/// <summary>
/// 这是初始化的时候使用。
/// </summary>
/// <returns></returns>
public async Task <IEnumerable <Messages> > GetAllMessageAsync()
{
using (CoremvcContext context = new CoremvcContext())
{
return(await context.Messages.ToListAsync());
}
}
/// <summary>
/// 通过EF添加一条数据进去
/// </summary>
/// <param name="message"></param>
/// <returns></returns>
public async Task Add(Messages message)
{
using (CoremvcContext context = new CoremvcContext())
{
context.Messages.Add(message);
await context.SaveChangesAsync();
}
}
public async Task UpdateOne(Messages messages)
{
using (CoremvcContext context = new CoremvcContext())
{
context.Entry(messages).State = EntityState.Modified; //第一种更新的方法
//context.Update(messages); //第二种更新的方法
await context.SaveChangesAsync();
}
}
/// <summary>
/// 删除一条记录
/// </summary>
/// <param name="id">被删除的记录的ID</param>
/// <returns>一条留言</returns>
public async Task DelectOne(int id)
{
using (CoremvcContext context = new CoremvcContext())
{
var TheOne = GetMessagesById(id);
context.Remove(TheOne);
await context.SaveChangesAsync();
}
}
/// <summary>
/// 通过ID去查询
/// </summary>
/// <param name="id">被查找的留言的ID</param>
/// <returns>一条留言</returns>
public Messages GetMessagesById(int id)
{
using (CoremvcContext context = new CoremvcContext())
{
var result = context.Messages.SingleOrDefault(m => m.Id == id);
if (result == null)
{
throw new NotFoundException($"ID为{id}的留言已经找不到了"); //在这里就判断了数据库中有没有，所以其他地方不用再判定了
}
return(result);
}
}