Dropdown

See the DropdownDemo.cs.

using Gridrand.RimGui.Manual;
using System;
using System.Collections.Generic;

namespace Gridrand.RimGui.Extensions.Manual
{
    /// <summary>
    /// Demos such as 
    /// <see cref="GuiUtil.Dropdown(Gui, IReadOnlyList{string}, ISelectableItems{int}, bool, int)"/> and
    /// <see cref="GuiUtil.InputDropdown(Gui, IReadOnlyList{string}, ISelectableItems{int}, bool, int)"/>
    /// </summary>
    class DropdownDemo : ManualBase, IManual
    {
        SampleType type;
        SampleType inputType;
        SampleTypeFlags typeFlags;

        int selectedIndex;
        int inputSelectedIndex0;
        int inputSelectedIndex1;

        readonly DropdownItems dropdownItems = new();
        readonly DropdownItems inputDropdownItems = new();

        readonly string[] labels0 = new string[3]
        {
            "AAA",
            "BBB",
            "CCC",
        };

        readonly string[] lables1 = new string[9]
        {
            "012",
            "123",
            "234",
            "345",
            "456",
            "567",
            "678",
            "789",
            "890",
        };

        public DropdownDemo(ManualBaseResource p) : base(p)
        {
            dropdownItems.Select(0);
            inputDropdownItems.Select(0);
        }

        public void Draw()
        {
            Gui.Heading("Dropdown");
            Gui.Dropdown(labels0, ref selectedIndex);

            Gui.SmallSpacing();

            Gui.Text("Multiple select (Ctrl + Click)");
            Gui.Dropdown(labels0, dropdownItems, true);

            Gui.Heading("Dropdown(Enum)");
            // Pass the selected enum as the argument.
            Gui.Dropdown(ref type);


            Gui.Text("Multiple select (Ctrl + Click)");
            Gui.Dropdown(ref typeFlags);


            Gui.Heading("InputDropdown");
            Gui.InputDropdown(labels0, ref inputSelectedIndex0);

            // The items will be scrolled because their total height is greater than MaxHeights.
            using (ExStyle.Dropdown.MaxHeights.Begin(100))
                Gui.InputDropdown(lables1, ref inputSelectedIndex1);

            Gui.SmallSpacing();

            Gui.Text("Multiple select (Ctrl + Click)");
            Gui.InputDropdown(labels0, inputDropdownItems, true);

            Gui.Heading("InputDropdown(Enum)");
            Gui.InputDropdown(ref inputType);

        }

        enum SampleType
        {
            Element0,
            Element1,
            Element2
        }

        // If FlagsAttribute is attached, multiple selection is possible.
        [Flags]
        enum SampleTypeFlags
        {
            None = 0,
            Element1 = 1 << 0,
            Element2 = 1 << 1,
            Element3 = 1 << 2,
            Element4 = 1 << 3,
        }

        class DropdownItems : ISelectableItems<int>
        {
            readonly HashSet<int> values = new();

            public IEnumerable<int> Items => values;

            public void Deselect(int item) => values.Remove(item);
            public void DeselectAll() => values.Clear();
            public bool IsSelected(int item) => values.Contains(item);
            public void Select(int item) => values.Add(item);
        }
    }
}