I'm using C# on Framework 3.5. I'm looking to quickly sort a Generic List<T>. For the sake of this example, let's say I have a List of a Person type with a property of lastname. How would I sort this List using a lambda expression?
List<Person> people = PopulateList();
people.OrderBy(???? => ?????)
You can also use
model.People = model.People.OrderBy(x => x.Name).ToList();
This is a generic sorter. Called with the switch below.
dvm.PagePermissions is a property on my ViewModel of type List T in this case T is a EF6 model class called page_permission.
dvm.UserNameSortDir is a string property on the viewmodel that holds the next sort direction. The one that is actaully used in the view.
switch (sortColumn)
{
case "user_name":
dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.user_name, ref sortDir);
dvm.UserNameSortDir = sortDir;
break;
case "role_name":
dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.role_name, ref sortDir);
dvm.RoleNameSortDir = sortDir;
break;
case "page_name":
dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.page_name, ref sortDir);
dvm.PageNameSortDir = sortDir;
break;
}
public List<T> Sort<T,TKey>(List<T> list, Func<T, TKey> sorter, ref string direction)
{
if (direction == "asc")
{
list = list.OrderBy(sorter).ToList();
direction = "desc";
}
else
{
list = list.OrderByDescending(sorter).ToList();
direction = "asc";
}
return list;
}
people.OrderBy(person => person.lastname).ToList();
You can also use
model.People = model.People.OrderBy(x => x.Name).ToList();
you can use linq :) using :
System.linq;
var newList = people.OrderBy(x=>x.Name).ToList();
Do you need the list to be sorted in place, or just an ordered sequence of the contents of the list? The latter is easier:
var peopleInOrder = people.OrderBy(person => person.LastName);
To sort in place, you'd need an IComparer<Person> or a Comparison<Person>. For that, you may wish to consider ProjectionComparer in MiscUtil.
(I know I keep bringing MiscUtil up - it just keeps being relevant...)
people.OrderBy(person => person.lastname).ToList();
for me this useful dummy guide - Sorting in Generic List - worked. it helps you to understand 4 ways(overloads) to do this job with very complete and clear explanations and simple examples
You can use this code snippet:
var New1 = EmpList.OrderBy(z => z.Age).ToList();
where New1 is a List<Employee>.
EmpList is variable of a List<Employee>.
z is a variable of Employee type.
you can use linq :) using :
System.linq;
var newList = people.OrderBy(x=>x.Name).ToList();
people.OrderBy(person => person.lastname).ToList();
private void SortGridGenerico< T >(
ref List< T > lista
, SortDirection sort
, string propriedadeAOrdenar)
{
if (!string.IsNullOrEmpty(propriedadeAOrdenar)
&& lista != null
&& lista.Count > 0)
{
Type t = lista[0].GetType();
if (sort == SortDirection.Ascending)
{
lista = lista.OrderBy(
a => t.InvokeMember(
propriedadeAOrdenar
, System.Reflection.BindingFlags.GetProperty
, null
, a
, null
)
).ToList();
}
else
{
lista = lista.OrderByDescending(
a => t.InvokeMember(
propriedadeAOrdenar
, System.Reflection.BindingFlags.GetProperty
, null
, a
, null
)
).ToList();
}
}
}
Do you need the list to be sorted in place, or just an ordered sequence of the contents of the list? The latter is easier:
var peopleInOrder = people.OrderBy(person => person.LastName);
To sort in place, you'd need an IComparer<Person> or a Comparison<Person>. For that, you may wish to consider ProjectionComparer in MiscUtil.
(I know I keep bringing MiscUtil up - it just keeps being relevant...)
private void SortGridGenerico< T >(
ref List< T > lista
, SortDirection sort
, string propriedadeAOrdenar)
{
if (!string.IsNullOrEmpty(propriedadeAOrdenar)
&& lista != null
&& lista.Count > 0)
{
Type t = lista[0].GetType();
if (sort == SortDirection.Ascending)
{
lista = lista.OrderBy(
a => t.InvokeMember(
propriedadeAOrdenar
, System.Reflection.BindingFlags.GetProperty
, null
, a
, null
)
).ToList();
}
else
{
lista = lista.OrderByDescending(
a => t.InvokeMember(
propriedadeAOrdenar
, System.Reflection.BindingFlags.GetProperty
, null
, a
, null
)
).ToList();
}
}
}
Do you need the list to be sorted in place, or just an ordered sequence of the contents of the list? The latter is easier:
var peopleInOrder = people.OrderBy(person => person.LastName);
To sort in place, you'd need an IComparer<Person> or a Comparison<Person>. For that, you may wish to consider ProjectionComparer in MiscUtil.
(I know I keep bringing MiscUtil up - it just keeps being relevant...)
You can use this code snippet:
var New1 = EmpList.OrderBy(z => z.Age).ToList();
where New1 is a List<Employee>.
EmpList is variable of a List<Employee>.
z is a variable of Employee type.
This is a generic sorter. Called with the switch below.
dvm.PagePermissions is a property on my ViewModel of type List T in this case T is a EF6 model class called page_permission.
dvm.UserNameSortDir is a string property on the viewmodel that holds the next sort direction. The one that is actaully used in the view.
switch (sortColumn)
{
case "user_name":
dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.user_name, ref sortDir);
dvm.UserNameSortDir = sortDir;
break;
case "role_name":
dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.role_name, ref sortDir);
dvm.RoleNameSortDir = sortDir;
break;
case "page_name":
dvm.PagePermissions = Sort(dvm.PagePermissions, p => p.page_name, ref sortDir);
dvm.PageNameSortDir = sortDir;
break;
}
public List<T> Sort<T,TKey>(List<T> list, Func<T, TKey> sorter, ref string direction)
{
if (direction == "asc")
{
list = list.OrderBy(sorter).ToList();
direction = "desc";
}
else
{
list = list.OrderByDescending(sorter).ToList();
direction = "asc";
}
return list;
}
Do you need the list to be sorted in place, or just an ordered sequence of the contents of the list? The latter is easier:
var peopleInOrder = people.OrderBy(person => person.LastName);
To sort in place, you'd need an IComparer<Person> or a Comparison<Person>. For that, you may wish to consider ProjectionComparer in MiscUtil.
(I know I keep bringing MiscUtil up - it just keeps being relevant...)
people.OrderBy(person => person.lastname).ToList();
for me this useful dummy guide - Sorting in Generic List - worked. it helps you to understand 4 ways(overloads) to do this job with very complete and clear explanations and simple examples
Source: Stackoverflow.com