3rdpartylibs/fastreports.wpf/FastReport.DesignExt/Controls/SearchBox.cs

using System;
using System.Drawing;
using System.Windows.Forms;

namespace FastReport.Controls
{
    internal class SearchBox : TextBoxButton
    {
        private string emptyText;
        private string saveText;

        public string EmptyText
        {
            get => emptyText;
            set
            {
                emptyText = value;
                if (TextBox.Text == "")
                    TextBox.Text = value;
            }
        }

        public override string Text
        {
            get => TextBox.Text == EmptyText ? "" : TextBox.Text;
            set => TextBox.Text = value == "" ? EmptyText : value;
        }

        public event EventHandler Search;

        protected virtual void OnSearch(EventArgs e)
        {
            saveText = Text;
            Search?.Invoke(this, e);
        }

        private void textBox_GotFocus(object sender, EventArgs e)
        {
            if (TextBox.Text == EmptyText)
                TextBox.Text = "";
            saveText = Text;
        }

        private void textBox_LostFocus(object sender, EventArgs e)
        {
            var timer = new Timer() { Interval = 50, Enabled = true };
            timer.Tick += (s, args) =>
            {
                if (!Button.Focused)
                    Text = saveText;
                timer.Dispose();
            };
        }

        private void textBox_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar == (char)13)
            {
                e.Handled = true;
                OnSearch(e);
            }
            else if (e.KeyChar == (char)27)
            {
                e.Handled = true;
                TextBox.Text = saveText;
            }
        }

        public SearchBox()
        {
            Button.BackColor = SystemColors.Window;
            ButtonClick += (s, e) =>
            {
                OnSearch(e);
            };
            TextBox.GotFocus += textBox_GotFocus;
            TextBox.LostFocus += textBox_LostFocus;
            TextBox.KeyPress += textBox_KeyPress;
            TextBox.PreviewKeyDown += (s, e) =>
            {
                if (e.KeyCode == Keys.Escape)
                    e.IsInputKey = true;
            };
        }
    }
}