An exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll but was not handled in user code Additional information: Invalid object name 'Attendence1'.

protected void Stor_Click(object sender, EventArgs e)
    {
        string s1 = "p1";
        DataTable dt = new DataTable();
        dt.Columns.Add("UID");
        dt.Columns.Add("Name");
       
        con.Open();
        foreach (GridViewRow item in GridView1.Rows)
        {
            if ((item.Cells[0].FindControl("CheckBox1") as CheckBox).Checked)
            {
                DataRow dr = dt.NewRow();
                dr["UID"] = item.Cells[0].Text;
                dr["Name"] = item.Cells[1].Text;
                dt.Rows.Add(dr);
                Response.Write(dr["UID"].ToString());
                Response.Write(dr["Name"].ToString());
                int t1 = Convert.ToInt32(dr["UID"].ToString());
                string query = "Update Attendence1 set Status='" + s1 + "' where UID=" + t1 + "";
                SqlCommand cmd = new SqlCommand(query, con);
                cmd.ExecuteNonQuery();
               
            }
        }
        
        
    }