How to create an arrays Arraylist?

Question

I’m having some problems creating a list of arrays, I’m using Visual C#, . NET 3.5.

Code:

using Database;
//...
namespace Sample {
    public partial class Form1 : Form {
        //...
        private void Button1_Click(object sender, EventArgs e) {
            if ((TextBox1.Text).Equals("") || (TextBox2.Text).Equals("")) {
                MessageBox.Show(null, "Preencha todos os campos!", "Erro");
            } else {
                ClassDatabase Call = new ClassDatabase();
                Call.RegDatabase(TextBox1.Text, TextBox2.Text);
                //...
            }
        }
        //...
    }
}

namespace Database {
    class ClassDatabase {
        List<string[]> InfoList = new List<string[]>();
        public void RegDatabase(String A, String B) {
            string[] DataSet = new string[2];
            DataSet[0] = A;
            DataSet[1] = B;
            this.InfoList.AddRange(DataSet);
        } public bool InDatabase (String A, String B) {
            int j = InfoList.Count;
            for (int i = 0; i < j; i ++) {
                string[] DataGet = new string[2];
                DataGet = this.InfoList[i];
                if (DataGet[0].Equals(A) && DataGet[1].Equals(B)) {
                    return true;
                } else {
                    return false;
                }
            }
        }
    }
}

using Database;
//...
namespace Sample {
    public partial class Form2 : Form {
        //...
        ClassDatabase Call = new ClassDatabase();
        private void Button1_Click(object sender, EventArgs e) {
            if (Call.InDatabase(TextBox1.Text, TextBox2.Text)) {
                //...
            } else {
                MessageBox.Show(null, "Falha ao entrar.", "Erro");
            }
        }
        //...
    }
}

What was supposed to happen there is a record, then a validation.

The user registers and presses the button to confirm, the information is sent to the method RegDatabase class ClassDatabase, adding that information to the type list string[], InfoList. When the user tries to enter, he puts the information in the Textbox and click the button, this sends the information to the other method of the class ClassDatabase, the InDatabase, this method takes the list InfoList and opens each array by comparing the data of each array within the list InfoList with the data entered by the user; if the condition of the if, the method returns true and enters the system, if not, returns false and this generates an error message.

Well, that’s what I tried to make it happen, but it’s not what happens, the problem, perhaps, is my lack of experience, but anyway, as I could do the above?

Is there any more practical way to make this record/validation (DLL, for example)? If so, which?

Answer 1

I noticed that your class presented some coding errors, I made the changes on your code and it was like this:

1) Option

Code

    public class ClassDatabase
    {
        protected List<string[]> InfoList = new List<string[]>();
        public void RegDatabase(String A, String B)
        {
            InfoList.Add(new String[2] { A, B });
        }
        public bool InDatabase(String A, String B)
        {
            bool ret = false;            
            int i = 0;
            while (ret == false && i < InfoList.Count)
            {
                if (InfoList[i] != null)
                {
                    if (A.Equals(InfoList[i][0]) && 
                        B.Equals(InfoList[i][1]))
                    {
                        ret = true;
                    }                    
                }
                i++;
            }
            return ret;
        }
    }

How to use

ClassDatabase db = new ClassDatabase();
//ADICIONANDO VALORES
db.RegDatabase("Valor1", "Valor2");
db.RegDatabase("Valor3", "Valor4");

//VERIFICANDO SE O VALOR EXISTE
bool ret = db.InDatabase("Valor3", "Valor4");

Debugging

Note: Notice that it is working and he found the value inside the List<String[]> !!!

---

2) Option

Another way with data persistence until program closure

Code

public static class ClassDatabase
{
    static ClassDatabase()
    {
        ClassDatabase.InfoList = new List<string[]>();
    }
    public static List<string[]> InfoList { get; private set; }
    public static void RegDatabase(String A, String B)
    {
        InfoList.Add(new String[2] { A, B });
    }
    public static bool InDatabase(String A, String B)
    {
        bool ret = false;
        int i = 0;
        while (ret == false && i < InfoList.Count)
        {
            if (InfoList[i] != null)
            {
                if (A.Equals(InfoList[i][0]) &&
                    B.Equals(InfoList[i][3]))
                {
                    ret = true;
                }
            }
            i++;
        }
        return ret;
    }
}

How to use

Form1 will be responsible for filling it the first time.

private void Form1_Load(object sender, EventArgs e)
{            
       //ADICIONANDO VALORES
       ClassDatabase.RegDatabase("Valor1", "Valor2");
       ClassDatabase.RegDatabase("Valor3", "Valor4");
       ClassDatabase.RegDatabase("Valor5", "Valor6");
       ClassDatabase.RegDatabase("Valor7", "Valor8");
}

Form2 (or any form) can view the added values until the program closes.

private void Form2_Load(object sender, EventArgs e)
{
   //ClassDatabase.InDatabase
   //ClassDatabase.RegDatabase
}

Reference:

• Static (C# Reference)

• Static Classes and Static Class Members (C# Programming Guide)