复选框.Visible=false；但它还在吗

我在C#中有一个数据列表，其中有很多复选框和名字。单击按钮时，首先，表中的所有数据都将被删除，对于选中的每个复选框，ID都将再次插入到选项卡中。这很有效。

问题是当我只显示某些复选框时，例如名字是John。显示所有带有ID的复选框，但只有包含John的复选框可见。如果我再选中几个复选框并单击按钮，那么所有行都将被删除，然后我的想法是可见的复选框=false；Stil在那里，正在被再次插入。但他们不是。。。

有没有其他方法可以让它像我想要的那样工作？

    protected void Page_Load(object sender, EventArgs e)
{
    GetEmployee();
    CompareEmployee();
}
private void GetEmployee()
{
string FirstName = table.Rows[i]["FirstName"].ToString();
string qs = (Request.QueryString["search"].ToString());

 DataTable table = SearchPerson(search);
 for (int i = 0; i < table.Rows.Count; i++)
    {
        CheckBox checkbox = new CheckBox();
        checkbox.ID = table.Rows[i]["UserID"].ToString();
        checkbox.Visible = false;
        HyperLink hlFirstName = new HyperLink();
        hlFirstName.Text = table.Rows[i]["FirstName"].ToString();            
        hlFirstName.Visible = false;

        string FirstName = table.Rows[i]["FirstName"].ToString();            
        string qs = (Request.QueryString["search"].ToString());
        if (qs.Contains(FirstName))
        {
            checkbox.Visible = true;
            hlFirstName.Visible = true;                
        }
        phEmployee.Controls.Add(checkbox);
        phEmployee.Controls.Add(hlFirstName);
    }
}
private void CompareEmployee()
{
    int UserID = ((User)Session["LoggedInUser"]).UserID;
    DataTable table = new DataTable();
    table = GetEmployee(UserID);
    foreach (Control c in phEmployee.Controls)
    {
        if (c.GetType() == typeof(CheckBox))
        {
            for (int i = 0; i < table.Rows.Count; i++)
            {
                if (c.ID == table.Rows[i][0].ToString())
                {
                    (c as CheckBox).Checked = true;
                }
            }
        }
    }
}
protected void btnUpdate_Click(object sender, EventArgs e)
{
    int UserID = ((User)Session["LoggedInUser"]).UserID;
    {            
        DeleteEmployee(UserID);
        foreach (Control c in phEmployee.Controls)
        {
            if (c.GetType() == typeof(CheckBox))
            {
                if ((c as CheckBox).Checked)
                {
                    AddEmployee(c.ID, UserID);
                }
            }
        }
        Response.Redirect("Default.aspx");
    }
}

var chk = c as CheckBox;
if( c != null )
{
    AddEmployee(c.ID, UserID);
}