如何将例遍控件大方法写成类？

[live533]

这是一个将页面的textbox的text值清空的方法，怎么把他写成类文件？

public class qt
{
private void ClearControl()
{
foreach (System.Web.UI.Control control in 这个地方？怎么写啊？)
{
for (int i = 0; i < control.Controls.Count; i++)
{
if (control.Controls[i] is System.Web.UI.WebControls.TextBox)
{
System.Web.UI.WebControls.TextBox tb = (System.Web.UI.WebControls.TextBox)control.Controls[i];
tb.Text = "";
}
}
}

}

}

[wuyq11]

private void ClearControl(Page p)
{
foreach (System.Web.UI.Control c in p.Controls)
{
if (c.GetType().ToString().Equals("System.Web.UI.WebControls.TextBox")) {
System.Web.UI.WebControls.TextBox tb = (System.Web.UI.WebControls.TextBox)control.Controls[i];
tb.Text = "";
}
}
}

}

[wuyq11]

private void ClearControl(Control c)
{
foreach (Control childControl in c.Controls)
{
if (childControl is TextBox)
((TextBox)childControl).Text = "";
else
test(childControl);
}
}调用时用:
test(this.Page)