how to declare global function or method using c#?

Question

Can anyone tell me how to declare a global function in c#, similar to what a Module does in VB.net? I need to call a function that can be called in my form1, fo

Answer 1

@kol is right, there are NO global functions in C#. Take a look at this post MSDN post. I would use layers (I renamed your "Module" class to "TransactionsModule") and It would look like this:

using System;
using System.Collections.Generic;
using System.Data.OleDb;

namespace XYZ
{
    public class TransactionsModule
    {
        public List GetPersons(string query, string connectionString)
        {
            List dbItems = new List();

            OleDbConnection conn = new OleDbConnection(connectionString);

            try 
            {
                conn.Open();
                var cmd = new OleDbCommand(query, conn);
                cmd.CommandText = query;

                using (OleDbDataReader reader = cmd.ExecuteReader())
                {
                    Person objPerson = new Person();

                    //These are the columns returned
                    objPerson.Name = Convert.ToString(myReader["Name"]);
                    objPerson.Age = Convert.ToInt32(myReader["Age"]);

                    dbItems.Add(objPerson);
                }
            } 
            catch(OleDbException ex)
            {
                throw ex;
            }
            finally
            {
                conn.Close();
            }
            return dbItems;           
        }


    }

    //This class should be in another Layer, but I placed it here since It's a quick Example
    public class Person
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }
}

All the logic was abstracted to the TransactionsModule class, then you only need to call the Method: GetPersons. Take a look:

using System;
using System.Collections.Generic;
using XYZ.TransactionsModule;

namespace XYZ
{
    public partial class frmReports : Form
    {      
        public frm1()
        {
            InitializeComponent();
            protected TransactionsModule moduleTran;
        }

        private void frm1_Load(object sender, EventArgs e)
        {
            //We initialize the Data Access Layer class
            moduleTran = new TransactionsModule();

            //This ConnectionString should be in your app.config
            string conString = "provider= microsoft.jet.oledb.4.0;data source=..\\dbCooperative.mdb";
            string sqlQuery = "SELECT * FROM table";

            List ItStaff = moduleTran.GetPersons(sqlQuery, conString);
        }
    }
}