input string was not incorrect format

private void BindGrid()
   {
       try
       {
           lblmsg.Text = "";


           incharge inch = new incharge();
           //DataTable dt = inch.SearchinchargeRecords()'
           DataTable dt = inch.Searchincharge( Convert.ToInt32(ddlcon.SelectedValue), Convert.ToInt32(ddlstate.SelectedValue), Convert.ToInt32(ddldistrict.SelectedValue), Convert.ToInt32(ddlblock.SelectedValue), Convert.ToInt32(ddldesignation.SelectedValue), txtname.Text, txtfathername.Text, Convert.ToInt32(txtinsanno.Text), Convert.ToInt32(txtmobileno.Text) );

           GridView1.DataSource = dt;
           GridView1.DataBind();

           lblcount.Text = "Total Records = " + dt.Rows.Count;

       }
       catch (Exception ex)
       {
           lblmsg.Text = "Error! " + ex.Message;
       }
   }

public DataTable Searchincharge(int countryid, int stateid, int districtid, int blockid, int designationid, string name, string fathername, int insanno, int mobileno)
   {
       CountryId = countryid;
       StateCountryId = stateid;
       DistrictStateId = districtid;
       BlockDistrictId = blockid;
       DesignationId = designationid;
       Name = name;
       FatherName = fathername;
       InsanNo = insanno;
       MobileNo = mobileno;

       try
       {
           string qry = "select * from inchargedetail inch left join country c on inch.country=c.countryid left join state s on inch.state=s.stateid left join district distt on inch.district=distt.districtid left join block b on inch.block=b.blockid left join designation d on inch.designation=d.designationid where 1 = 1";
           MySqlParameter countryidP, stateidP, districtidP, blockidP, designationidP, nameP, fathernameP, insannoP, mobilenoP;
           MySqlParameter[] p = { };
           if (countryid != 0)
           {
               qry += " and inch.country = @countryid";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               countryidP = new MySqlParameter("@countryid", CountryId);
               p[p.Length - 1] = countryidP;
           }
           if (StateCountryId != 0)
           {
               qry += " and inch.state = @statecountryid";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               stateidP = new MySqlParameter("@statecountryid", StateCountryId);
               p[p.Length - 1] = stateidP;
           }
           if (DistrictStateId != 0)
           {
               qry += " and inch.district = @districtstateid";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               districtidP = new MySqlParameter("@districtstateid", DistrictStateId);
               p[p.Length - 1] = districtidP;
           }
           if (BlockDistrictId != 0)
           {
               qry += " and inch.block = @blockdistrictid";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               blockidP = new MySqlParameter("@blockdistrictid", BlockDistrictId);
               p[p.Length - 1] = blockidP;
           }
           if (designationid != 0)
           {
               qry += " and inch.designation=@designationid";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               designationidP = new MySqlParameter("@designationid", DesignationId);
               p[p.Length - 1] = designationidP;
           }

           if (name != "")
           {
               qry += " and inch.inchargename=@name";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               nameP = new MySqlParameter("@name", Name);
               p[p.Length - 1] = nameP;
           }

           if (fathername != "")
           {
               qry += " and inch.fathername=@fathername";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               fathernameP = new MySqlParameter("@fathername", FatherName);
               p[p.Length - 1] = fathernameP;
           }

           if (insanno > 0)
           {
               qry += " and inch.insanno=@insanno";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               insannoP = new MySqlParameter("@insanno", InsanNo);
               p[p.Length - 1] = insannoP;
           }

           if (mobileno > 0)
           {
               qry += " and inch.mobileno=@mobileno";
               Array.Resize<MySqlParameter>(ref p, p.Length + 1);
               mobilenoP = new MySqlParameter("@mobileno", MobileNo);
               p[p.Length - 1] = mobilenoP;
           }

           return MySqlHelper.ExecuteDataset(common.GetConnectionString(), qry, p).Tables[0];

       }
       catch
       {
           Exception ex = new Exception("Search InchargeDetail Error.");
           throw ex;
       }


   }