3rdpartylibs/fastreports.wpf/FastReport.Forms.WPF/Controls/SplitContainer.cs

using System.ComponentModel;
using System.Drawing;

namespace System.Windows.Forms
{
    public class SplitContainer : ContainerControl, ISupportInitialize
    {
        private Splitter Splitter { get; }

        public SplitterPanel Panel1 { get; }

        public SplitterPanel Panel2 { get; }

        public int Panel1MinSize { get; set; } // TODO

        public int Panel2MinSize { get; set; } // TODO

        private Orientation orientation;
        public Orientation Orientation
        {
            get => orientation;
            set
            {
                if (orientation != value)
                {
                    orientation = value;

                    SuspendLayout();
                    if (value == Orientation.Vertical)
                    {
                        if (FixedPanel == FixedPanel.Panel2)
                        {
                            Panel1.Dock = DockStyle.Fill;
                            Splitter.Dock = DockStyle.Right;
                            Panel2.Dock = DockStyle.Right;
                        }
                        else
                        {
                            Panel1.Dock = DockStyle.Left;
                            Splitter.Dock = DockStyle.Left;
                            Panel2.Dock = DockStyle.Fill;
                        }
                        Splitter.Width = 3;
                    }
                    else
                    {
                        if (FixedPanel == FixedPanel.Panel2)
                        {
                            Panel1.Dock = DockStyle.Fill;
                            Splitter.Dock = DockStyle.Bottom;
                            Panel2.Dock = DockStyle.Bottom;
                        }
                        else
                        {
                            Panel1.Dock = DockStyle.Top;
                            Splitter.Dock = DockStyle.Top;
                            Panel2.Dock = DockStyle.Fill;
                        }
                        Splitter.Height = 3;
                    }
                    ResumeLayout();
                }
            }
        }

        public int SplitterDistance
        {
            get => Orientation == Orientation.Vertical ? Panel1.Width : Panel1.Height;
            set
            {
                if (Orientation == Orientation.Vertical)
                {
                    if (FixedPanel == FixedPanel.Panel1)
                        Panel1.Width = value;
                    else
                        Panel2.Width = Width - value - Splitter.Width;
                }
                else
                {
                    if (FixedPanel == FixedPanel.Panel1)
                        Panel1.Height = value;
                    else
                        Panel2.Height = Height - value - Splitter.Height;
                }
            }
        }

        public FixedPanel FixedPanel
        {
            get => Panel1.Dock != DockStyle.Fill ? FixedPanel.Panel1 : FixedPanel.Panel2;
            set
            {
                if (value == FixedPanel.Panel1)
                {
                    Panel1.Dock = Orientation == Orientation.Vertical ? DockStyle.Left : DockStyle.Top;
                    Splitter.Dock = Panel1.Dock;
                    Panel2.Dock = DockStyle.Fill;
                    Controls.SetChildIndex(Panel1, 2);
                    Controls.SetChildIndex(Panel2, 0);
                }
                else if (value == FixedPanel.Panel2)
                {
                    Panel2.Dock = Orientation == Orientation.Vertical ? DockStyle.Right : DockStyle.Bottom;
                    Splitter.Dock = Panel2.Dock;
                    Panel1.Dock = DockStyle.Fill;
                    Controls.SetChildIndex(Panel1, 0);
                    Controls.SetChildIndex(Panel2, 2);
                }
            }
        }

        public bool Panel1Collapsed
        {
            get => !Panel1.Visible;
            set
            {
                Panel1.Visible = !value;
                Splitter.Visible = !value;
            }
        }

        public bool Panel2Collapsed
        {
            get => !Panel2.Visible;
            set
            {
                Panel2.Visible = !value;
                Splitter.Visible = !value;
            }
        }

        public int SplitterWidth
        {
            get => Orientation == Orientation.Vertical ? Splitter.Width : Splitter.Height;
            set
            {
                if (Orientation == Orientation.Vertical)
                    Splitter.Width = value;
                else
                    Splitter.Height = value;
            }
        }

        public override Color BackColor 
        { 
            get => base.BackColor;
            set
            {
                base.BackColor = value;
                Splitter.BackColor = value;
            }
        }

        public event SplitterEventHandler SplitterMoved;

        protected virtual void OnSplitterMoved(SplitterEventArgs e) => SplitterMoved?.Invoke(this, e);

        public void BeginInit() { }

        public void EndInit() { }

        public SplitContainer()
        {
            SetContentControl(new Windows.Controls.ContentControl());
            
            Panel1 = new SplitterPanel();
            Splitter = new Splitter();
            Splitter.Width = 3;
            Panel2 = new SplitterPanel();

            Controls.AddRange(new Control[] { Panel2, Splitter, Panel1 });
            Orientation = Orientation.Vertical;
            FixedPanel = FixedPanel.Panel1;

            Splitter.SplitterMoved += (s, e) => OnSplitterMoved(e);
        }

    }
}