PatternMVCpdf

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<b>Introduction to</b>

<b>MVC Design pattern</b>

陳偉凱

台北科技大學資工系

<b>2</b>

<b>MVC: Model View Controller</b>

z

<b>Splits user interface </b>

<b>interaction into</b>

<b>three </b>

<b>distinct roles</b>

<b>.</b>

„ <b>The </b><i><b>model</b></i><b>represents some </b>

<b>information about the </b>
<b>domain. </b>

„ <b>The</b><i><b>view</b></i><b>represents the </b>

<b>display of the model in the </b>
<b>UI. </b>

„ <b>The</b><i><b>controller</b></i><b>takes user </b>

<b>input, manipulates the </b>
<b>model, and causes the view </b>

<b>to update appropriately.</b>

a
b

c

a b c

a = 50%
b = 30%
c = 20%

<b>change notification</b>
<b>requests, modifications</b>
x

y
z

a b c

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<b>3</b>

<b>MVC: How it Work</b>

z

<b>Separating the </b>

<b>presentation</b>

<b>from the </b>

<b>model</b>

„<b>Fundamentally presentation and model are about </b>

<b>different concerns.</b>

„<b>Depending on context, users want toseethe same basic </b>

<b>model information in differentways.</b>

„<b>Non-visual objects are usually easier to testthan visual </b>

<b>ones.</b>

„<b>Thepresentation dependson themodel</b>
„<b>Observerpattern [GOF]</b>

Model
Presentation

<b>MVC: How it Work</b>

z

<b>Separating the </b>

<b>controller</b>

<b>from the </b>

<b>view</b>

„<b>Support editable and non-editable behavior: one view + </b>

<b>two controllers</b>

„<b>Controller = Strategiespattern [GOF]</b>
„<b>Useful for Web interface</b>

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<b>5</b>

<b>MVC: When to Use It</b>

z

<b>The value of MVC lies in its two </b>

<b>separations</b>

„<b>Separating the presentation from the model</b>

„<b>Separating the controller from the view (less important)</b>

z

<b>Don’t use it in very simple systems where the </b>

<b>model has no real behavior in it anyway.</b>

<b>6</b>

<b>Example code #1</b>

<b>namespace XXX</b>

<b>{</b>

<b>class Program</b>

<b>{</b>

<b>static model m = new model();</b>

<b>static Form1 f = new Form1(m);</b>

<b>static void Main(string[] args)</b>

<b>{</b>

<b>Application.Run(f);</b>

<b>}</b>

<b>}</b>

<b>}</b>

model

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<b>7</b>

<b>Example code #1</b>

<b>namespace XXX</b>
<b>{</b>

<b>class Form1 : Form</b>
<b>{</b>

<b>private model m;</b>

<b>public Form1(model m)</b>
<b>{</b>

<b>this.m = m;</b>
<b>…</b>

<b>}</b>

<b>private void B1_Click(object …)</b>
<b>{</b>

<b>m.press(1);</b>

<b>xxx.Text = m.GetResult().ToString();</b>
<b>}</b>

<b>}</b>

<b>}</b>

model
form

<b>Example code #2</b>

<b>namespace XXX</b>

<b>{</b>

<b>class Program</b>

<b>{</b>

<b>static Form1 f = new Form1();</b>

<b>static void Main(string[] args)</b>

<b>{</b>

<b>Application.Run(f);</b>

<b>}</b>

<b>}</b>

<b>}</b>

_model

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<b>9</b>

<b>Example code #2</b>

<b>namespace XXX</b>
<b>{</b>

<b>class Form1 : Form</b>
<b>{</b>

<b>private model m = new model;</b>
<b>public Form1()</b>

<b>{</b>
<b>}</b>

<b>private void B1_Click(object …)</b>
<b>{</b>

<b>m.press(1);</b>

<b>xxx.Text = m.GetResult().ToString();</b>
<b>}</b>

<b>…</b>
<b>}</b>
<b>}</b>

model
form

<b>10</b>

<b>Example Class Diagram #1</b>

List<Word>

<b>SpellerForm</b>

-words

<b>Dictionary</b>

-English
-Chinese

<b>Word</b>

View & Control Model

-Question
-Solution

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<b>11</b>

<b>Example Class Diagram #2</b>

<b>SpellerForm</b>

-words

<b>Dictionary</b>

-English
-Chinese

<b>Word</b>

+Start()

+Next()
+GetQuestion()
+IsCorrect()
+GetScore()

<b>Speller</b>

Model Facade
View & Control

-Question
-Answer

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