add control folder, add cousescontrol.ascx
add drop down list to cousescontrol.ascx
change auto post back to true in property window
//course control.ascx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using Ctti.Data;
namespace CttiDemo.Controls
{
public partial class CoursesControl : System.Web.UI.UserControl
{
//Step 3: define the public event
public event CourseSelectionDelegate CourseSelect;
private CTTIEntities1 DB = new CTTIEntities1();
//Property returns the selected value of the DDL as an int instead of string
public int SelectedId
{
get
{
return int.Parse(uxCourses.SelectedValue);
}
}
protected void Page_Load(object sender, EventArgs e)
{
//populate the DDL
if (!IsPostBack)
{
uxCourses.DataSource = DB.Courses.Select(c => new { Id = c.Id,
Name = c.CourseName }).ToList();
uxCourses.DataTextField = "Name";
uxCourses.DataValueField = "Id";
uxCourses.DataBind();
//raise the event first time page loads so event handler can load form
uxCourses_SelectionChanged(this, null);
}
}
protected void uxCourses_SelectionChanged(object sender, EventArgs args)
{
//Step 4: raise the event
//if event is not raised, raise event
if(CourseSelect != null)
{
//we need to get the course from the data layer using the id value from DDL
int id = int.Parse(uxCourses.SelectedValue);
Course crs = DB.Courses.Find(id);
var c = new CourseEventArgs
{
Id = crs.Id,
CourseCode = crs.CourseCode,
CourseName = crs.CourseName,
Description = crs.Description,
Duration = crs.Duration,
Fee = crs.Fee
};
//fire event everywhere
CourseSelect.Invoke(this, c);
}
}
}
//Step 1: define a custom event args class
public class CourseEventArgs : EventArgs
{
public int Id { get; set; }
public string CourseCode { get; set; }
public string CourseName { get; set; }
public decimal Fee { get; set; }
public int Duration { get; set; }
public string Description { get; set; }
}
//Step 2: define a delegate
public delegate void CourseSelectionDelegate(object sender, CourseEventArgs args);
}
------------------------------------------------------------------
drag coursecontrol onto courses.aspx webform
//course.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace CttiDemo
{
public partial class Courses : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//drop down list from coursecontrol.ascx fires event, courses.asp receives event
uxCourses.CourseSelect += UxCourses_CourseSelect;
}
//event handler
private void UxCourses_CourseSelect(object sender, Controls.CourseEventArgs args)
{
uxName.Text = args.CourseName;
uxCode.Text = args.CourseCode;
uxFee.Text = args.Fee.ToString("c");
uxDuration.Text = args.Duration.ToString() + " hrs";
uxDescription.Text = args.Description;
}
}
}
