Hello,

I wrote a control derived from the ASP.NET DropDownList. I want to be able
to automatically databind the derived dropdown list and then
programmatically set the selected item through a property in this control. I
am not sure what the correct order of initialization should be. If I load
all the items in the OnLoad() method, then the property is executed first
and my list's selected index is 0. If I load everything in the OnInit()
method, then I don't know if it's a good programming practice to load the
items for every request instead of letting the control's viewstate handle
this. What's your recommendation? I am using VS.NET 1.1 and here's the code
I am using...

Thanks...

public class USStateDropDownList : DropDownList
{
 USStateWithDataDataSet stateDS;

 protected override void OnInit(EventArgs e)
 {
  base.OnInit( e );

  stateDS = GetData();

  Page.Response.Write( "1<br />" );
 }

 protected override void OnLoad(EventArgs e)
 {
  base.OnLoad( e );

  if( !Page.IsPostBack || !Page.EnableViewState )
  {
   LoadItems();
  }

  Page.Response.Write( "2<br />" );
 }

 /// <summary>
 /// Loads the drop-down list's items into the control.
 /// </summary>
 private void LoadItems()
 {
  DataValueField = stateDS.USState.StateCodeColumn.ColumnName;
  DataTextField = stateDS.USState.StateNameAndCountColumn.ColumnName;

  DataSource = stateDS.USState;
  DataBind();

  ListItem defaultItem = new ListItem( "- Choose a State -",
String.Empty );
  Items.Insert( 0, defaultItem );
  SelectedIndex = 0;
 }

 /// <summary>
 /// Gets the US State data from the database.
 /// </summary>
 private USStateWithDataDataSet GetData()
 {
  USStateWithDataDataSet stateDS = null;
  string cacheKey = "USStateWithData";

  if( null == Page.Cache[ cacheKey ] )
  {
   SubdivisionDataProvider subdivData = new SubdivisionDataProvider();

   // Obtain the data from the database
   stateDS = subdivData.GetRegionsWithData();

   // Add the state data to the cache.
   Page.Cache.Add(
    cacheKey,
    stateDS,
    null,
    Cache.NoAbsoluteExpiration,
    TimeSpan.FromHours( 3D ),
    CacheItemPriority.Normal, null );
  }
  else
  {
   // Retrieve the data from the cache.
   stateDS = (USStateWithDataDataSet)Page.Cache[ cacheKey ];
  }

  return stateDS;
 }

 /// <summary>
 /// Gets or sets the USPS 2-character code of the selected state.
 /// </summary>
 [Description("The selected state as a 2 character code.")]
 public string SelectedStateCode
 {
  get
  {
   return SelectedValue;
  }
  set
  {
   Page.Response.Write( "3<br />" );
   ListItem myItem = Items.FindByValue(value.ToUpper());
   SelectedIndex = -1;
   if( null != myItem )
   {
    myItem.Selected = true;
   }
  }
 }

 public USStateDropDownList()
 {
  stateDS = null;
 }
}