更改动态创建的按钮的背景

Question

我创建了一些按钮，当用户单击按钮时它会改变背景颜色，但是当用户按下另一个按钮时我需要将背景颜色更改为默认颜色

        max = Service.Max_id();
        max = max - 1;

        for (int i = 0; i < max; i++)
        {
            int x = i + 1;
            string num = (i + 1).ToString();

            DataTable dt = Service.fillWid((i + 1).ToString());
            string titlee = "";
            titlee = dt.Rows[0]["name"].ToString();

            ckplaceat = new Button();

            ckplaceat.ID = titlee;
            ckplaceat.Text = titlee;

            ckplaceat.Click += new EventHandler(ButtonClickOneEvent);


            ckplaceat.Style["Width"] = "115px";
            // ckplaceat.BackColor = Color.LightGray;
            ckplaceat.CssClass = "wButton";

            PlaceHolder1.Controls.Add(ckplaceat);
            PlaceHolder1.Controls.Add(new LiteralControl(" "));


            //PlaceHolder1.Controls.Add(new LiteralControl("<br/>"));

        }

protected void ButtonClickOneEvent(object sender, EventArgs e)
        {

            ckplaceat.BackColor = default(Color);
            btn = (Button)sender;

            btnclicked = (sender as Button).ID;

            for (int i = 0; i < max; i++)
            {
                idFunction();
              // changecolor();
                widgetChangeFun();
                btn.BackColor = Color.Black;
            }