SQL insert and Update

Question

hi everyone, when i want to insert sql some value i have a getting “executenonquery connection property has not been initialized” error. but i dont know why ? 

 

everything is clearly code is below

 

anyone have a any idea for this trouble ?

 

for (int i = 0; i < this._blocks.Count; i++)
           {
               if (this._blocks[i].Visible && !string.IsNullOrEmpty(this._blocks[i].Year))
               {

                   string constr = ConfigurationManager.AppSettings["ConnInfo"];
                   using (SqlConnection con = new SqlConnection(constr))
                   {
                       string sql = string.Format(@"IF EXISTS (SELECT * FROM INDUS_OVER_STAT WHERE YEARS = {0}) UPDATE  INDUS_OVER_STAT
                                                   SET
                                                       VAL_1 = {1},
                                                       VAL_2 = {2},
                                                       VAL_3 = {3},
                                                       TARGET_SID = '{4}'
                                                   WHERE    YEARS = {0}
                                                   ELSE
                                                   INSERT    INDUS_OVER_STAT(TARGET_SID, YEARS,VAL_1,VAL_2,VAL_3)
                                                    VALUES    ('{4}', {0},{1},{2},{3})", this._blocks[i].Year, this._blocks[i].MS,this._blocks[i].BNU,this._blocks[i].Emp,this._groupsSId);


                       using (SqlCommand cmd = new SqlCommand(sql))
                       {
                           con.Open();
                           cmd.ExecuteNonQuery();
                           con.Close();
                       }
                   }

               }
           }