C#一次性清空TextBox或者将某一类控件置某一状态

1. #region 清除
2.     protected void btnClear_Click(object sender, EventArgs e)
3.     {
4.         foreach (Control ctl in this.Controls)
5.         {
6.             this.txtClear(ctl);
7.         }
8.     }
9.     #endregion
11.     private void txtClear(Control ctls)
12.     {
13.         if(ctls.HasControls())
14.         {
15.             foreach (Control ctl in ctls.Controls)
16.             {
17.                 txtClear(ctl);
18.             }
19.         }
20.         else
21.         {
22.             if (ctls.GetType().Name == "TextBox")
23.             {
24.                 TextBox tb = new TextBox();
25.                 tb = (TextBox)this.FindControl(ctls.ID);
26.                 tb.Text = "";
27.             }
28.             else if (ctls.GetType().Name == "DropDownList")
29.             {
30.                 DropDownList ddl = new DropDownList();
31.                 ddl = (DropDownList)this.FindControl(ctls.ID);
32.                 ddl.SelectedIndex = 1;
33.             }
34.         }
35.     }