public partial class Form1 : Form
    {
        private Point _defaultLocation;
 
        private Thread _trd;
        private delegate void MoveTextBoxDelegate();
        private volatile bool _canceled = false;
 
        public Form1()
        {
            InitializeComponent();
 
            this._defaultLocation = this.textBox1.Location;
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            //既に移動処理中か？
            if (this._trd != null && this._trd.IsAlive)
            {
                //移動処理を途中で終わらす
                //this._trd.Abort(); //意図した動きをしないため使用しない
                this._canceled = true;
                this._trd.Join(); //!!! Application.DoEventsで止まっているためデッドロック発生 !!!
                this._canceled = false;
            }
 
            //移動処理用スレッドをスタートする
            this._trd = new Thread(MoveTextBoxWorker);
            this._trd.IsBackground = true;
            this._trd.Start();
        }
 
        private void MoveTextBoxWorker()
        {
            this.Invoke(new MoveTextBoxDelegate(MoveTextBox));
        }
 
        /// <summary>
        /// 移動処理メソッド
        /// </summary>
        private void MoveTextBox()
        {
            Int32 moveDistance = 1;
 
            this.textBox1.Location = this._defaultLocation;
 
            while (this.textBox1.Location.X <= this.Width)
            {
                this.textBox1.Location = new Point(this.textBox1.Location.X + moveDistance, this.textBox1.Location.Y);
                this.textBox1.Update();
 
                moveDistance = moveDistance * 2;
                Thread.Sleep(100);
 
                Application.DoEvents(); //途中でもbutton1_Clickイベントを割り込ますため
 
                if (this._canceled)
                {
                    break;
                }
            }
        }
 
        /// <summary>
        /// デバッグ用の情報が入っているtextBox1のTextをクリアする。
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            this.textBox1.Clear();
        }
    }

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