Real Time Example of Reflection in ASP.net

While preparing for the interview, prior to joining my current employer, I came across the term Reflection. Questions on Reflection had been asked many a times. It was high time to learn the concept of Reflection. In turn it helped me to solve my first assignment with current employer, Trigyn Technlogies Limited. I was able to solve the problem only because I knew that there is something called reflection which could help me to solve such kind of problems.

Now here was the requirement

• Needed to have a user control for Grid View
  
• To Bind data to above grid view, two parameters were require – Year, Department
  

WebUserControl1.ascx

 

<%@
Control
Language="C#"
AutoEventWireup="true"
CodeBehind="WebUserControl1.ascx.cs"
Inherits="ReflectionSample.WebUserControl1"
%>

<asp:GridView
ID="GridView1"
runat="server">

</asp:GrifView>

 

WebUserControl1.ascx.cs

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

 

namespace ReflectionSample

{

public
partial
class
WebUserControl1 : System.Web.UI.UserControl

{

protected
void Page_Load(object sender, EventArgs e)

{

        GridView1.DataSource = GetData(2008, "Support");

}

 

private
DataSet GetData(int year, string department)

{

throw
new
NotImplementedException();

}

}

}

 

Default.aspx

 

<div
id="placeUserControl"
runat="server">

</div>

 

 

Challenges

• User Control to be loaded dynamically into the .aspx page.
  
• Year, Department parameters' value were coming from the .aspx page (outside the user control). Into the above code snippet its hard coded.
  

Solution

1. Added two properties for Year and Department into User control's code behind file.
   
2. The above properties' value had been used for GetData method. User control's code behind file would look like below.
   

   
    

WebUserControl1.ascx.cs

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

 

namespace ReflectionSample

{

public
partial
class
WebUserControl1 : System.Web.UI.UserControl

{

public
int Year { get; set; }

public
string Department { get; set; }

 

protected
void Page_Load(object sender, EventArgs e)

{

GridView1.DataSource = GetData(Year, Department);

}

 

private
DataSet GetData(int year, string department)

{

throw
new
NotImplementedException();

}

}

}

1. Loaded user control (run time) into .aspx page.
   
2. Code behind file of .aspx page would look like below
   

   
    

Default.aspx.cs

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Reflection;

 

namespace ReflectionSample

{

public
partial
class
_Default : System.Web.UI.Page

{

protected
void Page_Load(object sender, EventArgs e)

{

int Year = 2008;

string Department = "Support";

 

UserControl userControl = Page.LoadControl("WebUserControl1.ascx") as
UserControl;

Type userControlType = userControl.GetType();

 

PropertyInfo propertyYear = userControlType.GetProperty("Year");

 

PropertyInfo propertyDepartment = userControlType.GetProperty("Department");

 

propertyYear.SetValue(userControl, Year, null);

propertyDepartment.SetValue(userControl, Department, null);

 

placeUserControl.Controls.Clear();

placeUserControl.Controls.Add(userControl);

 

}

}

}

 

Your comments, suggestions, alternate solutions are welcome J