protected void Button1_Click(object sender, EventArgs e)
    {
        string search = "";
        if (!string.IsNullOrEmpty(TextBox2.Text))
        {
            search += "and Uname like'%" + Common.ForamatParameter(TextBox2.Text) + "%'";
        }
        string Sql="select*from kaoqin";
        PageNavigator1.Total = 1;
        PageNavigator1.Query = Sql;
        
    }

不存在，那你怎么写错来了呢？

 string search = "";
        if (!string.IsNullOrEmpty(TextBox2.Text))
        {
            search += "and Uname like'%" + Common.ForamatParameter(TextBox2.Text) + "%'";
        }
        string Sql="select*from kaoqin";

加红的Common 你哪来的。。。

还有 string Sql="select*from kaoqin"; ===》string Sql="select * from kaoqin";（别老是忘记空格）