString> GetAllStrings(bool includeAncestorCultures)
        {
            return _db.Resources
                .Include(r => r.Culture)
                .Where(r => r.Culture.Name == CultureInfo.CurrentCulture.Name)
                .Select(r => new LocalizedString(r.Key, r.Value, true));
        }

        private string? GetString(string name)
        {
            if (_memoryCache.TryGetValue<string>($"{CultureInfo.CurrentCulture.Name}:{name}", out var value))
            {
                return value;
            }
            else
            {
                value = _db.Resources
                .Include(r => r.Culture)
                .Where(r => r.Culture.Name == CultureInfo.CurrentCulture.Name)
                .FirstOrDefault(r => r.Key == name)?.Value;
                if (!string.IsNullOrWhiteSpace(value))
                {
                    _memoryCache.Set($"{CultureInfo.CurrentCulture.Name}:{name}", value, TimeSpan.FromMinutes(1));
                }
                return value;
            }
        }
    }
}
这里的GetString方法，我们先通过缓存查询多语言内容，若查询不到再进数据库查询，减少数据库的并发量。
多语言国家编码直接使用CultureInfo.CurrentCulture.Name获取。无需传参配置。


启用多语言
再Program中添加多语言代码：
builder.Services.AddLocalization(options => options.ResourcesPath = "Resources");

app.UseRequestLocalization(new RequestLocalizationOptions
{
    ApplyCurrentCultureToResponseHeaders = true,
    DefaultRequestCulture = new RequestCulture("zh-CN"),
    SupportedCultures = new List<CultureInfo>
            {
                new CultureInfo("en"),
                new CultureInfo("zh-CN"),
            },
    SupportedUICultures = new List<CultureInfo>
            {
                new CultureInfo("en"),
                new CultureInfo("zh-CN"),
            }
});
这里配置默认语言是中文，同时支持英文和中文两种。

多语言管理API实现
接下来我们实现LocalizationManage
ILocalizationManageAppService:

namespace Wheel.Services.LocalizationManage
{
    public interface ILocalizationManageAppService : ITransientDependency
    {
        Task<R<LocalizationCultureDto>> GetLocalizationCultureAsync(int id);
        Task<Page<LocalizationCultureDto>> GetLocalizationCulturePageListAsync(PageRequest input);
        Task<R<LocalizationCultureDto>> CreateLocalizationCultureAsync(CreateLocalizationCultureDto input);
        Task<R> DeleteLocalizationCultureAsync(int id);
        Task<R<LocalizationResourceDto>> CreateLocalizationResourceAsync(CreateLocalizationResourceDto input);
        Task<R> UpdateLocalizationResourceAsync(UpdateLocalizationResourceDto input);
        Task<R> DeleteLocalizationResourceAsync(int id);
    }
}
LocalizationManageAppService:


namespace Wheel.Services.LocalizationManage
{
    /// <summary>
    /// 堆代码 duidaima.com
    /// 多语言管理
    /// </summary>
    public class LocalizationManageAppService : WheelServiceBase, ILocalizationManageAppService
    {
        private readonly IBasicRepository<LocalizationCulture, int> _localizationCultureRepository;
        private readonly IBasicRepository<LocalizationResource, int> _localizationResourceRepository;

        public LocalizationManageAppService(IBasicRepository<LocalizationCulture, int> localizationCultureRepository, IBasicRepository<LocalizationResource, int> localizationResourceRepository)
        {
            _localizationCultureRepository = localizationCultureRepository;
            _localizationResourceRepository = localizationResourceRepository;
        }
        /// <summary>
        /// 获取地区多语言详情
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public async Task<R<LocalizationCultureDto>> GetLocalizationCultureAsync(int id)
        {
            var entity = await _localizationCultureRepository.FindAsync(id);

            return new R<LocalizationCultureDto>(Mapper.Map<LocalizationCultureDto>(entity));
        }
        /// <summary>
        /// 分页获取地区多语言列表
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public async Task<Page<LocalizationCultureDto>> GetLocalizationCulturePageListAsync(PageRequest input)
        {
            var (entities, total) = await _localizationCultureRepository
                .GetPageListAsync(a => true,
                (input.PageIndex - 1) * input.PageSize,
                input.PageSize,
                propertySelectors: a => a.Resources
                );

            return new Page<LocalizationCultureDto>(Mapper.Map<List<LocalizationCultureDto>>(entities), total);
        }
        /// <summary>
        /// 创建地区多语言
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public async Task<R<LocalizationCultureDto>> CreateLocalizationCultureAsync(CreateLocalizationCultureDto input)
        {
            var entity = Mapper.Map<LocalizationCulture>(input);
            entity = await _localizationCultureRepository.InsertAsync(entity);
            await UnitOfWork.SaveChangesAsync();
            return new R<LocalizationCultureDto>(Mapper.Map<LocalizationCultureDto>(entity));
        }
        /// <summary>
        /// 删除地区多语言
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public async Task<R> DeleteLocalizationCultureAsync(int id)
        {
            await _localizationCultureRepository.DeleteAsync(id);
            await UnitOfWork.SaveChangesAsync();
            return new R();
        }
        /// <summary>
        /// 创建多语言资源
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public async Task<R<LocalizationResourceDto>> CreateLocalizationResourceAsync(CreateLocalizationResourceDto input)
        {
            var entity = Mapper.Map<LocalizationResource>(input);
            entity = await _localizationResourceRepository.InsertAsync(entity);
            await UnitOfWork.SaveChangesAsync();
            return new R<LocalizationResourceDto>(Mapper.Map<LocalizationResourceDto>(entity));
        }
        /// <summary>
        /// 修改多语言资源
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public async Task<R> UpdateLocalizationResourceAsync(UpdateLocalizationResourceDto input)
        {
            await _localizationResourceRepository.UpdateAsync(a => a.Id == input.Id,
                a => a.SetProperty(b => b.Key, b => input.Key).SetProperty(b => b.Value, b => input.Value));
            await UnitOfWork.SaveChangesAsync();
            return new R();
        }
        /// <summary>
        /// 删除多语言资源
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public async Task<R> DeleteLocalizationResourceAsync(int id)
        {
            await _localizationResourceRepository.DeleteAsync(id);
            await UnitOfWork.SaveChangesAsync();
            return new R();
        }
    }
}
这里包含了多语言的CURD的实现
LocalizationManageController:

namespace Wheel.Controllers
{
    /// <summary>
    /// 多语言管理
    /// </summary>
    [Route("api/[controller]")]
    [ApiController]
    public class LocalizationManageController : WheelControllerBase
    {
        private readonly ILocalizationManageAppService _localizationManageAppService;

        public LocalizationManageController(ILocalizationManageAppService localizationManageAppService)
        {
            _localizationManageAppService = localizationManageAppService;
        }

        /// <summary>
        /// 获取地区多语言详情
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        [HttpGet("Culture/{id}")]
        public async Task<R<LocalizationCultureDto>> GetCulture(int id)
        {
            return await _localizationManageAppService.GetLocalizationCultureAsync(id);
        }
        /// <summary>
        /// 创建地区多语言
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        [HttpPost("Culture")]
        public async Task<R<LocalizationCultureDto>> CreateCulture(CreateLocalizationCultureDto input)
        {
            return await _localizationManageAppService.CreateLocalizationCultureAsync(input);
        }
        /// <summary>
        /// 删除地区多语言
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        [HttpDelete("Culture/{id}")]
        public async Task<R> DeleteCulture(int id)
        {
            return await _localizationManageAppService.DeleteLocalizationCultureAsync(id);
        }
        /// <summary>
        /// 分页获取地区多语言列表
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        [HttpGet("Culture")]
        public async Task<Page<LocalizationCultureDto>> GetCulturePageList([FromQuery]PageRequest input)
        {
            return await _localizationManageAppService.GetLocalizationCulturePageListAsync(input);
        }
        /// <summary>
        /// 创建多语言资源
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        [HttpPost("Resource")]
        public async Task<R<LocalizationResourceDto>> CreateResource(CreateLocalizationResourceDto input)
        {
            return await _localizationManageAppService.CreateLocalizationResourceAsync(input);
        }
        /// <summary>
        /// 修改多语言资源
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        [HttpPut("Resource")]
        public async Task<R> UpdateResource(UpdateLocalizationResourceDto input)
        {
            return await _localizationManageAppService.UpdateLocalizationResourceAsync(input);
        }
        /// <summary>
        /// 删除多语言资源
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        [HttpDelete("Resource/{id}")]
        public async Task<R> DeleteResource(int id)
        {
            return await _localizationManageAppService.DeleteLocalizationResourceAsync(id);
        }
        /// <summary>
        /// 获取多语言资源列表
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        [HttpGet("Resources")]
        [AllowAnonymous]
        public Task<R<Dictionary<string, string>>> GetResources()
        {
            var resources = L.GetAllStrings().ToDictionary(a=>a.Name, a=>a.Value);
            return Task.FromResult(new R<Dictionary<string, string>>(resources));
        }
    }
}
在控制器额外添加一个匿名访问的API，GetResources()用于客户端集成多语言配置。L是IStringLocalizer实例。

启用服务测试一下。

可以看到成功获取英文和中文的多语言列表。
就这样我们完成多语言管理的实现。
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