Let us suppose you had a simple class of tags that you wanted to bind to an ASP.NET DropDownList control.

public class TagDetails
{
   private int tagID;
   public int TagID
   {
       get { return tagID; }
   }

   private string tagName;
   public string TagName
   {
       get { return tagName; }
       set { tagName = value; }
   }
   public TagDetails(int tagID, string tagName)
   {
       this.tagID = tagID;
       this.tagName = tagName;
   }
}

The DropDownList control on the .ASPX page looked like this.

<asp:DropDownList ID="ddlTagList" runat="server"/>

And for this class you had a method to return all tags called GetTags. How would you bind it to an ASP.NET DropDownList control? As such.

List<TagDetails> tags = new List<TagDetails>();
tags = tagDB.GetTags();
ddlTagList.DataSource = tags;
ddlTagList.DataTextField = "TagName";
ddlTagList.DataValueField = "TagID";
ddlTagList.DataBind();

At this point you may wish to add a blank item or select item row at the top of the DropDownList. That code can be found at Add Item to DropDownList After DataBind.

Labels: ASP.NET, DropDownList, Generic-List

We often want the first option in a drop-down list to not default to the first item in the list. Instead we would prefer the option of adding a --Select Item-- at the top of the asp:DropDownList. After the DataBind, execute an Item.Insert.

ddlAuthor.DataTextField = "FullName";
ddlAuthor.DataValueField = "AuthorID";
ddlAuthor.DataSource = authorDB.GetAuthors();
ddlAuthor.DataBind();
ddlAuthor.Items.Insert(0, "-- Select Author --");

Labels: ASP.NET, DropDownList