C# custom search box control library with textbox and list boxt control - Win Form

cText.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

// add user control with a text and list control.  
namespace WindowsFormsControlLibrary
{
    public partial class SText : UserControl
    {
        private string Lwidth = "Auto";
        private bool changed = false;
        private bool defAll = false;
        private List<string> sourceList = new List<string>() { "Apple", "Banana", "Orange", "Anar", "Dragon" };
        private bool tabKeyEnabled = false;
        public SText()
        {
            InitializeComponent();
        }
        [Category("Common")]
        public string BoxText
        {
            get => txt_filter_box.Text; set { txt_filter_box.Text = value; Invalidate(); }
        }        
        public Color BoxBackColor { get => txt_filter_box.BackColor; set { txt_filter_box.BackColor = value; Invalidate(); } }
        public Color ListBackColor { get => listBox_filter.BackColor; set { listBox_filter.BackColor = value; Invalidate(); } }
        public bool TabkeyEnabled { get => tabKeyEnabled; set { tabKeyEnabled = value; Invalidate(); } }
        public int SelectedIndex { get; set; }
        public int SelectedItem { get; set; }
        [Category("Common")]
        public string ListWidth { get => Lwidth; set { Lwidth = value; Invalidate(); } }
        [Category("Data")]
        public List<string> Source
        {
            get { return sourceList; }
            set { sourceList = value; }
        }

        public bool ShowAll { get => defAll; set { defAll = value; Invalidate(); } }

        private void SetBoxHeight(bool list = false)
        {
            try
            {
                if (list)
                {
                    int.TryParse(Lwidth, out int ht);
                    if (ht != 0)
                    {
                        listBox_filter.Height = ht;
                    }
                    this.Height = txt_filter_box.Height + this.Padding.Top + this.Padding.Bottom + listBox_filter.Height;
                    this.Width = txt_filter_box.Width;
                }
                else
                {
                    this.Height = txt_filter_box.Height + this.Padding.Top + this.Padding.Bottom;
                    this.Width = txt_filter_box.Width;
                }
            }
            catch (Exception)
            {

                throw;
            }
        }

        private void SText_Load(object sender, EventArgs e)
        {
            try
            {

                SetBoxHeight();
            }
            catch (Exception)
            {

                throw;
            }
        }

        private void txt_filter_box_TextChanged(object sender, EventArgs e)
        {
            try
            {
                SetBoxHeight();
                if (txt_filter_box.Text.Trim() != "")
                    changed = true;
                listBox_filter.DataSource = null;
                if (txt_filter_box.Text.Trim() == "")
                {

                    if (ShowAll && changed)
                        if (sourceList.Count != 0)
                        {
                            listBox_filter.DataSource = sourceList;
                            SetBoxHeight(true);
                        }

                }
                else
                {
                    listBox_filter.DataSource = null;
                    var ds = sourceList.Where(x => x.ToLower().Contains(txt_filter_box.Text.ToLower())).ToList();
                    if (ds.Count != 0)
                    {
                        listBox_filter.DataSource = ds;
                        SetBoxHeight(true);
                    }

                }
            }
            catch (Exception)
            {

                throw;
            }
        }

        private void BoxKeyPress(object sender, KeyPressEventArgs e)
        {
            try
            {
                if (listBox_filter.Items.Count > 0 && e.KeyChar.Equals((char)Keys.Enter))
                {
                    txt_filter_box.Text = listBox_filter.Text;
                    SetBoxHeight();
                }

                this.OnKeyPress(e);

            }
            catch (Exception)
            {

                throw;
            }
        }

        private void BoxKeyDown(object sender, KeyEventArgs e)
        {
            try
            {
                if (e.KeyCode == Keys.Down)
                {
                    if (listBox_filter.Items.Count != 0)
                        listBox_filter.Focus();
                }
                if (e.KeyCode == Keys.Enter && TabkeyEnabled)
                {
                    SendKeys.SendWait("{tab}");
                    e.Handled = true;
                }
                this.OnKeyDown(e);

            }
            catch (Exception)
            {

                throw;
            }
        }

        private void ListKeyPress(object sender, KeyPressEventArgs e)
        {
            try
            {
                if (e.KeyChar.Equals((char)Keys.Enter))
                {
                    txt_filter_box.Text = listBox_filter.Text.Trim();
                    listBox_filter.DataSource = null;
                    SetBoxHeight();
                    txt_filter_box.Focus();
                }
            }
            catch (Exception)
            {
                throw;
            }
        }

        private void ListKeyDown(object sender, KeyEventArgs e)
        {
            try
            {
                if (e.KeyCode == Keys.Left)
                {
                    txt_filter_box.Focus();

                }
            }
            catch (Exception)
            {

                throw;
            }
        }

        private void BoxEnter(object sender, EventArgs e)
        {
            try
            {
                if (txt_filter_box.Text.Trim().Length == 0)
                {
                    if (ShowAll)
                        if (sourceList.Count != 0)
                        {
                            listBox_filter.DataSource = sourceList;
                            SetBoxHeight(true);
                        }
                }
                txt_filter_box.SelectAll();
                Invalidate();

            }
            catch (Exception)
            {

                throw;
            }
        }

        private void SText_Leave(object sender, EventArgs e)
        {
            SetBoxHeight();
        }
    }
}