asp.NET中,密码输入框一刷新后输入的密码就清空,但刷新后保留刷新前输入的密码怎么做?

在事件中赋值

 /// <summary>
    /// 属性改变时
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void txtPassWord_TextChanged(object sender, EventArgs e)
    {
        txtPassWord.Attributes["value"] = txtPassWord.Text;
    }