ASP.net(c#)字符串替换简单例子

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
String str = "<>>";
String b = cleanStr(str);
this.Label1.Text=b;

}
public string cleanStr(String str)
{
StringBuilder bs = new StringBuilder(str);
bs = bs.Replace("<","<");
bs = bs.Replace(">", ">");
return bs.ToString();
}

}