Programming Primer Inheritance CS

Programming Primer Inheritance CS

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  A Programme Underthe compumitra Series Programming Primer - INHERITANCE LAB WORK GUIDE 1
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  OUTLINE Inheritance Using C#in asp.net A Parent-Child Class Example. Example Explanation. Home Exercise. Summary 2
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  Inheritance Using C# inasp.net 3
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  InheritanceCS -Web SiteCreation-1 From Start Page Click New Website and reach this screen 2. Select 'ASP.NET Empty Web Site' 3. Select Location=File System 4. Click 'Browse..' tab to select the location where you want to save your Web Site 5. click 'OK' 1. Select Language=Visual C#  By default Your Web Site shall be saved in the Location- "C:Documents and SettingsMy DocumentsVisual Studio 2008WebSites." Change it to  "C:Learner<student-id>ProgrammingPrimerInheritanceCS" folder4
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  InheritanceCS -Web SiteCreation-2 In the Solution Explorer Window Select the path -> Right click -> Add New Item… 5
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  InheritanceCS -Web SiteCreation-3 'Add New Item' dialog box will open 1. Select 'Web Form' 2. Simply Click on 'Add' button 6
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  InheritanceCS – Creatinga Button to create an event handler 2. Set the 'Text' Property equal to 'Inheritance' 1. Select and Drag and Drop 'Button' in div 7
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  InheritanceCS – CreatingOutput Display Placeholders Using Label 4. Set the 'Text' Property equal to 'Blank' 1. Press 'Enter' key to bring the cursor one line below. 2. Select and Drag and Drop Two 'Labels' in div Like 'Label1', Set the 'Text Property' of 'Label2'. 3. Select the 'label1' 8
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  InheritanceCS – CopyCode-1 Child c = new Child(); string n; n = c.C1(); Label1.Text = n; string m; m = c.P1(); Label2.Text = m; Copy this Code 9
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  InheritanceCS -Paste Code-1 Goto 'Default.aspx.cs' by double clicking on 'Button' ('Inheritance' Button) of 'Default.aspx' and 'Paste' the Code in 'Button1_Click' handler. Child c = new Child(); string n; n = c.C1(); Label1.Text = n; string m; m = c.P1(); Label2.Text = m; 10
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  InheritanceCS – CopyCode -2 public class Parent { string s; public string P1() { s = "Parent P1"; return s; } } public class Child : Parent { string r; public string C1() { r = "Child C1"; return r; } } Copy this Code 11
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  InheritanceCS - PasteCode-2 Run Code By pressing 'F5' 'Paste' code after the End of '_Default' class public class Parent { string s; public string P1() { s = "Parent P1"; return s; } } public class Child : Parent { string r; public string C1() { r = "Child C1"; return r; } } Child c = new Child(); string n; n = c.C1(); Label1.Text = n; string m; m = c.P1(); Label2.Text = m; 12
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  InheritanceCS -Output Click on 'Inheritance' button. Outputon browser Output after clicking 'Inheritance' button. Output from 'P1 Function' of 'Parent' class, although called using a child class object. Output from 'C1 Function' of 'Child' class 13
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  public partial class_Default : System.Web.UI.Page { protected void Button1_Click(object sender, EventArgs e) { Child c = new Child(); string n; n = c.C1(); Label1.Text = n; string m; m = c.P1(); Label2.Text = m; } } public class Parent { string m; public string P1() { m = "Parent P1" ; return m; } } public class Child : Parent { string r; public string C1() { r = "Child C1"; return r; } } InheritanceCS - Example Explanation -1 This is 'Child' class, which 'Inherits' 'Parent' class and has 'C1' function This is 'Parent' class, which has 'P1' function. This statement creates the object 'c' of 'Child' class. This statement uses the object 'c' of 'Child' class but using a method in 'parent' class. This is possible due to INHERITANCE. This statement uses the object 'c' of 'Child' class using a method in 'Child' class itself. This is normal usage. 14
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  public partial class_Default : System.Web.UI.Page { protected void Button1_Click(object sender, EventArgs e) { Child c = new Child(); string n; n = c.C1(); Label1.Text = n; string m; m = c.P1(); Label2.Text = m; } } public class Parent { string m; public string P1() { m = "Parent P1" ; return m; } } public class Child : Parent { string r; public string C1() { r = "Child C1"; return r; } } InheritanceCS- Example Explanation - 2 This is 'C1' function of 'Child' class. This statement 'returns' the value of 'r'. This statement calls the function 'C1' of 'Child' class and stores returned value in 'n' which is output in next line as "Child C1" This statement calls the function 'P1' of 'Child' class and stores returned value in 'm' which is output in next line as "Parent P1" This is 'P1' function of 'Parent' class. 15
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  InheritanceCS- Example Explanation- 3 'n=c.C1( )' statement calls the function 'C1' of 'Child' class. 'm=c.P1( )' statement calls the function 'P1' of 'Parent' class. This is actually done using a child class object. 16
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  InheritanceCS: Home Exercise Write a program similar to the example given which can demonstrate two classes "polygon" and a child class "square". From the main routine, Use class "polygon" to return the string "sides" and use class "square" to return the string "4". Finally display the string, "I am a polygon called square, I have 4 sides". Remember that the program should be based on INHERITANCE.  You can further extend this program where a user inputs the name of a polygon and based on user's provided name the program returns number of sides. For example input triangle to return "3 sides" and square to return "4 sides".  Modify any of these programs to test whether a parent class object can use methods or properties from child class. 17
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  InheritanceCS : LearningSummary Review Concept of Inheritance Child class inherits properties of parent class. Objects created from child class can always use methods and properties from parent class. (The reverse is not true). Programming techniques to create classes, and subclasses. Programming techniques to return values. Programming techniques to concatenate strings. 18
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  Ask and guideme at sunmitraeducation@gmail.com Share this information with as many people as possible. Keep visiting www.sunmitra.com for programme updates. 19