Easy Example for Model View Presenter in ASP.NET - C#

Model View Presenter

Model View Presenter is a software approach pattern conceived as derivative of Model View Controller.

What is Model?

Model is a domain level or business level object. A model accomodates application data and provides behaviours to systematically access it. It should be independent, it should not have any association with user interface issues. So we can reuse the same model for different type of UI level applications.

What is View?

A View is a windowpane for showing the model data or elements to the application users. Model does not have direct link to the views. View know about thier Models, but not the other way around.

What is Presenter?

Presenter will address the user input and use this to manipulate the model data. View will pass the user input actions to the Presenter for interpretation. Presenter will act on the received data from View and communicate with Model and produce results to the View.

Here is the classic example for implementing and understanding Model View Presenter pattern in an ASP.Net application. I believed this will helps you to get a good start in Model View Presenter.

Step 1: Create an interface for a business object (Model). For example:

public interface ICircleModel
{
    double getArea(double radius);
}

Step 2: Create a class for Model

public class CModel: ICircleModel
{
    public CModel(){}
    
    public double getArea(double radius)
    {
        return Math.PI * radius * radius;
    }
}

Step 3: Create an interface for View

public interface IView
{
    string RadiusText { get; set;}
    string ResultText { get; set;}
}

Step 4: Create UI like below with a Label, TextBox and Button. Textbox for getting radius of the circle, Label is for displaying the area and Button is for calculating the Area

<html xmlns="<a href="%22http://www.w3.org/1999/xhtml%22">http://www.w3.org/1999/xhtml</a>">
<head runat="server">
<title>MVP-Easy Example for ASP.Net C#</title>
</head>
<body>
<form id="form1" runat="server">
<table>
<tr>
<th colspan="2">Calculate Area of Circle</th>
</tr>
<tr>
<td>Enter Radius</td>
<td><asp:TextBox ID="TextRadius" runat="server"></asp:TextBox></td>
</tr>
<tr>
<td>Result:</td>
<td><asp:Label ID="LabelResult" runat="server" ForeColor="red"></asp:Label></td>
</tr>
<tr align="right">
<td colspan="2"><asp:Button ID="ButtonResult" runat="server" Text="Get Area?" OnClick="ButtonResult_Click" /></td>
</tr>
</table>
</form>
</body>
</html>

Step 5: Create a Presenter class for collecting user inputs from View and pass view details to the Model.

public class CPresenter
{
    IView mview;
    public CPresenter(IView view)
    {
        mview = view;
    }
    public double CalculateCircleArea()
    {
        CModel model = new CModel();
        mview.ResultText = model.getArea(double.Parse(mview.RadiusText)).ToString();
        return mview.ResultText.ToString();
    }
}

Step 6: Code-behind of ASPX page - View is communicating to the Model via Presenter

public partial class _Default : System.Web.UI.Page,IView 
{
    protected void Page_Load(object sender, EventArgs e)
    {
    }
    protected void ButtonResult_Click(object sender, EventArgs e)
    {
        CPresenter presenter = new CPresenter(this);
        presenter.CalculateCircleArea();
    }
    public string RadiusText
    {
        get{return TextRadius.Text;}
        set{TextRadius.Text = value;}
    }
    public string ResultText
    {
        get { return LabelResult.Text; }
        set { LabelResult.Text = value; }
    }
}

Now, I am sure, you are also feeling the same, it is pretty simple :)

Happy MVP Coding!!!

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

RB Changanacherry

Team Leader

India

Member

I am Rajesh Babu, currently working for Nous Infosystems, Bangalore. I have 6 plus years experience in Microsoft Technologies.

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It is a simple example for the implemention of Model View Presenter in Asp.Net

Type	Article
Licence	CPOL
First Posted	22 Jan 2009
Views	53,254
Bookmarked	31 times

C#Windows
Intermediate