C#中对象名无效

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public int NowPage = 1, PageCount = 1, PageSize = 5;
public string AddSql="";

private void findbtn_Click(object sender, EventArgs e)
{
string FindStr = findstr.Text;
if (FindStr != "") AddSql = "where(UserName like '%" + FindStr + "%' or Address like '%" + FindStr + "%' or Email like '%" + FindStr + "%')";
NowPage = 1;
PageCount = 1;
LoadData(sender, e);
}

private void p_btn_Click(object sender, EventArgs e)
{
NowPage--;
LoadData(sender, e);
}

private void n_btn_Click(object sender, EventArgs e)
{