I have read about the IEqualityComparer interface. Here is my code (which says more then a thousand words)
static void Main(string[] args)
{
var Send = new ObservableCollection<ProdRow>() {
new ProdRow() { Code = "8718607000065", Quantity = 1 },
new ProdRow() { Code = "8718607000911", Quantity = 10 }
};
var WouldSend = new ObservableCollection<ProdRow>() {
new ProdRow() { Code = "8718607000065", Quantity = 1 },
new ProdRow() { Code = "8718607000072", Quantity = 1 },
new ProdRow() { Code = "8718607000256", Quantity = 1 },
new ProdRow() { Code = "8718607000485", Quantity = 1 },
new ProdRow() { Code = "8718607000737", Quantity = 1 },
new ProdRow() { Code = "8718607000911", Quantity = 20 }
};
//var sendToMuch = Send.Except(WouldSend).ToList();
//var sendToLittle = WouldSend.Except(Send).ToList();
//if (sendToMuch.Any() || sendToLittle.Any())
// var notGood = true;
//else
// var okay = true;
var sendToMuch = Send.ToList();
var sendToLittle = WouldSend.ToList();
foreach (var s in Send) {
var w = WouldSend.FirstOrDefault(d => d.Code.Equals(s.Code));
if (w != null) {
if (w.Quantity == s.Quantity) {
sendToMuch.Remove(s);
sendToLittle.Remove(w);
continue;
}
if (w.Quantity > s.Quantity) {
sendToLittle.Single(l => l.Code == w.Code).Quantity = (w.Quantity - s.Quantity);
sendToMuch.Remove(s);
} else {
sendToMuch.Single(l => l.Code == w.Code).Quantity = (s.Quantity - w.Quantity);
sendToLittle.Remove(s);
}
} else {
sendToMuch.Add(s);
}
}
}
The commented lines where what I would hoped that would work... the stuff below with what I ended up with.
As reference, here is my ProdRow class:
class ProdRow : INotifyPropertyChanged, IEqualityComparer<ProdRow>
{
private string _code;
private int _quantity;
public string Code {
get { return _code; }
set {
_code = value;
OnPropertyChanged("Code");
}
}
public int Quantity {
get { return _quantity; }
set {
_quantity = value;
OnPropertyChanged("Quantity");
}
}
private void OnPropertyChanged(string v) {
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(v));
}
public new bool Equals(object x, object y) {
if (((ProdRow)x).Code.Equals(((ProdRow)y).Code) && ((ProdRow)x).Quantity == ((ProdRow)y).Quantity)
return true;
else
return false;
}
public int GetHashCode(object obj) {
return obj.GetHashCode();
}
public bool Equals(ProdRow x, ProdRow y) {
if (x.Code.Equals(y.Code) && x.Quantity == y.Quantity)
return true;
else
return false;
}
public int GetHashCode(ProdRow obj) {
throw new NotImplementedException();
}
public event PropertyChangedEventHandler PropertyChanged;
}
I did not expected the commented part to work, because it cannot know to decrease the int of quantity etc. but I would like to know if there is a more efficient way to do this then the solution I used (below the commented lines). Perhaps flatten the collection like a string[]?
P.S. Sorry for the "PascalCase" of Send and WouldSend
IEqualityComparer<T> is not the right interface to implement for a class whose instances you wish to compare. IEqualityComparer<T> implementations are for creating objects that do comparisons from the outside of the objects being compared, which becomes important when you need to re-define what it means for two objects to be equal without access to the code of these objects, or when you need to use different semantic for equality depending on the context.
The right interface for strongly typed equality comparison is IEquatable<T>. However, in your case all you need is overriding Object's Equals(object) and GetHashCode():
public new bool Equals(object obj) {
if (obj == this) return true;
var other = obj as ProdRow;
if (other == null) return false;
return Code.Equals(other.Code) && Quantity == other.Quantity;
}
public int GetHashCode() {
return 31*Code.GetHashCode() + Quantity;
}
As far as computing quantities goes, you can do it with negative numbers and GroupBy:
var quantityByCode = WouldSend.Select(p => new {p.Code, p.Quantity})
.Concat(Send.Select(p => new {p.Code, Quantity = -p.Quantity}))
.GroupBy(p => p.Code)
.ToDictionary(g => g.Key, g => g.Sum(p => p.Quantity));
var tooLittle = quantityByCode
.Where(p => p.Value > 0)
.Select(p => new ProdRow {Code = p.Key, Quantity = p.Value})
.ToList();
var tooMuch = quantityByCode
.Where(p => p.Value < 0)
.Select(p => new ProdRow {Code = p.Key, Quantity = -p.Value})
.ToList();
Related
My List contains multiple subjects, but some of them are the same. How to display all of them but without repetitions?
public class Subject
{
public string SubjectName { get; set; }
public Subject(string subjectName)
{
this.SubjectName = subjectName;
}
}
List<Subject> listOfSubjects = new List<Subject>();
string subject = "";
Console.WriteLine("Enter the name of the subject");
subject = Console.ReadLine();
listofSubjects.Add(new Subject(subject));
string pastSubject = "";
foreach (Subject sub in listOfSubjects)
{
if (sub.SubjectName != pastSubject)
{
Console.WriteLine(sub.SubjectName);
}
pastSubject = sub.SubjectName;
}
One solution can be to build a IEqualityComparer<Subject> for the Subject class. Below is code for it.
public class SubjectComparer : IEqualityComparer<Subject>
{
public bool Equals(Subject x, Subject y)
{
if (x == null && y == null)
{
return true;
}
else if (x == null || y == null)
{
return false;
}
else
{
return x.SubjectName == y.SubjectName;
}
}
public int GetHashCode(Subject obj)
{
return obj.SubjectName.GetHashCode();
}
}
Then just call the System.Linq Distinct function on it supplying the IEqualityComparer instance.
List<Subject> distinctSubjects = listOfSubjects.Distinct(new SubjectComparer()).ToList();
The resultant distinctSubjects list is Distinct.
If you use Linq then you can use GroupBy to get the distinct Subjects by name.
var distinctList = listOfSubjects
.GroupBy(s => s.SubjectName) // group by names
.Select(g => g.First()); // take the first group
foreach (var subject in distinctList)
{
Console.WriteLine(subject.SubjectName);
}
This method returns IEnumerable<Subject>, ie a collection of the actual Subject class.
I created a fiddle.
You can get distinct subject names with
var distinctSubjectNames = listOfSubjects
.Select(s => s.SubjectName)
.Distinct();
foreach (string subjectName in distinctSubjectNames) {
Console.WriteLine(subjectName);
}
I have two lists AuthorList & AuthorList2. At the moment I am using union with simple IEqualityComparer class.
I expect to have a result list without any duplicates from AuthorList & AuthorList2 and if there are any duplicates in those lists, they need to be removed from the lists and the Author class Assigned property needs to be set true for the duplicate item.
Existing information from both AuthorLists:
ProductID & Assigned
1, false
2, false
3, false
1, false
Result list:
ProductID & Assigned
1, true
2, false
3, false
The logic needs to filter out duplicates and if both of those lists have the same element, change false -> true.
namespace HelloWorld
{
class Hello
{
static void Main()
{
List<Author> AuthorList = new List<Author>
{
new Author(1, false),
new Author(2, false),
new Author(3, false)
};
List<Author> AuthorList2 = new List<Author>
{
new Author(1, false)
};
var compareById = new AuthorComparer(false);
var result = AuthorList.Union(AuthorList2, compareById);
foreach (var item in result)
{
Console.WriteLine("Result: {0},{1}", item.ProductId, item.Assigned);
}
Console.ReadKey();
}
public class AuthorComparer : IEqualityComparer<Author>
{
private bool m_withValue;
public AuthorComparer(bool withValue)
{
m_withValue = withValue;
}
public bool Equals(Author x, Author y)
{
return (x.ProductId == y.ProductId);
}
public int GetHashCode(Author x)
{
return x.ProductId.GetHashCode();
}
}
public class Author
{
private int productId;
private bool assigned;
public Author(int productId, bool assigned)
{
this.productId = productId;
this.assigned = assigned;
}
public int ProductId
{
get { return productId; }
set { productId = value; }
}
public bool Assigned
{
get { return assigned; }
set { assigned = value; }
}
}
}
}
The code you're looking for is this:
AuthorList.ForEach(a => a.Assigned = AuthorList2.Exists(b => b.ProductId == a.ProductId));
You don't need the IEqualityComparer at all.
Full, working code:
namespace HelloWorld
{
class Hello
{
static void Main()
{
List<Author> AuthorList = new List<Author>
{
new Author(1, false),
new Author(2, false),
new Author(3, false)
};
List<Author> AuthorList2 = new List<Author>
{
new Author(1, false)
};
AuthorList.ForEach(a => a.Assigned = AuthorList2.Exists(b => b.ProductId == a.ProductId));
foreach (var item in AuthorList)
{
Console.WriteLine("Result: {0},{1}", item.ProductId, item.Assigned);
}
Console.ReadKey();
}
public class Author
{
public Author(int productId, bool assigned)
{
this.ProductId = productId;
this.Assigned = assigned;
}
public int ProductId { get; set; }
public bool Assigned { get; set; }
}
}
}
With your comparer, you can use:
foreach (var author in AuthorList.Intersect(AuthorList2, compareById))
{
author.Assigned = true;
}
You can do it without that easily enough as well if you don't need the comparer for anything else:
var author2Ids = new HashSet<int>(AuthorList2.Select(a => a.ProductId));
foreach (var author in AuthorList.Where(a => author2Ids.Contains(a.ProductId)))
{
author.Assigned = true;
}
... but if you need the comparer for anything else, or if it may get more complex, I'd stick to using that.
Try with something like this. Please look at ! carefully
//Separate out different entries from both the lists
var diffList = AuthorList.Where(x => !AuthorList2.Any(y => y.ProductId== x.ProductId && y.Assigned== x.Assigned)).ToList();
//Separate out common entries from both the list
var commonList = AuthorList.Where(x => AuthorList2.Any(y => y.ProductId== x.ProductId && y.Assigned== x.Assigned)).ToList();
//Change value of Assigned
commonList.ForEach(x => x.Assigned = !x.Assigned);
//Merge both the lists
diffList.AddRange(commonList);
POC: DotNetFiddler
This will produce a new List of elements without altering the source:
private static List<Author> FilterDuplicates(List<Author> x, List<Author> y)
{
return x.Select(author => new Author(author.ProductId, y.Exists(a => a.ProductId == author.ProductId))).ToList();
}
I am developing my first WPF browser application.
I load invoices in a dataGrid then I filter with textBox or comboBox.
Because it takes few seconds to load, I'am trying to put a loading animation according the following example:
here
It doesn't work the first time I navigate to the page. My dataGrid remains empty. When I debug I have this following error which happens on my query in Get() function.
'System.Data.Entity.Core.EntityCommandExecutionException' occurred in mscorlib.dll but was not handled in user code
But the this query used to work well before I made the changes for the animation. So maybe the problem doesn't come from the query.
Exception:Thrown: "Connection must be valid and open." (System.InvalidOperationException)
A System.InvalidOperationException was thrown: "Connection must be valid and open."
Time: 11/20/2015 12:36:31 PM
Thread:Worker Thread[13324]
public class ConsultInvoiceViewModel : ViewModelBase
{
public Context ctx = new Context();
private ICollectionView _dataGridCollection;
private string _filterString;
private ObservableCollection<Invoice> invoiceCollection;
public ConsultInvoiceViewModel()
{
if (!WPFHelper.IsInDesignMode)
{
var tsk = Task.Factory.StartNew(InitialStart);
tsk.ContinueWith(t => { MessageBox.Show(t.Exception.InnerException.Message); }, CancellationToken.None, TaskContinuationOptions.OnlyOnFaulted, TaskScheduler.FromCurrentSynchronizationContext());
}
}
private void InitialStart()
{
try
{
State = StateEnum.Busy;
DataGridCollection = CollectionViewSource.GetDefaultView(Get());
DataGridCollection.Filter = new Predicate<object>(Filter);
GetShop(); //load one comboBox
GetSupplier(); //load one comboBox
}
finally
{
State = StateEnum.Idle;
}
}
private ObservableCollection<Invoice> Get()
{
DateTime date2 = DateTime.Now.AddMonths(-2);
var query = ctx.Invoices
.GroupBy(x => new { x.suppInvNumber, x.shop1, x.date, x.foodSupplier })
.ToList()
.Select(i => new Invoice
{
suppInvNumber = i.Key.suppInvNumber,
shop1 = i.Key.shop1,
date = i.Key.date,
foodSupplier = i.Key.foodSupplier,
totalPrice = i.Sum(t => t.totalPrice),
})
.Where(d => d.date >= date2)
.OrderByDescending(d => d.date)
.AsQueryable();
invoiceCollection = new ObservableCollection<Invoice>(query);
return invoiceCollection;
}
public ICollectionView DataGridCollection
{
get
{
return _dataGridCollection;
}
set
{
_dataGridCollection = value;
OnPropertyChanged("DataGridCollection"); }
}
public string FilterString
{
get
{
return _filterString;
}
set
{
_filterString = value;
OnPropertyChanged("FilterString");
FilterCollection();
}
}
public static readonly PropertyChangedEventArgs StateArgs = ViewModelBase.CreateArgs<ConsultInvoiceViewModel>(c => c.State);
private StateEnum _State;
public StateEnum State
{
get
{
return _State;
}
set
{
var oldValue = State;
_State = value;
if (oldValue != value)
{
OnStateChanged(oldValue, value);
OnPropertyChanged(StateArgs);
}
}
}
protected virtual void OnStateChanged(StateEnum oldValue, StateEnum newValue)
{
}
private void FilterCollection()
{
if (_dataGridCollection != null)
{
_dataGridCollection.Refresh();
}
}
private bool Filter(object obj)
{
var data = obj as Invoice;
if (data != null)
{
if (!string.IsNullOrEmpty(_filterString))
{
return data.suppInvNumber.Contains(_filterString);
}
return true;
}
return false;
}
private void SearchFilter()
{
IOrderedEnumerable<Invoice> invs;
invs = ctx.Invoices
.Where(s => s.shop == Shop && s.supplier == Supplier && s.date >= From && s.date <= To)
.GroupBy(x => new {x.suppInvNumber, x.shop1, x.date, x.foodSupplier })
.ToList()
.Select(i => new Invoice
{
suppInvNumber = i.Key.suppInvNumber,
shop1 = i.Key.shop1,
date = i.Key.date,
foodSupplier = i.Key.foodSupplier,
totalPrice = i.Sum(t => t.totalPrice),
})
.OrderByDescending(d => d.date);
}
invoiceCollection.Clear();
if (invs != null)
foreach (var inv in invs)
{
invoiceCollection.Add(inv);
}
FilterCollection();
}
#region combobox
private void GetShop()
{
ctx.shops.ToList().ForEach(shop => ctx.shops.Local.Add(shop));
SShop = ctx.shops.Local;
}
private void GetSupplier()
{
ctx.foodSuppliers.ToList().ForEach(supplier => ctx.foodSuppliers.Local.Add(supplier));
FoodSupplier = ctx.foodSuppliers.Local;
}
private IList<foodSupplier> supplier;
public IList<foodSupplier> FoodSupplier
{
get
{
if (supplier == null)
GetSupplier();
return supplier;
}
set
{
supplier = value;
OnPropertyChanged("FoodSupplier");
}
}
private IList<shop> shop;
public IList<shop> SShop
{
get
{
return shop;
}
set
{
shop = value;
OnPropertyChanged("SShop");
}
}
private int _shop;
public int Shop
{
get
{
return _shop;
}
set
{
_shop = value;
OnPropertyChanged("Shop");
SearchFilter();
}
}
private int _supplier;
public int Supplier
{
get
{
return _supplier;
}
set
{
_supplier = value;
OnPropertyChanged("Supplier");
SearchFilter();
}
}
#endregion
#region "Command"
private ICommand searchCommand;
public ICommand SearchCommand
{
get
{
return searchCommand ?? (searchCommand = new RelayCommand(p => this.Search(), p => this.CanSearch()));
}
}
private bool CanSearch()
{
return true;
}
#endregion
}
The exception you are getting indicates an error connecting to the database. It's hard to diagnose this because of the way you keep a single Context reference for the life of the application. That connection could be failing at any point.
Try wrapping your data access in a new Context for each logical operation like this. Keeping one Context around for the life of an application is an Anti-pattern that can lead to all kinds of errors, especially when trying to do things in the background.
private ObservableCollection<Invoice> Get()
{
using (var ctx = new Context())
{
DateTime date2 = DateTime.Now.AddMonths(-2);
var query = ctx.Invoices
.GroupBy(x => new { x.suppInvNumber, x.shop1, x.date, x.foodSupplier })
.ToList()
.Select(i => new Invoice
{
suppInvNumber = i.Key.suppInvNumber,
shop1 = i.Key.shop1,
date = i.Key.date,
foodSupplier = i.Key.foodSupplier,
totalPrice = i.Sum(t => t.totalPrice),
})
.Where(d => d.date >= date2)
.OrderByDescending(d => d.date)
.AsQueryable();
invoiceCollection = new ObservableCollection<Invoice>(query);
}
return invoiceCollection;
}
I have the a few methods that have similar signature and was trying to convert them into one generic one without the use of interfaces.
public List<MultiSelectDropdown> ConvertListOfJobStatusToDropdownListClickable(List<JobStatus> js) {
var list = new List<MultiSelectDropdown>();
if (js != null && js.Count >= 1) {
list = js.Select(item => new MultiSelectDropdown { Name = item.StatusValue, Value = item.id.ToString() }).ToList();
}
return list;
}
public List<MultiSelectDropdown> ConvertListOfCUsersToDropdownListClickable(List<cUser> users) {
var list = new List<MultiSelectDropdown>();
if (users != null && users.Count >= 1) {
list = users.Select(item => new MultiSelectDropdown { Name = item.User_Name, Value = item.Id.ToString() }).ToList();
}
return list;
}
This is what I would like to do; pass in a list with two properties.
List<MultiSelectDropdown> ddlForClientUsers = ConvertToMultiSelectDropdownList(listOfClientsForUser, n => n.Client_Id, v => v.Client);
List<MultiSelectDropdown> ddlForJobStatus = ConvertToMultiSelectDropdownList(listOfJobStatus, n => n.Id, v => v.JobName);
This is the method I have tried but not sure how to get item.propName and item.propValue to work.
I get "Cannot resolve" propName and propValue in the method below
Is this possible?
public List<MultiSelectDropdown> ConvertToMultiSelectDropdownList<T, TPropertyName, TPropertyValue>(List<T> listOfT, Func<T, TPropertyName> propName, Func<T, TPropertyValue> propValue) {
var list = new List<MultiSelectDropdown>();
if (listOfT != null && listOfT.Count >= 1) {
list = listOfT.Select(item => new MultiSelectDropdown { Name = item.propName, Value = item.propValue }).ToList();
}
return list;
}
public class MultiSelectDropdown {
public string Name { get; set; }
public string Value { get; set; }
public bool IsChecked { get; set; }
}
Because the properties of your MultiSelectDropdown are strings, your functions should return those as well. And to invoke the functions, you have to write them like propName(item) instead of item.propName - that is the property syntax, and you indicated you didn't want to use interfaces.
public List<MultiSelectDropdown> ConvertToMultiSelectDropdownList<T>(List<T> listOfT, Func<T, string> propName, Func<T, string> propValue) {
var list = new List<MultiSelectDropdown>();
if (listOfT != null && listOfT.Count >= 1) {
list = listOfT.Select(item => new MultiSelectDropdown { Name = propName(item), Value = propValue(item) }).ToList();
}
return list;
}
You are really close, with just a slight mistake. The line (reformatted to prevent scrolling):
list = listOfT.Select(item => new MultiSelectDropdown
{
Name = item.propName,
Value = item.propValue
}).ToList();
needs to be:
list = listOfT.Select(item => new MultiSelectDropdown
{
Name = propName(item),
Value = propValue(item)
}).ToList();
I have two Lists
ListA<Emp> and ListB<Emp>
both are having 1000 records.
Emp is an object of Employee Class. Below is my Employee class
public class Employee
{
int ID = 0;
string Name = String.Empty;
string Dept = String.Empty;
string Address = String.Empty;
int Age = 0;
string Email = String.Empty;
}
I want to verify if both the Lists are equal. The Emp objects may be placed in different order. Also, there might be several Emp objects which are having exactly same info in both the list. I have to verify those also.
I tried to sort the lists and compared using SequenceEqual
Enumerable.SequenceEqual(ListA.OrderBy(s => s), ListB.OrderBy(s => s)
I am getting below error
At least one object must implement IComparable.
Exception Stack trace is as below
at System.Collections.Comparer.Compare(Object a, Object b)
at System.Collections.Generic.ObjectComparer`1.Compare(T x, T y)
at System.Linq.EnumerableSorter`2.CompareKeys(Int32 index1, Int32 index2)
at System.Linq.EnumerableSorter`1.QuickSort(Int32[] map, Int32 left, Int32 right)
at System.Linq.EnumerableSorter`1.Sort(TElement[] elements, Int32 count)
at System.Linq.OrderedEnumerable`1.<GetEnumerator>d__0.MoveNext()
at System.Linq.Enumerable.SequenceEqual[TSource](IEnumerable`1 first, IEnumerable`1 second, IEqualityComparer`1 comparer)
at System.Linq.Enumerable.SequenceEqual[TSource](IEnumerable`1 first, IEnumerable`1 second)
How can I implement this ? Also it will be better if you guys can provide me the fastest way of doing this because the number of objects in List may grow to 10 million.
Thanks for your help !
EDIT: Every employee must be in both list, order does not matter. But, if ListA contains same employee object 5 times (that means some duplicate entries), and ListB contains the employee object 4 times, then ListA and ListB are not equal.
You can use SequenceEqual with a custom IEqualityComparer<Employee>:
class EmployeeComparer : IEqualityComparer<Employee>
{
public bool Equals(Employee x, Employee y)
{
if (x == null || y == null) return false;
bool equals = x.ID==y.ID && x.Name == y.Name && x.Dept == y.Dept
&& x.Address == y.Address && x.Age == y.Age && x.Email == y.Email;
return equals;
}
public int GetHashCode(Employee obj)
{
if (obj == null) return int.MinValue;
int hash = 19;
hash = hash + obj.ID.GetHashCode();
hash = hash + obj.Name.GetHashCode();
hash = hash + obj.Dept.GetHashCode();
hash = hash + obj.Address.GetHashCode();
hash = hash + obj.Age.GetHashCode();
hash = hash + obj.Email.GetHashCode();
return hash;
}
}
Now it's so simple:
listA.SequenceEqual(ListB, new EmployeeComparer());
If the order is not important and you only want to know if all employees are in both lists you can use HashSet<Employee>.SetEquals to determine if both lists contain the same people:
var empComparer = new EmployeeComparer();
bool bothEqual = new HashSet<Employee>(ListA, empComparer)
.SetEquals(new HashSet<Employee>(ListB, empComparer));
Best complexity is O(N)
Following realization with using HashSet:
Class with implementation of GetHashCode and Equals:
public class Employee
{
public int ID = 0;
public string Name = String.Empty;
public string Dept = String.Empty;
public string Address = String.Empty;
public int Age = 0;
public string Email = String.Empty;
public override int GetHashCode()
{
return
ID.GetHashCode() ^
(Name ?? String.Empty).GetHashCode() ^
(Dept ?? String.Empty).GetHashCode() ^
(Address ?? String.Empty).GetHashCode() ^
Age.GetHashCode() ^
(Email ?? String.Empty).GetHashCode()
;
}
public override bool Equals(object obj)
{
Employee other = obj as Employee;
if (obj == null)
return false;
return ID == other.ID &&
Name == other.Name &&
Dept == other.Dept &&
Address == other.Address &&
Age == other.Age &&
Email == other.Email;
}
}
Function to compare lists:
public static bool CompareLists(List<Employee> list1, List<Employee> list2)
{
if (list1 == null || list2 == null)
return list1 == list2;
if (list1.Count != list2.Count)
return false;
Dictionary<Employee, int> hash = new Dictionary<Employee, int>();
foreach (Employee employee in list1)
{
if (hash.ContainsKey(employee))
{
hash[employee]++;
}
else
{
hash.Add(employee, 1);
}
}
foreach (Employee employee in list2)
{
if (!hash.ContainsKey(employee) || hash[employee] == 0)
{
return false;
}
hash[employee]--;
}
return true;
}
If the numbers in the list are going to grow enormous (10M), you are probably going to have to consider parallelization of the look-up to get an acceptable query time.
Consider using PLINQ.
Some more clarity on what you mean by 'equal' would be good. How complex is the equivalence check? Are you checking that the objects are the same or that the objects values are the same?
Another consideration would be this; if the number of elements are going to become large, could you consider moving this check down from .NET into your database - perhaps as a stored procedure? You may find it executes more efficiently there.
reduce the list to a scalar type: int, string, ....
L1.Select(x => x.K).ToArray()
use the except method
L1.Select(x => x.K).ToArray().Except(L1.Select(x => x.K).ToArray())
If the count of the resulting set is 0 then the List are equals
L1.Select(x => x.K).ToArray().Except(L1.Select(x => x.K).ToArray()).Count()
All together
public class Program {
public static void Main(String[] args) {
List<O> L1 = new List<O>{
new O {K = 1, V = "abcd"},
new O {K = 2, V = "efgh"}
};
List<O> L2 = new List<O>{
new O {K = 1, V = "abcd"}
};
List<O> L3 = new List<O>{
new O {K = 1, V = "abcd"},
new O {K = 3, V = "ijkl"}
};
List<O> L4 = new List<O>{
new O {K = 2, V = "efgh"},
new O {K = 1, V = "abcd"}
};
Console.WriteLine(L1.Select(x => x.K).ToArray().Except(L1.Select(x => x.K).ToArray()).Count());
Console.WriteLine(L1.Select(x => x.K).ToArray().Except(L2.Select(x => x.K).ToArray()).Count());
Console.WriteLine(L1.Select(x => x.K).ToArray().Except(L3.Select(x => x.K).ToArray()).Count());
Console.WriteLine(L1.Select(x => x.K).ToArray().Except(L4.Select(x => x.K).ToArray()).Count());
}
}
public class O {
public int K { get; set; }
public String V { get; set; }
}
Exactly what it says.
Implement IComparable on the class Employee
Also need to override Equals
Due to potentially a large number of calls to GetHashCode save it and only calculate on changes.
Tested
IComparable Interface
public MainWindow()
{
InitializeComponent();
List<Person> PLa = new List<Person>();
List<Person> PLb = new List<Person>();
PLa.Add(new Person { Age = 3, Name = "Jim"});
PLa.Add(new Person { Age = 2, Name = "Jimmmy" });
PLa.Add(new Person { Age = 1, Name = "Jim" });
PLb.Add(new Person { Age = 1, Name = "Jim" });
PLb.Add(new Person { Age = 3, Name = "Jim" });
PLb.Add(new Person { Age = 2, Name = "Jimmmy" });
System.Diagnostics.Debug.WriteLine(ListSameIgnoreOrder(PLa, PLb));
}
public bool ListSameIgnoreOrder(List<Person> PLa, List<Person> PLb)
{
if (PLa.Count != PLb.Count) return false;
//PLa.Sort();
//PLb.Sort();
return Enumerable.SequenceEqual(PLa.OrderBy(s => s), PLb.OrderBy(s => s));
//for (int i = 0; i < PLa.Count; i++)
//{
// System.Diagnostics.Debug.WriteLine(
// PLa[i].Age.ToString() + " " + PLb[i].Age.ToString() + " " +
// PLa[i].Name + " " + PLb[i].Name);
// if (!PLa[i].Equals(PLb[i])) return false;
//}
//return true;
}
public class Person : object, IComparable
{
private int age = 0;
private string name = string.Empty;
private int hash;
public int Age
{
get { return age; }
set
{
if (age == value) return;
age = value;
CalcHash();
}
}
public string Name
{
get { return name; }
set
{
if (name == value) return;
name = value;
CalcHash();
}
}
public override bool Equals(Object obj)
{
//Check for null and compare run-time types.
if (obj == null || !(obj is Person)) return false;
Person f = (Person)obj;
if (f.Age != this.Age) return false;
return (string.Compare(f.name, this.name) == 0);
}
private void CalcHash()
{
hash = Age.GetHashCode() ^
(Name ?? String.Empty).GetHashCode();
}
public override int GetHashCode()
{
return hash;
//return age ^ name.GetHashCode();
}
public int CompareTo(object obj)
{
if (obj == null) return 1;
Person otherPerson = obj as Person;
if (otherPerson != null)
{
if (otherPerson.Age > this.Age) return -1;
if (otherPerson.Age < this.Age) return 1;
// compare all properties like above
return string.Compare(otherPerson.name, this.name);
}
else
throw new ArgumentException("Object is not a Person");
}
public Person() { CalcHash(); }
}
This works.
public bool EqualList(Dictionary<int, string> a, Dictionary<int, string> b)
{
if (a.Count == b.Count)
{
bool rs = false;
foreach (var i in a)
{
if (b.ContainsKey(i.Key))
{
rs = true;
}
else
{
rs = false;
break;
}
}
return rs;
}
else
{
return false;
}
Usage:
if(EqualList(List<A>.ToDictionary(k => k.Key, k => k.Value), List<B>.ToDictionary(k => k.Key, k => k.Value)){
}else{
}