ToList().ForEach in Linq
C#LinqEntity FrameworkC# Problem Overview
I am new to Linq.
I want to set two values in foreach
statement like this
My actual code is this
foreach (Employee emp in employees)
{
foreach(Department dept in emp.Departments)
{
dept.SomeProperty = null;
}
collection.AddRange(emp.Departments);
}
Little refactoring turns the above into this
foreach (Employee emp in employees)
{
emp.Departments.ToList().ForEach(u => u.SomeProperty = null))
collection.AddRange(emp.Departments);
}
But I want something like this
employees.ToList().Foreach(collection.AddRange(emp.Departments),
emp.Departments.ToList().ForEach(u => u.SomeProperty = null))
C# Solutions
Solution 1 - C#
You shouldn't use ForEach
in that way. Read Lippert's “foreach” vs “ForEach”
If you want to be cruel with yourself (and the world), at least don't create useless List
employees.All(p => {
collection.AddRange(p.Departments);
p.Departments.All(u => { u.SomeProperty = null; return true; } );
return true;
});
Note that the result of the All
expression is a bool
value that we are discarding (we are using it only because it "cycles" all the elements)
I'll repeat. You shouldn't use ForEach
to change objects. LINQ should be used in a "functional" way (you can create new objects but you can't change old objects nor you can create side-effects). And what you are writing is creating so many useless List
only to gain two lines of code...
Solution 2 - C#
As xanatos said, this is a misuse of ForEach.
If you are going to use linq to handle this, I would do it like this:
var departments = employees.SelectMany(x => x.Departments);
foreach (var item in departments)
{
item.SomeProperty = null;
}
collection.AddRange(departments);
However, the Loop approach is more readable and therefore more maintainable.
Solution 3 - C#
employees.ToList().ForEach(
emp=>
{
collection.AddRange(emp.Departments);
emp.Departments.ToList().ForEach(u=>u.SomeProperty = null);
});
Solution 4 - C#
Try this:
foreach (var dept in employees.SelectMany(e => e.Departments))
{
dept.SomeProperty = null;
collection.Add(dept);
}
Solution 5 - C#
employees.ToList().Foreach(u=> { u.SomeProperty = null; u.OtherProperty = null; });
Notice that I used semicolons after each set statement
that is -->
u.SomeProperty = null;
u.OtherProperty = null;
I hope this will definitely solve your problem.
Solution 6 - C#
You can use Array.ForEach()
Array.ForEach(employees, employee => {
Array.ForEach(employee.Departments, department => department.SomeProperty = null);
Collection.AddRange(employee.Departments);
});
Solution 7 - C#
you want this?
employees.ForEach(emp =>
{
collection.AddRange(emp.Departments.Where(dept => { dept.SomeProperty = null; return true; }));
});
Solution 8 - C#
Try with this combination of Lambda expressions:
employees.ToList().ForEach(emp =>
{
collection.AddRange(emp.Departments);
emp.Departments.ToList().ForEach(dept => dept.SomeProperty = null);
});