Common-VS2019/SacsStandardMob/Mobile/Forms/Controls/SaxPicker.cs

using Sarand.Net.Standard.Base.Core;
using Sarand.Net.Standard.Base.Bus;
using System;
using System.Collections.Generic;
using System.Text;
using Xamarin.Forms;
using Sarand.Net.Standard.Base.Utils;

namespace Sarand.Net.Standard.Mobile.Forms.Controls
{
	//=======================================================================
	public class SaxPicker : Picker
	{
		//-------------------------------------------------------------------
		// Definitions.
		public class SlmPickerItem
		{
			public SysId Id { get; set; } = new SysId();
			public String Code { get; set; } = "";
			public String Caption { get; set; } = "";
			public Object Object { get; set; }
			public override string ToString ()
			{
				return Caption;
			}
		}

		//-------------------------------------------------------------------
		// Data members.
		private readonly List<SlmPickerItem> pickerItems = new List<SlmPickerItem>();

		//-------------------------------------------------------------------
		// Construction.
		public SaxPicker ()
		{
			DefaultFontSize = FontSize;
		}

		//-------------------------------------------------------------------
		// Properties.
		public double DefaultFontSize { get; }
		public bool BeingPopulated { get; protected set; } = false;

		//-------------------------------------------------------------------
		//                    P o p u l a t e   I t e m s
		//-------------------------------------------------------------------
		/// <summary>
		/// Does the list contain an item with the same Id.
		/// <para>NB Invalid Id values are matched.</para>
		/// </summary>
		public bool ContainsItemId (SysId id)
		{
			return pickerItems.Exists(item => SysId.ToInt(item.Id) == SysId.ToInt(id));
		}
		/// <summary>
		/// Does the list contain an item with the same code.
		/// <para>NB Codes are case-insensitive.</para>
		/// </summary>
		public bool ContainsItemCode (String code)
		{
			return pickerItems.Exists(item => item.Code.EqualsCI(code));
		}
		//-------------------------------------------------------------------
		/// <summary>Remove all items from the picker.</summary>
		public void ClearItems ()
		{
			Items.Clear();
			ItemsSource = null;
			pickerItems.Clear();
		}
		/// <summary>Replace existing picker item list.</summary>
		public void SetItems (List<SlmPickerItem> pickerItems)
		{
			ClearItems();
			this.pickerItems.AddRange(pickerItems);
			RefreshPickerItems();
		}
		//-------------------------------------------------------------------
		/// <summary>
		/// Add an item identified by a SysId value.
		/// <para>NB Fails if an item already exists with the same id.</para>
		/// </summary>
		public bool AddItem (SysId id, String caption)
		{
			if (ContainsItemId(id)) return false;
			pickerItems.Add(new SlmPickerItem() { Id = id, Caption = caption });
			RefreshPickerItems();
			return ContainsItemId(id);
		}
		/// <summary>
		/// Add an item identified by a code value.
		/// <para>NB Fails if an item already exists with the same case-insensitive code.</para>
		/// </summary>
		public bool AddItem (String code, String caption)
		{
			if (ContainsItemCode(code)) return false;
			pickerItems.Add(new SlmPickerItem() { Code = code, Caption = caption });
			RefreshPickerItems();
			return ContainsItemCode(code);
		}
		//-------------------------------------------------------------------
		private void RefreshPickerItems ()
		{
			//SetBinding(Picker.ItemsSourceProperty, BindableProperty.Create());
			//ItemDisplayBinding = new Binding("Caption");
			// Picker items doesn't automatically keep up to date with teh ItemsSource list.
			// So clear it and reset to force the refresh.
			ItemsSource = null;
			ItemsSource = pickerItems;
		}

		//-------------------------------------------------------------------
		//                    I t e m   S e l e c t i o n
		//-------------------------------------------------------------------
		public SlmPickerItem SelectedPickerItem
		{
			get
			{
				object selectedItem = SelectedItem;
				if (selectedItem == null || !(selectedItem is SlmPickerItem)) return null;
				return (selectedItem as SlmPickerItem);
			}
			set
			{
				if (SelectedPickerItem == value) return;
				if (ItemsSource == null || !ItemsSource.Contains(value)) return;
				base.SelectedItem = value;
			}
		}
		public SysId SelectedItemId
		{
			get
			{
				SlmPickerItem selectedPickerItem = SelectedPickerItem;
				return selectedPickerItem != null ? selectedPickerItem.Id : new SysId();
			}
			set
			{
				SelectedPickerItem = pickerItems.Find(item => item.Id.Equals(value));
			}
		}
		public String SelectedItemCode
		{
			get
			{
				SlmPickerItem selectedPickerItem = SelectedPickerItem;
				return selectedPickerItem != null ? selectedPickerItem.Code : "";
			}
			set
			{
				SelectedPickerItem = pickerItems.Find(item => item.Code.EqualsCI(value));
			}
		}

		//-------------------------------------------------------------------
		//                    C o n t r o l   E v e n t s
		//-------------------------------------------------------------------
		// Picker population completed.
		public class PopulatedEventArgs : EventArgs { }
		public delegate void PopulatedEventHandler (object sender, PopulatedEventArgs e);
		/// <summary>Picker population completed event handler.</summary>
		public event PopulatedEventHandler Populated;
		protected void InvokePopulatedEvent ()
		{
			if (Populated != null) Populated.Invoke(this, new PopulatedEventArgs() { });
		}

		//-------------------------------------------------------------------
	}
	//=======================================================================
}