how to use multidimensional array using C#

Question

How can i read multiple column values into an array list? I am trying to read a list of category names and category ids from database into an array list; i am then binding these values into drop-down list. With my current code, i am able to do with one column only but would like to pull both cat_name and cat_id so how can i do that?

 <asp:DropDownList ID="DropDownList1" runat="server"  DataTextField="ct_name" DataValueField="ct_id" AppendDataBoundItems="true">
            <asp:ListItem Value="-1">Select</asp:ListItem>
            </asp:DropDownList>

here is code behind

 private ArrayList GetDummyData()
 {
     ArrayList arr = new ArrayList();
     string strConn = ConfigurationManager.ConnectionStrings["myCon"].ConnectionString.ToString();
     SqlConnection con = new SqlConnection(strConn);
     con.Open();
     SqlCommand cmd = new SqlCommand("select distinct ct_name, cat_id from [myTable].[dbo].[categories]", con);
     SqlDataReader objDR = cmd.ExecuteReader();

     if (objDR != null) {
         while (objDR.Read())
         {
             //fill arraylist
             arr.Add(objDR["ct_name"]);
         }
     }

     con.Close();
     return arr;
 }

 private void FillDropDownList(DropDownList ddl)
 {
     ArrayList arr = GetDummyData();
     foreach (string item in arr)
     {
         ddl.Items.Add(item);
     }
}

maybe you should use a Dictionary<int,string>, dic.Add(Convert.ToInt32(objDR["cat_id"]),objDR["ct_name"]) — DanielVorph
– DanielVorph, Commented Jun 19, 2015 at 16:14
Side note: in most cases best use of multidimensional array (like int[10,10]) is not to... Also it does not look like you have even single array - ArrayList is not an "array" and generally obsolete (use List<T> instead). — Alexei Levenkov
– Alexei Levenkov, Commented Jun 19, 2015 at 16:15
Why don't you replace using the reader and just return a DataTable? You can bind the Rows to your DropDownList. Your DataTexField and DataValueField are set correctly already. Otherwise you should do ddl.Items.Add(new ListItem(objDR["ct_name"], objDR["ct_id"])); No need for a temporary list of objects. — Dacker
– Dacker, Commented Jun 19, 2015 at 16:22

Alexei Levenkov · Accepted Answer · 2015-06-19 16:19:51Z

3

Best way to use "multidimensional array" is commonly not to use one and instead use strongly typed data:

class Category
{
  public string Name {get;set;}
  public string Id {get;set;}
}

List<Category> categories = new List<Category>();
while (objDR.Read())
{
    categories.Add(new Category { 
       Name = objDR["ct_name"],
       Id =  objDR["ct_id"],
    };
}

answered Jun 19, 2015 at 16:19

Alexei Levenkov

101k15 gold badges138 silver badges189 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Blaargon · Accepted Answer · 2015-06-19 16:23:07Z

1

If you're trying to put both items in the dropdownlist side by side, then you could use

SELECT concat(cat_id," ", ct_name) ...

answered Jun 19, 2015 at 16:23

Blaargon

886 bronze badges

Collectives™ on Stack Overflow

how to use multidimensional array using C#

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related