The Start Menu……..ExposedWhat you never knew existed

Model View Presenter in

ASP.NET 2.0

Introductions• Nick Parker

• Tim Gifford

Gifford Consulting• Embedded Agile Coaching

– Adaptive, Informed Planning– Simple Design– Refactoring– Test-Driven Development– Continuous Integration– Self-Managing Teams– Approaching Deadline Behaviors

Nick Parker• Two Rivers Marketing

• Microsoft Visual C# MVP

Agenda• Compare Code-Behind vs. MVP• Demo 1• MVP Definition• Comparison to Model View Controller • Demo 2• Advantages• Agile Testing Overview• Disadvantages• Review/Resources/Q&A

Expectations?

Code-Behind vs MVP (Code)protected void btnAdd_Click(object sender, EventArgs e) { txtFirstName.Enabled = true; txtLastName.Enabled = true; txtEmailAddress.Enabled = true; btnSave.Enabled = true; btnSave.Visible = true; btnAdd.Enabled = false; btnAdd.Visible = false; btnCancel.Enabled = true; btnCancel.Visible = true; txtContactId.Value = string.Empty; btnUpdate.Enabled = false; btnUpdate.Visible = false; }

private void EditContact(Guid guidContactId) { //Get the contact factory = config.BuildSessionFactory(); ContactDTO contact = null; ISession session = factory.OpenSession(); contact = (ContactDTO)session.CreateCriteria( typeof(ContactDTO)).Add(Expression.Eq("ContactId", guidContactId)).UniqueResult(); session.Close(); if (contact != null) { txtFirstName.Text = contact.FirstName; txtLastName.Text = contact.LastName; this.txtEmailAddress.Text = contact.EmailAddress; this.txtFirstName.Enabled = true; txtLastName.Enabled = true; txtEmailAddress.Enabled = true; btnSave.Enabled = false; btnSave.Visible = false; btnCancel.Enabled = true; btnCancel.Visible = true; btnAdd.Enabled = false; btnAdd.Visible = false; txtContactId.Value = guidContactId.ToString(); btnUpdate.Enabled = true; btnUpdate.Visible = true; } }

protected void btnSave_Click(object sender, EventArgs e) { presenter.SaveContact(); }

protected void btnUpdate_Click(object sender, EventArgs e) { presenter.UpdateContact(); }

protected void btnAdd_Click(object sender, EventArgs e) { presenter.NewContact(); }

protected void btnCancel_Click(object sender, EventArgs e) { presenter.Cancel(); }

public IList<ContactDTO> DataSource { set { this.gvContacts.DataSource = value; this.gvContacts.DataBind(); } }

public ITextBoxAdapter EditFirstName { get { return new TextboxAdapter(this.txtFirstName); } }

public ITextBoxAdapter EditLastName { get { return new TextboxAdapter(this.txtLastName); } }

public ITextBoxAdapter EditEmail { get { return new TextboxAdapter(this.txtEmailAddress); } }

Code-Behind vs MVP

Data Access

Business LogicDomain Model

Presentation

User Interface

Database

Data Access

Business LogicDomain Model

Code Behind

User Interface

Database

DemoSwap Demo

Model – View – Presenter

Model

Presenter

Update View

User Actions

Model• Responsibilities:

– Stores Data

• Collaborators:– None

• Anti-Collaborators:– Model does NOT talk to

the view– * Model’s don’t talk to me

either!

ViewResponsibilities:

Display and User Interface

Delegate User Actions to Presenter

Collaborators:

Presenter

Anti-Collaborators:Services

PresenterResponsibilities:

Map between the UI and the Data

Handle User Events

Collaborators:View

Model

Service

Anti-Collaborators:None*

Split Pattern• Passive View

– All synchronization between the View & Model is handled by the presenter

– Minimal behavior on the View

• Supervising Controller/Presenter– Allows for more advanced Data Binding– More behaviors handled by view

MVP vs MVC

•MVP is MVC done “right”

Data Access

Model

Presenter

View

Data Access

Model

Controller

View

MVP MVC

MVP UML(ish) Diagram

Advantages• Reduce duplicate code

• Reduce maintenance

• Separation of Concerns

• Testable/Test-Driven

• Reduce UI defects

Agile Testing

Unit Tests

Integration

UISelenium

Mercury Automated QA

FIT FitNesse

Nunit

Testing Layers

Unit Int UI

Brittleness Execution Time

DemoDisable/Hide Controls

Disadvantages• Complexity

• Learning Curve

When NOT to use MVP?

• Quick & Dirty

• Short Application Lifetime

• Support Staff

• Not supported in technology (VB 6.0)

ReviewBenefit

– Use MVP to create a unit tested UI– Helps minimize (or eliminate) defects

Costs– Complexity

Resources

Tim GiffordEmail: tim@giffordconsulting.com

Blog: blogs.giffordconsulting.com

Nick ParkerEmail: nickp@developernotes.com

Blog: http://developernotes.com

Code:http://code.google.com/p/developernotes/