我在实体框架中有一个名为雇佣的SQL Server表,其中有一个名为ID的键列。
如何使用实体框架从表中删除单个记录?
我在实体框架中有一个名为雇佣的SQL Server表,其中有一个名为ID的键列。
如何使用实体框架从表中删除单个记录?
当前回答
更普通的approuch
public virtual void Delete<T>(int id) where T : BaseEntity, new()
{
T instance = Activator.CreateInstance<T>();
instance.Id = id;
if (dbContext.Entry<T>(entity).State == EntityState.Detached)
{
dbContext.Set<T>().Attach(entity);
}
dbContext.Set<T>().Remove(entity);
}
其他回答
不需要先查询对象,可以通过它的id将它附加到上下文。 是这样的:
var employer = new Employ { Id = 1 };
ctx.Employ.Attach(employer);
ctx.Employ.Remove(employer);
ctx.SaveChanges();
或者,你可以将附加条目的状态设置为已删除:
var employer = new Employ { Id = 1 };
ctx.Entry(employer).State = EntityState.Deleted;
ctx.SaveChanges();
这里有一个安全的方法:
using (var transitron = ctx.Database.BeginTransaction())
{
try
{
var employer = new Employ { Id = 1 };
ctx.Entry(employer).State = EntityState.Deleted;
ctx.SaveChanges();
transitron.Commit();
}
catch (Exception ex)
{
transitron.Rollback();
//capture exception like: entity does not exist, Id property does not exist, etc...
}
}
在这里,您可以堆积您想要的所有更改,因此您可以在SaveChanges和Commit之前执行一系列删除操作,因此只有当它们都成功时才会应用它们。
[HttpPost]
public JsonResult DeleteCotnact(int id)
{
using (MycasedbEntities dbde = new MycasedbEntities())
{
Contact rowcontact = (from c in dbde.Contact
where c.Id == id
select c).FirstOrDefault();
dbde.Contact.Remove(rowcontact);
dbde.SaveChanges();
return Json(id);
}
}
你觉得这个简单与否,你也可以试试这个:
var productrow = cnn.Product.Find(id);
cnn.Product.Remove(productrow);
cnn.SaveChanges();
你可以像这样简单地做
public ActionResult Delete(int? id)
{
using (var db = new RegistrationEntities())
{
Models.RegisterTable Obj = new Models.RegisterTable();
Registration.DAL.RegisterDbTable personalDetail = db.RegisterDbTable.Find(id);
if (personalDetail == null)
{
return HttpNotFound();
}
else
{
Obj.UserID = personalDetail.UserID;
Obj.FirstName = personalDetail.FName;
Obj.LastName = personalDetail.LName;
Obj.City = personalDetail.City;
}
return View(Obj);
}
}
[HttpPost, ActionName("Delete")]
public ActionResult DeleteConfirmed(int? id)
{
using (var db = new RegistrationEntities())
{
Registration.DAL.RegisterDbTable personalDetail = db.RegisterDbTable.Find(id);
db.RegisterDbTable.Remove(personalDetail);
db.SaveChanges();
return RedirectToAction("where u want it to redirect");
}
}
模型
public class RegisterTable
{
public int UserID
{ get; set; }
public string FirstName
{ get; set; }
public string LastName
{ get; set; }
public string Password
{ get; set; }
public string City
{ get; set; }
}
从视图中调用它
<table class="table">
<tr>
<th>
FirstName
</th>
<th>
LastName
</th>
<th>
City
</th>
<th></th>
</tr>
@foreach (var item in Model)
{
<tr>
<td> @item.FirstName </td>
<td> @item.LastName </td>
<td> @item.City</td>
<td>
<a href="@Url.Action("Edit", "Registeration", new { id = item.UserID })">Edit</a> |
<a href="@Url.Action("Details", "Registeration", new { id = item.UserID })">Details</a> |
<a href="@Url.Action("Delete", "Registeration", new { id = item.UserID })">Delete</a>
</td>
</tr>
}
</table>
我希望这对你来说很容易理解
var stud = (from s1 in entities.Students
where s1.ID== student.ID
select s1).SingleOrDefault();
//Delete it from memory
entities.DeleteObject(stud);
//Save to database
entities.SaveChanges();