c# - 使用反射和泛型方法转换泛型实体

Question

我有一个名为 RevertChanges 的方法看起来像下面这样:

public static void RevertChanges<TEntity>()
{
            var jsonData = DataAccess.GetEnvironmentJson((int)Environments.Production);
            var model = JsonConvert.DeserializeObject<Models.FullDataSetModel>(jsonData);
            var targetEntity = typeof(TEntity).Name;
            using (var db = new LoginPageContentEntities())
            {
                db.Database.ExecuteSqlCommand(String.Format("TRUNCATE TABLE [{0}]", targetEntity));
                var modelValue = model.GetType().GetProperty(targetEntity).GetValue(model, null);
                var table = (DbSet)(typeof(LoginPageContentEntities).GetProperty(targetEntity).GetValue(db, null));
                table.AddRange((DbSet)modelValue);                         
                db.SaveChanges();
            }
}

我知道无论TEntity is 将匹配 modelValue 数据集。 DbSet 转换不起作用，我正在努力寻找如何使用泛型返回整个实体。我发现如果我用 (IEnumerable<TEntity>) 转换我可以调用ToList()在 table 上，但是这不起作用，因为我需要能够调用添加范围。是否可以:

1. 返回带有泛型的实体引用？
2. 访问AddRange进而保存上下文？

对于上下文，我正在尝试替换此方法:

public static void RevertChanges(Environments targetToRestoreFrom, ContentFields tableToRevert)
        {
            var jsonData = DataAccess.GetEnvironmentJson((int)targetToRestoreFrom);
            var model = JsonConvert.DeserializeObject<Models.FullDataSetModel>(jsonData);            
            using (var db = new LoginPageContentEntities())
            {
                switch (tableToRevert)
                {
                    case ContentFields.ProductInformation:
                        db.Database.ExecuteSqlCommand("TRUNCATE TABLE [ProductInformation]");
                        db.ProductInformation.AddRange(model.ProductInformation);
                        break;
                    case ContentFields.DidYouKnow:
                        db.Database.ExecuteSqlCommand("TRUNCATE TABLE [DidYouKnow]");
                        db.DidYouKnow.AddRange(model.DidYouKnow);
                        break;
                    case ContentFields.MaintenanceMessage:
                        db.Database.ExecuteSqlCommand("TRUNCATE TABLE [MaintenanceMessage]");
                        db.MaintenanceMessage.AddRange(model.MaintenanceMessage);
                        break;
                    case ContentFields.TrainingEvent:
                        db.Database.ExecuteSqlCommand("TRUNCATE TABLE [TrainingEvents]");
                        db.TrainingEvents.AddRange(model.TrainingEvents);
                        break;
                    case ContentFields.VideoContent:
                        db.Database.ExecuteSqlCommand("TRUNCATE TABLE [HtmlSnippets]");
                        db.HtmlSnippets.AddRange(model.HtmlSnippets);
                        break;
                    case ContentFields.ProductMarketingUrl:
                        db.Database.ExecuteSqlCommand("TRUNCATE TABLE [ProductMarketingUrl]");
                        db.ProductMarketingUrl.AddRange(model.ProductMarketingUrl);
                        break;
                }                
                db.SaveChanges();
            }
        }

型号:

namespace LoginPageContentManager.Models
{
    public class FullDataSetModel
    {
        public List<DidYouKnow> DidYouKnow                   { get; set; }
        public List<HtmlSnippets> HtmlSnippets               { get; set; }
        public List<MaintenanceMessage> MaintenanceMessage   { get; set; }
        public List<ProductInformation> ProductInformation   { get; set; }
        public List<TrainingEvents> TrainingEvents           { get; set; }
        public List<ProductMarketingUrl> ProductMarketingUrl { get; set; }
    }
}

Answer 1

Set<T> 方法允许您获得 DbSet一般而言。

在您的情况下，您应该能够通过执行以下操作添加到集合中:

db.Set<TEntity>().AddRange(modelValue)