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using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
namespace Xamarin.Forms.Controls
{
[Preserve (AllMembers = true)]
public class GroupedListContactsGallery
: ContentPage
{
internal class Contact
{
public string FirstName
{
get;
set;
}
public string LastName
{
get;
set;
}
public string FullName
{
get { return FirstName + " " + LastName; }
}
public string Title
{
get;
set;
}
}
readonly ListView _list = new ListView {
ItemTemplate = new DataTemplate (() => {
Label name = new Label();
name.SetBinding (Label.TextProperty, "FullName");
#pragma warning disable 618
Label title = new Label { Font = Font.SystemFontOfSize (NamedSize.Micro) };
#pragma warning restore 618
title.SetBinding (Label.TextProperty, "Title");
return new ViewCell { View = new StackLayout {
Children = {
name,
title
}
} };
}),
GroupDisplayBinding = new Binding ("Key"),
GroupShortNameBinding = new Binding ("Key"),
IsGroupingEnabled = true
};
readonly List<Contact> _contacts = new List<Contact> {
new Contact { FirstName = "Jason", LastName = "Smith", Title = "Software Engineer" },
new Contact { FirstName = "Eric", LastName = "Maupin", Title = "Software Engineer" },
new Contact { FirstName = "Seth", LastName = "Rosetter", Title = "Software Engineer" },
new Contact { FirstName = "Stephane", LastName = "Delcroix", Title = "Software Engineer" }
};
readonly Random _rand = new Random (42);
[Preserve (AllMembers = true)]
internal class Group
: ObservableCollection<Contact>
{
public Group (string key)
{
Key = key;
}
public string Key
{
get;
private set;
}
}
bool _sortedByFirst = true;
ObservableCollection<Group> _sortedContacts;
public GroupedListContactsGallery()
{
var addRandom = new Button { Text = "Random" };
addRandom.Clicked += (sender, args) => {
Contact contact = GetRandomContact();
_contacts.Add (contact);
AddContact (_sortedContacts, contact);
};
var addRandomToExisting = new Button { Text = "Random Group" };
addRandomToExisting.Clicked += (sender, args) => {
Contact contact;
do {
contact = GetRandomContact();
} while (!_sortedContacts.Any (g => GetSortChar (g.First()) == GetSortChar (contact)));
_contacts.Add (contact);
AddContact (_sortedContacts, contact);
};
var groupByFirst = new Button { Text = "First" };
groupByFirst.Clicked += (sender, args) => {
_sortedByFirst = true;
SetupContacts();
_list.ItemsSource = _sortedContacts;
};
var groupByLast = new Button { Text = "Last" };
groupByLast.Clicked += (sender, args) => {
_sortedByFirst = false;
SetupContacts();
_list.ItemsSource = _sortedContacts;
};
Content = new StackLayout {
Orientation = StackOrientation.Vertical,
Children = {
new StackLayout {
Orientation = StackOrientation.Vertical,
Children = {
new StackLayout {
Orientation = StackOrientation.Horizontal,
Children = {
new Label { Text = "Sort: " },
groupByFirst,
groupByLast
}
},
new StackLayout {
Orientation = StackOrientation.Horizontal,
Children = {
addRandom,
addRandomToExisting,
}
}
},
},
_list
}
};
SetupContacts();
_list.ItemsSource = _sortedContacts;
}
const string Chars = "abcdefghijklmnopqrstuvwxyz";
void SetupContacts()
{
var coll = new ObservableCollection<Group>();
foreach (var contact in _contacts)
AddContact (coll, contact);
_sortedContacts = coll;
}
void AddContact (ObservableCollection<Group> contactGroups, Contact contact)
{
char sortChar = GetSortChar (contact);
var collection = contactGroups.FirstOrDefault (col => {
var c = col.First();
return (GetSortChar (c) == sortChar);
});
if (collection == null) {
var ocontacts = new Group (GetSortChar (contact).ToString()) { contact };
InsertBasedOnSort (contactGroups, ocontacts, c => GetSortChar (c.First()));
} else
InsertBasedOnSort (collection, contact, c => GetSortString (c)[0]);
}
int IndexOf<T> (IEnumerable<T> elements, T element)
{
int i = 0;
foreach (T e in elements) {
if (Equals (e, element))
return i;
i++;
}
return -1;
}
void InsertBasedOnSort<T,TSort> (IList<T> items, T item, Func<T, TSort> sortBy)
{
List<T> newItems = new List<T> (items);
newItems.Add (item);
int index = IndexOf (newItems.OrderBy (sortBy), item);
items.Insert (index, item);
}
char GetSortChar (Contact contact)
{
return GetSortString (contact)[0];
}
string GetSortString (Contact contact)
{
return (_sortedByFirst) ? contact.FirstName : contact.LastName;
}
Contact GetRandomContact()
{
Contact contact = new Contact();
int firstLen = _rand.Next (3, 7);
var builder = new StringBuilder (firstLen);
for (int i = 0; i < firstLen; i++) {
char c = Chars[_rand.Next (0, Chars.Length)];
builder.Append ((i != 0) ? c : char.ToUpper (c));
}
contact.FirstName = builder.ToString();
int lastLen = _rand.Next (3, 7);
builder.Clear();
for (int i = 0; i < lastLen; i++) {
char c = Chars[_rand.Next (0, Chars.Length)];
builder.Append ((i != 0) ? c : char.ToUpper (c));
}
contact.LastName = builder.ToString();
contact.Title = "Software Engineer";
return contact;
}
}
}
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