An aspx page is always recreated from scratch so your dsRoles variable is not going to survive. Either:
(a) Recreate it each time
(b) Save it as a session variable
(c) Save it as a global variable

BTW I seem to recognize this:

dsRoles = DataLayer.ExecuteQuery("as_GetRole", Params, CommandType.StoredProcedure);

What was causing the error you were having ?


>As I'm VERY new to ASP.Net, I'm not sure I understand how things work.
>
>I put together a composite usercontrol. It has a listbox that shows user roles. When a role is selected, the RoleName, RoleCode, and
>Description are pulled from data and displayed in 3 textboxes - at leats that's what the goal is.
>
>At this point when I run it the listbox is populated. But the DataSet that's bound to the list is then null when I attempt to access
>it from SelectedIndexChanged. I'm guessing that I'm doing this wrong.
>
>Here's the code.
>
>

>using System;
>using System.Collections.Generic;
>using System.Configuration;
>using System.Data;
>using System.Data.Common;
>using System.Data.SqlClient;
>using Marois.Common.DataAccess;
>
>public partial class crlRoles : System.Web.UI.UserControl
>{
>    private DataSet dsRoles = null;
>    private DataAccess DataLayer = null;
>
>    protected void Page_Load(object sender, EventArgs e)
>    {
>        if (!IsPostBack)
>        {
>            DataLayer = new DataAccess();
>            _LoadList();
>        }
>    }
>
>    private void _LoadList()
>    {
>        DataLayer.ProviderInvariantName = "System.Data.SqlClient";
>        DataLayer.ConnectionString = ConfigurationManager.ConnectionStrings["ApexGlobalConnectionString"].ConnectionString;
>
>        dsRoles = DataLayer.ExecuteQuery("as_GetRole", CommandType.StoredProcedure);
>
>        lstRoles.DataSource = dsRoles.Tables[0];
>        lstRoles.DataTextField = "RoleName";
>        lstRoles.DataBind();
>    }
>
>    protected void lstRoles_SelectedIndexChanged(object sender, EventArgs e)
>    {
>        if (lstRoles.SelectedIndex > -1)
>        {
>            int RoleKey = (int)dsRoles.Tables[0].Rows[lstRoles.SelectedIndex]["RoleKey"];
>
>            SqlParameter pRoleKey = new SqlParameter("@RoleKey", RoleKey);
>            List<DbParameter> Params = new List<DbParameter>();
>            Params.Add(pRoleKey);
>
>            dsRoles = DataLayer.ExecuteQuery("as_GetRole", Params, CommandType.StoredProcedure);
>
>            txtRoleName.Text = dsRoles.Tables[0].Rows[0]["Name"].ToString();
>            txtRoleCode.Text = dsRoles.Tables[0].Rows[0]["RoleCode"].ToString();
>            txtDescription.Text = dsRoles.Tables[0].Rows[0]["Description"].ToString();
>        }
>    }
>}
>
>