Items added to a list multiple times

Question

I'm trying to build a pharmacy project using only c# I wrote a code to diagnose a patient's disease and print the suitible treatment drug for it ,and I want to check if that drug is already in my pharmacy or not(the available drugs are defined in another class) if it exists then the program will pass it to the selling method ,and if it didn't exist I want to add to a list so I can order it later the problem is that every time I run the code it will add all the drugs of all the diseases in that organ system multiple times

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace pharmacy
{
 class OrganSystems
  {
    protected string[,] GastSystem;

   public void GastDefine()
    {
         GastSystem = new string[3, 4];
        GastSystem[0, 0] = "Gastroparesis";
        GastSystem[0, 1] = "-Nausea \n-Vomiting \n-An early feeling of fullness when eating \n-Weight loss " +
            "\n-Abdominal bloating \n-Abdominal discomfort";
        GastSystem[0, 2] = "Premperan";
        GastSystem[0, 3] = "--Follow the doctor's instructions--";

        GastSystem[1, 0] = "Heartburn";
        GastSystem[1, 1] = "-Persistent sore throat \n-Hoarseness \n-Chronic cough \n-Asthma \n-Chest pain " +
            "\n-Feeling like there is a lump in your throat";
        GastSystem[1, 2] = "Salbutamol";
        GastSystem[1, 3] = "--Follow the doctor's instructions--";

        GastSystem[2, 0] = "Acute pancreatitis";
        GastSystem[2, 1] = "-Constant pain in the upper abdomen, in the back and other areas \n-" +
             "Pain may be sudden and intense or may begin as a mild pain that is aggravated by eating and drinking \n-" +
             "Elevated pulse \n-Fever \n-Nausea and vomiting \n-Swollen and tender abdomen";

        GastSystem[2, 2] = "Ganton";
        GastSystem[2, 3] = "--Follow the doctor's instructions--";

    }
}

}

---

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;

      namespace pharmacy
    {
 class Diagnose:Drugs
 {

  public int systemChoice;
    public Diagnose(int SysCh)
    {
        systemChoice = SysCh;
    }



   private int DetermineD;

    public int dDicease
    {
        get { return DetermineD; }
        set { DetermineD = value; }
    }


    public void Symptoms()
    {

        if (systemChoice == 1)
        {
            for (int j = 0; j <= 2; j++)
            {
                Console.WriteLine("{0}:\n {1}\n", j + 1, GastSystem[j, 1]);

            }

            Console.WriteLine("Are you having any of the following? (Type the number)");

            dDicease = int.Parse(Console.ReadLine());
            GastDiagnose();

        }

        else if (systemChoice == 2)
        {
            for (int j = 0; j <= 2; j++)
            {
                Console.WriteLine("{0}:\n {1}\n", j + 1, RespSystem[j, 1]);

            }

            Console.WriteLine("Are you having any of the following? (Type the number)");

            dDicease = int.Parse(Console.ReadLine());
            RespDiagnose();

        }

        else if (systemChoice == 3)
        {
            for (int j = 0; j < 2; j++)
            {
                Console.WriteLine("{0}:\n {1}\n", j + 1, CardSystem[j, 1]);

            }
            Console.WriteLine("Are you having any of the following? (Type the number)");

            dDicease = int.Parse(Console.ReadLine());
            CardDiagnose();


        }

        else if (systemChoice == 4)
        {
            for (int j = 0; j < 2; j++)
            {
                Console.WriteLine("{0}:\n {1}\n", j + 1, EyeSystem[j, 1]);

            }

            Console.WriteLine("Are you having any of the following? (Type the number)");

            dDicease = int.Parse(Console.ReadLine());
            EyeDiagnose();
        }

        else if (systemChoice == 5)
        {
            for (int j = 0; j <= 2; j++)
            {
                Console.WriteLine("{0}:\n {1}\n", j + 1, ENTSystem[j, 1]);

            }

            Console.WriteLine("Are you having any of the following? (Type the number)");

            dDicease = int.Parse(Console.ReadLine());
            ENTDiagnose();
        }
    }




    public void GastDiagnose()
    {

        switch (dDicease)
        {

            case 1:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        GastSystem[0, 0], GastSystem[0, 2], GastSystem[0, 3]); break;
            case 2:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        GastSystem[1, 0], GastSystem[1, 2], GastSystem[1, 3]); break;

            case 3:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        GastSystem[2, 0], GastSystem[2, 2], GastSystem[2, 3]); break;

            default:
                Console.WriteLine("\n\nNOT A VALID ENTRY!\n\nPlease choose the signs that match your state the best\n----------------");

                break;

        }

    }

    public void RespDiagnose()
    {

        switch (dDicease)
        {

            case 1:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        RespSystem[0, 0], RespSystem[0, 2], RespSystem[0, 3]); break;
            case 2:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        RespSystem[1, 0], RespSystem[1, 2], RespSystem[1, 3]); break;

            case 3:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        RespSystem[2, 0], RespSystem[2, 2], RespSystem[2, 3]); break;

            default:
                Console.WriteLine("\n\nNOT A VALID ENTRY!\n\nPlease choose the signs that match your state the best\n----------------");
                Symptoms();
                break;

        }

    }


    public void CardDiagnose()
    {

        switch (dDicease)
        {

            case 1:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        CardSystem[0, 0], CardSystem[0, 2], CardSystem[0, 3]); break;
            case 2:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        CardSystem[1, 0], CardSystem[1, 2], CardSystem[1, 3]); break;

            default:
                Console.WriteLine("\n\nNOT A VALID ENTRY!\n\nPlease choose the signs that match your state the best\n----------------");
                Symptoms();
                break;

        }

    }




    public void ENTDiagnose()
    {

        switch (dDicease)
        {

            case 1:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        ENTSystem[0, 0], ENTSystem[0, 2], ENTSystem[0, 3]); break;
            case 2:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        ENTSystem[1, 0], ENTSystem[1, 2], ENTSystem[1, 3]); break;

            case 3:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        ENTSystem[2, 0], ENTSystem[2, 2], ENTSystem[2, 3]); break;

            default:
                Console.WriteLine("\n\nNOT A VALID ENTRY!\n\nPlease choose the signs that match your state the best\n----------------");
                Symptoms();
                break;

        }

    }

     public void EyeDiagnose()
    {

        switch (dDicease)
        {

            case 1:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        EyeSystem[0, 0], EyeSystem[0, 2], EyeSystem[0, 3]); break;
            case 2:
                Console.WriteLine("Dicease: {0}\nTreatment: {1}\nDrug: {2}\n\n-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-",
                        EyeSystem[1, 0], EyeSystem[1, 2], EyeSystem[1, 3]); break;


            default:
                Console.WriteLine("\n\nNOT A VALID ENTRY!\n\nPlease choose the signs that match your state the best\n----------------");
                Symptoms();
                break;

        }

    }

     public List<string> ToBeOrdered = new List<string>();

     Drugsoperation ON;

     public void MatchingMed()
     {
         getdrugs();
         foreach (Druginformation drugInfo in Definnewdrugs)
         {
             for (int i = 0; i < 3; i++) 
             {
                 if (systemChoice == 1 && GastSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     ON = new Drugsoperation(GastSystem[i, 2]);
                     ON.order();
                     break;
                 }
                 else if (systemChoice == 1 && !GastSystem[i, 2].Contains(drugInfo.Drugname))

                     Console.WriteLine("This medicine is not available now, but we will make sure to have it soon.");
                 if (ToBeOrdered.Count < 2)
                 {
                     ToBeOrdered.Add(GastSystem[i, 2]);
                 }
             }

             for (int i = 0; i < 3; i++)
             {

                 if (systemChoice == 2 && RespSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     ON = new Drugsoperation(RespSystem[i, 2]);
                     ON.order();

                 }
                 else if (systemChoice == 2 && !RespSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     Console.WriteLine("This medicine is not available now, but we will make sure to have it soon.");
                     ToBeOrdered.Add(RespSystem[i, 2]);
                 }

             }

             for (int i = 0; i < 2; i++)
             {


                 if (systemChoice == 3 && CardSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     ON = new Drugsoperation(CardSystem[i, 2]);
                     ON.order();
                 }
                 else if (systemChoice == 3 && !CardSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     Console.WriteLine("This medicine is not available now, but we will make sure to have it soon.");
                     ToBeOrdered.Add(CardSystem[i, 2]);
                 }
             }


             for (int i = 0; i < 2; i++)
             {

                 if (systemChoice == 4 && EyeSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     ON = new Drugsoperation(EyeSystem[i, 2]);
                     ON.order();

                 }
                 else if (systemChoice == 4 && !EyeSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     Console.WriteLine("This medicine is not available now, but we will make sure to have it soon.");
                     ToBeOrdered.Add(EyeSystem[i, 2]);
                 }

             }

             for (int i = 0; i < 3; i++)
             {


                 if (systemChoice == 5 && ENTSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     ON = new Drugsoperation(ENTSystem[i, 2]);
                     ON.order();

                 }
                 else if (systemChoice == 5 && !ENTSystem[i, 2].Contains(drugInfo.Drugname))
                 {
                     Console.WriteLine("This medicine is not available now, but we will make sure to have it soon.");
                     ToBeOrdered.Add(ENTSystem[i, 2]);
                 }
             }
         }    

     }


     public void PrintOrders()
     {

         Console.WriteLine("Medicines to be ordered:");
         foreach (string OMed in ToBeOrdered)
         {
             Console.WriteLine(OMed);
         }

     }
  }
}

the output is

Answer 1

What you want is to check the list to see if it contains the string already. This is easily done with:

// If the list of drugs to be ordered does not contain this drug name
if(!ToBeOrdered.Contains("DrugNameGoesHere")
{
    // Then, add this drug name to the list.
    ToBeOrdered.Add("DrugNameGoesHere");
}

You can read more on Contains here: http://www.dotnetperls.com/list-contains

Answer 2

This code is such a mess. With some kind of dark magic make sense of this project. If you have a list, use linq to get only unique names.

list = list.GroupBy(x => x.DrugName).Select(x => x.First()).ToList();