NewPage1.xaml.cs 29Jan

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Windows.Input;
using CommunityToolkit.Mvvm.ComponentModel;
using Microsoft.Maui.Platform;
namespace MM2.Views;
public partial class NewPage1 : ContentPage
{
    public partial class Item : ObservableObject
    {
        [ObservableProperty] public string acct;
        [ObservableProperty] public decimal amount;

        public int tag;

        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
    public partial class MyViewModel : ObservableObject
    {
        Item _SelectedItem;
        public Item SelectedItem
        {
            get { return _SelectedItem; }
            set
            {
                if (_SelectedItem == value) return;
                _SelectedItem = value;
                OnPropertyChanged();
            } // OnPropertyChanged needed/okay/bad?
        }
        private ObservableCollection<Item> _ItemsOC;
        public ObservableCollection<Item> ItemsOC
        {
            get { return _ItemsOC; }
            set
            {
                if (_ItemsOC == value) return;
                _ItemsOC = value;
                OnPropertyChanged();
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public ObservableCollection<Item> ItemsOC { get;  set; }
    Item OneItem { get; set; }
    Item OneMini { get; set; }
    Item ItemMaybe { get; set; }

    string Q;
    MyTable tbl;
    int MiniIndex = 0;
    ViewModels.MyViewModelx vmx;
    MyViewModel vm;

    public NewPage1()
    {
        InitializeComponent();
        vmx = new ViewModels.MyViewModelx();
        BindingContext = vmx;
        vmx.theDate = DateTime.Today;
        vmx.anInt = 1234;

        vm = new MyViewModel();
        BindingContext = vm;
        Setup();
   }
   void Setup()
    {
        int hjkl = vmx.anInt+5432; // for debug only
        Q = "SELECT AcctName, AcctBalance FROM Assets;";
        tbl = new(Q);
        int NumRows = tbl.numRows; //3
        int NumCols = tbl.numCols; //2

        ItemsOC = new();
        BindingContext = this;
        for (int i = 0; i < NumRows; i++)
        {
            OneItem = new();
            string[] aRow = tbl.GetRow(i);
            OneItem.acct = aRow[0];
            OneItem.amount = Convert.ToDecimal(aRow[1]);
            OneItem.tag = i;
            ItemsOC.Add(OneItem);
        }
        MiniIndex = -1;      // ** gray out
        SetButtonsVisible(); // ** buttons
    }
    private void MiniView_SelectionChanged(object s, EventArgs e)
    {
        if (MiniView.SelectedItem is null) return;
        OneMini = (Item)MiniView.SelectedItem;

        int tag = OneMini.tag;
        int index = ItemsOC.IndexOf(ItemsOC.Where
            (X => X.tag == tag).FirstOrDefault());
        if (index == -1)
        {
            return; // trap this line for debug
        }
        // index is valid
        MiniIndex = index;
        SetButtonsVisible(); // up/down/remove
    } // END MiniView_SelectionChanged(object s, EventArgs e)
    void click(object sender, EventArgs e)
    {
        int c = ItemsOC.Count;
        if (c < 1) return;
        // swap bottom to top
        ItemsOC.Move(c - 1, 0);
        // reverse the above
        ItemsOC.Move(0, c - 1);
    }
    void SetButtonsVisible()
    {
     //   Color LiteGrey = Color.FromRgb(64,64,64);
     //   Color std = Color.FromRgb(0,0,128);

        bool up = true;
        bool down = true;
        bool top = true;
        bool del = true;
        int max = ItemsOC.Count - 1;
        if (max <= 0 || MiniIndex < 0)
        {
            up = false;
            down = false;
            top = false;
            del = false;
        }
        if (MiniIndex == 0) up = top = false;
        if (MiniIndex == max) down = false;
        bUp.IsEnabled = up;
        bDwn.IsEnabled = down;
        bDel.IsEnabled = del;
        bTop.IsEnabled = top;
    }
    void clickDown(object s, EventArgs e)
    {
        ItemsOC.Move(MiniIndex, MiniIndex+1);
        MiniIndex++;
        MiniView.SelectedItem = ItemsOC[MiniIndex];
        SetButtonsVisible();
    }
    void clickToTop(object s, EventArgs e)
    {
        ItemsOC.Move(MiniIndex, 0);
        MiniIndex = 0;
        MiniView.SelectedItem = ItemsOC[MiniIndex];
        SetButtonsVisible();
    }
    void clickDelete(object s, EventArgs e)
    {
        ItemsOC.RemoveAt(MiniIndex);
        MiniIndex = -1;
        SetButtonsVisible();
    }
    void clickUp(object s, EventArgs e)
    {
        ItemsOC.Move(MiniIndex, MiniIndex-1);
        MiniIndex--;
        MiniView.SelectedItem = ItemsOC[MiniIndex];
        SetButtonsVisible();
    }

} // END partial class NewPage1