我正在使用asp.net mvc 5,并希望为类Topic
实现3种方法(添加/更新/删除):
class Topic : IDisposable
{
public Topic() { }
private TopicViewModels Model { get; set; }
private string Flag { get; set; }
public void Add(TopicViewModels model)
{
Model = model;
Flag = "Add";
}
public void Update(TopicViewModels model)
{
Model = model;
Flag = "Update";
}
public void Remove(TopicViewModels model)
{
Model = model;
Flag = "Remove";
}
public async Task<int> SaveChangesAsync()
{
using (var db = new MyDbContext())
{
switch (Flag)
{
case "Add":
db.Topics.Add(Model);
break;
case "Update":
var topic = await db.Topics.SingleAsync(x => x.Id == Model.Id);
topic = Model;
break;
case "Remove":
db.Topics.Remove(Model);
break;
}
return await db.SaveChangesAsync();
}
}
public void Dispose()
{
throw new NotImplementedException();
}
}
我的问题:如何声明方法
public virtual TEntity Update(TEntity entity);
课程DbSet<TEntity>
中的?
“更新”时我想要实现的目标:
switch (Flag)
{
case "Update":
db.Topics.Update(Model);
break;
}
我的子问题:还有另一种方法可以在不使用标志的情况下完全调用方法SaveChangesAsync
吗?
答案 0 :(得分:1)
你可以这样做;
public void Update<T>(T entity) where T:class
{
db.Entry<T>(entity).State = EntityState.Modified;
db.SaveChanges();
}