convert ArrayList object to double

[Web learner]

In the following code, I want ArrayList object x to be of type double.

How can I do that?

--Thanks

SqlConnection objConnection = new
SqlConnection(" server=(local)\ \SQLEXPRESS; database=Northw ind; integrated
security=true;" );
String strSQL = "SELECT ProductName, UnitsInStock FROM Products
WHERE UnitsInStock >= 50";
SqlCommand objCommand = new SqlCommand(strS QL, objConnection);

objConnection.O pen();

ArrayList strLabel = new ArrayList();
ArrayList x = new ArrayList();

SqlDataReader dr = objCommand.Exec uteReader();

while (dr.Read())
{
object[] values1 = new object[0];
dr.GetValues(va lues1);
strLabel.Add(va lues1);

object[] values2 = new object[1];
dr.GetValues(va lues2);
x.Add(values2);
}

dr.Close();
objConnection.C lose();

[Web learner]

Thanks for your helps. I have modified the code and attach it at the bottom of this message.

At line unitsInStock.Ad d((double)dr.Ge tValue(1)); I still get same error: Specified cast is not valid

If you comment out above code line and also Response.Write( unitsInStock[0]);
then the code works fine. That means it works for productName array.

My purpose is to populate an array from SqlDataReader as below:

double[] unitsInStock = { 120, 104, 112, 111 };
string[] productName = { "Boysenberr y", "Something" , "Another item", "Demo item" };
--------------------------------------------

<%@ Import Namespace="Syst em.Data" %>
<%@ Import Namespace="Syst em.Data.SqlClie nt" %>
<%@ Import Namespace="Syst em.Web.UI" %>
<%@ Import Namespace="Syst em.Collections. Generic" %>
<script language="c#" runat="server">
private void Page_Load(objec t sender, System.EventArg s e)
{
SqlConnection objConnection = new SqlConnection(" server=(local)\ \SQLEXPRESS; database=Northw ind; integrated security=true;" );
String strSQL = "SELECT productName, unitsInStock FROM Products WHERE unitsInStock >= 100";
SqlCommand objCommand = new SqlCommand(strS QL, objConnection);
objConnection.O pen();

SqlDataReader dr = objCommand.Exec uteReader();

List<string> productName = new List<string>();
List<double> unitsInStock = new List<double>();

while (dr.Read())
{
productName.Add ((string)dr.Get Value(0)); //No Error
unitsInStock.Ad d((double)dr.Ge tValue(1)); //ERROR : Specified cast is not valid
}
dr.Close();
objConnection.C lose();

Response.Write( productName[0]);
Response.Write( unitsInStock[0]);
}
</script>

<ag******@gmail .com> wrote in message news:11******** **************@ z34g2000cwc.goo glegroups.com.. .

cast the value to the type
ProductName.Add ((string)dr.Get Value(0));

Also, you will want to follow the .NET framework coding rules. I was
rather confused at what you were doing. PascalCasing is for
Properties, MethodNames, and Types. You should make your variables
camelCased as...

List<string> productName = new List<string>();
List<double> unitsInStock = new List<double>();

this will help remove confusion in the future.

Here's a link for the guidelines...
http://msdn.microsoft.com/library/de...guidelines.asp

You will definately want to buy the book....
http://www.amazon.com/gp/product/032...lance&n=283155
the most important book you will ever buy for .NET or any development.

Let me know if you have other questions...

[agapeton]

Oops sorry...

unitsInStock.Ad d(Convert.ToDou ble(dr.GetValue (1)));

For the other one, these would also work...
productName.Add (Convert.ToStri ng(dr.GetValue( 0)));
productName.Add (dr.GetValue(0) .ToString( ));

[Web learner]

Aha.... The problem is solved and I learnt too.

Thanks a lot.......

<ag******@gmail .com> wrote in message
news:11******** **************@ u72g2000cwu.goo glegroups.com.. .

Oops sorry...

unitsInStock.Ad d(Convert.ToDou ble(dr.GetValue (1)));

For the other one, these would also work...
productName.Add (Convert.ToStri ng(dr.GetValue( 0)));
productName.Add (dr.GetValue(0) .ToString( ));

[Otis Mukinfus]

On Tue, 21 Mar 2006 16:37:14 -0600, "Web learner" <be******@learn ing.edu> wrote:

Thanks for your helps. I have modified the code and attach it at the bottom of this message.

At line unitsInStock.Ad d((double)dr.Ge tValue(1)); I still get same error: Specified cast is not valid

It seems to me, unitsInStock is NOT a double (as Jon Skeet has said). I suggest
that having a unit count column in a table declared as double would be a rare
occasion or error. Counting columns are generally declared as integers.

Why not look at the table design and see if the unitsInStock column really is a
double? The error message you are receiving is telling you it is not a double
but something else (probably an integer).

Otis Mukinfus
http://www.arltex.com
http://www.tomchilders.com

[Otis Mukinfus]

On Mon, 20 Mar 2006 18:32:52 -0600, "Web learner" <be******@learn ing.edu> wrote:

In the following code, I want ArrayList object x to be of type double.

How can I do that?

--Thanks

SqlConnection objConnection = new
SqlConnection( "server=(local) \\SQLEXPRESS; database=Northw ind; integrated
security=true; ");
String strSQL = "SELECT ProductName, UnitsInStock FROM Products
WHERE UnitsInStock >= 50";
SqlCommand objCommand = new SqlCommand(strS QL, objConnection);

objConnection.O pen();

ArrayList strLabel = new ArrayList();
ArrayList x = new ArrayList();

SqlDataReader dr = objCommand.Exec uteReader();

while (dr.Read())
{
object[] values1 = new object[0];
dr.GetValues(va lues1);
strLabel.Add(va lues1);

object[] values2 = new object[1];
dr.GetValues(va lues2);
x.Add(values2);
}

dr.Close();
objConnection.C lose();

In the NorthWind database the UnitsInStock column is a smallint. You must use
dr.GetInt16() to get this value.

Otis Mukinfus
http://www.arltex.com
http://www.tomchilders.com