public virtual T FindById(object id)
{
using (var context = new ModernHisContext())
{
return(context.Set <T>().Find(id));
}
}
public IEnumerable <T> FindBySQL(string sql, params object[] sqlParams)
{
using (var context = new ModernHisContext())
{
return(context.Database.SqlQuery <T>(sql, sqlParams).ToList());
}
}
public void Delete(T obj)
{
using (var context = new ModernHisContext())
{
context.Set <T>().Remove(obj);
context.SaveChanges();
}
}
public virtual IEnumerable <T> FindAll()
{
using (var context = new ModernHisContext())
{
return(context.Set <T>()
.Select(p => p)
.ToList());
}
}
public T Save(T obj)
{
using (var context = new ModernHisContext())
{
context.Set <T>().Add(obj);
context.SaveChanges();
return(obj);
}
}
public virtual IEnumerable <V> FindBySelect <V>(Func <T, V> selectExpression)
{
using (var context = new ModernHisContext())
{
return(context.Set <T>()
.Select(selectExpression)
.ToList());
}
}
public virtual IEnumerable <T> FindByLinq(Func <T, bool> expression)
{
using (var context = new ModernHisContext())
{
return(context.Set <T>()
.Where(expression)
.Select(p => p)
.ToList());
}
}
public void DeleteById(object id)
{
using (var context = new ModernHisContext())
{
var obj = context.Set <T>().Find(id);
if (obj != null)
{
context.Set <T>().Remove(obj);
context.SaveChanges();
}
}
}
/// <summary>
/// EF的更新最好的办法就是先查询再修改，不然很麻烦
/// </summary>
/// <param name="obj"></param>
/// <param name="getPkHandler"></param>
public void Update(T obj, Func <T, object> getPkHandler)
{
using (var context = new ModernHisContext())
{
var key = getPkHandler.Invoke(obj);
var oldObj = context.Set <T>().Find(key);
if (oldObj != null)
{
ObjectRefletUtil.SetValue <T>(oldObj, obj);
context.Entry <T>(oldObj).State = EntityState.Modified;
context.SaveChanges();
}
}
}
public void DeleteByLinq(Func <T, bool> whereExpression)
{
using (var context = new ModernHisContext())
{
var objs = context.Set <T>()
.Where(whereExpression)
.Select(p => p);
foreach (var obj in objs)
{
context.Set <T>().Remove(obj);
}
context.SaveChanges();
}
}
private void testTran()
{
//数据库上下文
using (var context = new ModernHisContext())
{
//开启事务
using (var scope = context.Database.BeginTransaction())
{
try
{
//添加一个famousePerson
var famousePerson = new FamousPerson();
context.FamousPersons.Add(famousePerson);
//添加一个historyEvent
var historyEvent = new HistoryEvent();
context.HistoryEvents.Add(historyEvent);
scope.Commit(); //正常完成就可以提交，famousePerson和historyEvent都会添加
}
catch (Exception ex)
{
scope.Rollback(); //发生异常就回滚，famousePerson和historyEvent都不会添加
}
}
}
//数据库上下文
using (var context = new ModernHisContext())
{
//添加一个famousePerson
var famousePerson = new FamousPerson();
context.FamousPersons.Add(famousePerson);
//添加一个historyEvent
var historyEvent = new HistoryEvent();
context.HistoryEvents.Add(historyEvent);
context.SaveChanges(); //savechanges方法会将对数据库的多个封装为一个完整的事务
}
}
