Session 08: Architecture Controllers or Managers Graphical User Interface (GUI) FEN 2013-04-141AK -...

Session 08: Architecture

Controllers or Managers

Graphical User Interface (GUI)

FEN 2013-04-14 1AK - IT Softwarekonstruktion

N-tier (multi-tier) Architecture

WebServer

Browser

Client

Internet

Dedicated Client

• Database access layer: All code to access database is here. Makes it possible to change data store.

• Web server accesses application layer – not the database directly.

• Easier maintenance:• No business logic in the web

server (or other clients).• Application server: All (almost)

business logic is re-used.• New client may be added without

code duplication.

DB

DatabaseServer

Application Server

Database Access Layer

Backend

Mobile

Client

Client accessing web services

FEN 2013-04-14 2AK - IT Softwarekonstruktion

New Dedicated Client

Controller Object

• So far we have had our business logic and “user interface” in the Main method

• This obviously not a good design!• Normally one will used what is

known as a layered ( or n tier) architecture, for instance:– UI– Controller– Model– Database

FEN 2013-04-14 AK - IT Softwarekonstruktion 3

Application

For now we focus on the application

layer

More Banking

View Code (Banking4)FEN 2013-04-14 AK - IT Softwarekonstruktion 4

Design

• This design is based on the fact that accounts normally are accessed from Customer. (Hence the complicated and inefficient implementation of GetAllOwners).


Exercises

• Exercises 1- 3 on Session08.docx.

• Extra : 4 – 6 on Session08.docx


Remember Banking4 ?

View Code (Banking4)FEN 2011-03-08 UCN T&B: IT Technology 7

Banking4 with GUI (Banking5)

View Code (Banking4GUI)FEN 2011-03-08 UCN T&B: IT Technology 8

How to Create a GUI for an Existing Project

• Firstly you must have a working project with model and controller, for instance Banking4.

• First step is to create a new solution in Visual Studio:

FEN 2011-03-08 UCN T&B: IT Technology 9

It must be a “Windows Form Application”

Give it a good name.

And choose a location for it.



New Form in VS

Toolbox. Here you find GUI components

Properties. Here you can edit components. For instance give the

form a good name


• Right click on the solution. Choose ‘Add’ and ‘Existing Project’.• Locate the project you want to add the GUI to:


Here is the project file for

‘Banking4’

Choose that.


• Now ‘Banking4’ shows in the Solution Explorer in Visual Studio:



• Next we want to make the project (‘Banking4’) known to our GUI project:

• You must use the namespace of Banking4:• Right click on the form and choose ‘View Code’• Type this using:


But the compiler doesn’t recognises

it?

Right click on ‘References’ for the GUI project in the Solution Explorer and choose ‘Add

Reference’



Choose the project tab.

Choose the project you want – Banking4

...and ‘OK’

Now the compiler recognises ‘Banking4’

namespace and we are ready.

Using the Existing Project

• Right click on the form, choose ‘View Code’, and now we can write code, for instance get an instance of the controller:

namespace Bank4WithGUI

{

public partial class Form1 : Form

{

private BankCtr myBank = BankCtr.GetInstance();

public Form1()

{

InitializeComponent();

}

}

}


Now myBank can be used in the form, and we are able to

communicate with the Banking4 application.

Adding Components and Controls to the Form• Drag- and-drop.


Label

ToolStrip

TextBox

Button

You may change the properties of components

Adding Code

• Test data is added by the constructor.

• New method added by me.


//---public Form1() //Constructor{ CreateTestData();//my method InitializeComponent();}

//---private void CreateTestData(){ Customer c = new Customer(1, "Peter Thomsen"); myBank.AddCustomer(c); myBank.AddCustomer(new Customer(2, "Ib Helmer")); BankAccount acc1 = new BankAccount(1, 8, 100); BankAccount acc2 = new BankAccount(2, 0.25, 0); BankAccount acc3 = new BankAccount(3, 5, 1000); c = myBank.GetCustomer(1); c.AddAccount(acc1); c.AddAccount(acc2); c.AddAccount(acc3); c = myBank.GetCustomer(2); c.AddAccount(acc2);}

Getting some Action

• Double click on the Find Customer Button and you get an empty event handler method for the button. This method is executed when the button is clicked.

• Type in the code for the actions that you want.


//--- private void button1_Click(object sender, EventArgs e) {

}

private void button1_Click(object sender, EventArgs e) { string input = this.textBox1.Text; int custNo = Convert.ToInt32(input); //no error handling Customer c = myBank.GetCustomer(custNo); this.textBox2.Text = c.Name; }

Getting some Action

• Components are objects and may used like any other objects.



• Use ‘this’ and the IntelliSense to find variable names of components and properties of components.

Error Handling - Exceptions

• If, what is entered here, not is a valid and existing customer number; some exception (NumberFormat or NullPointer) will make the program crash.



Error Handling - Exceptions

• We want to catch and handle that exception.

• That is done by enclosing the code in a try-block.

• After that we have a catch-block where we handle the exception.


private void button1_Click(object sender, EventArgs e){ string inString = textBox1.Text; try { int custNo = Convert.ToInt32(inString); c = bankCtr.GetCustomer(custNo); textBox2.Text = c.Name; } catch (Exception excep) { MessageBox.Show("Customer number must be an integer"); }}

Investigate Banking4GUI

Exercises

• Exercises 7 on Session08.docx.

• Extra : 8 on Session08.docx


Session 08: Architecture Controllers or Managers Graphical User Interface (GUI) FEN 2013-04-141AK -...

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Transcript of Session 08: Architecture Controllers or Managers Graphical User Interface (GUI) FEN 2013-04-141AK -...