How to read data from database and store it in array

Question

User1006710852 posted

I am uisng asp.net 3.5 with c# as language. I want to read the database and store the data in either array or arraylist so that it can be called further in a dropdown list. How to proceed, pls give me some idea

Answer 1

User-1373473781 posted

First make one class having similar attribute as you database table for eg:
        public class Student
        {
            public int ID { get; set; }
            public string Name { get; set; }
            public DateTime DateOfBirth { get; set; }

        }
after that
            List<Student> student = new List<Student>();
            SqlConnection conn = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\Prac\TestAssembly\ForumsProjectCSharp\App_Data\Studetnt.mdf;Integrated Security=True;User Instance=True");
            SqlCommand cmd = new SqlCommand("select * from Student", conn);
            SqlDataReader dr;
            try
            {
                conn.Open();
                dr = cmd.ExecuteReader();
                while (dr.Read())
                {
                    student.Add(new Student()
                    {
                        ID = dr.GetInt32(dr.GetOrdinal("ID")),
                        Name = dr.GetString(dr.GetOrdinal("Name")),
                        DateOfBirth = dr.GetDateTime(dr.GetOrdinal("DateOfBirth"))
                    });
                    
                }
                dr.Close();
            }
            catch (Exception exp)
            {

                throw;
            }
            finally 
            {
                
                conn.Close();
            }

Try this

Answer 2

User1992938117 posted

it can be called further in a dropdown list.

so why not you are binding dropdowllist directly:

SqlConnection con = new SqlConnection("Server=CRC;Database=ABCD;Trusted_Connection=True");
SqlCommand cmd = new SqlCommand("Select State from STATE");

SqlDataAdapter objAdapter=new SqlDataAdapter();

DataSet dset=new DataSet 
objAdapter.selectCommand=cmd;

objAdapter.Fill(dset,"state");

con.close();
dropdownlist1.DataSource=dset.Tables[0];

dropdownlist1.DataTextField=dset.Tables[0].Columns[0].ToString()

dropdownlist1.DataValueField=dset.Tables[0].Columns[0].ToString();
 dropdownlist1.dataBind();

Answer 3

User542821068 posted

           
            int[] _myArr = new int[NUMBER];

where number is the field which u have fetched from database

Answer 4

User-1706566334 posted

Hi,

 

using DataTable retreview the data from Table, then create array list, convert the datatable value to string using " , ", then using split u can load the array list, if u load the value in DropDown list mean y u using Array List, from Data Table to Drop Down List u can directly load. no need for array list.

EG Using Array:

DataTable DT=new DataTable();
string[] arr;
if(DT.Rows.Count>0)
  {
       string StrArray = string.Join(",", (from DataRow row in DT.Rows select (string)row["DataTableColumnName"]).ToArray());
       arr = StrArray.Split(',');
   }