BSc (Hons) Software Engineering BSc (Hons) Computer ...Write VB.Net codes to implement the interface which displays a message box when the user clicks on the ‘Build Pizza’ button

of 21 Visual Programming (PROG21043C) SITE/DA 2012-2013 S2

BSc (Hons) Software Engineering

BSc (Hons) Computer Science with Network

Security & BSc.(Hons) Business Information

Systems

Cohort: BSE/11/FT, BCNS/11/FT, BIS11/FT

Examinations for 2012 – 2013 / Semester 2

MODULE : Visual Programming MODULE CODE: PROG 2104C Duration : 2 Hours & 30 Minutes Reading Time : 10 Minutes

Instructions to Candidates: 1. This question paper consists of three sections: Section A, Section B and

Section C.

2. Section A is compulsory.

3. Answer two questions from Section B or two questions for Section C.

4. Questions from section B should be answered using VB.Net only and

questions from section C should be answered using C#.Net only.

5. Total marks 100.

This question paper contains 7 questions and 21 pages.


SECTION A (Compulsory)

QUESTION 1: (40 MARKS)

a) The Norman’s design guideline applied to user interface design of computer

applications consist of six principles.

i. With the help of examples, and using diagrams where necessary,

describe the six normal design principles

(12 marks)

ii. The two figures below represents specific screen from windows

applications and have bad user interface design. Identify and describe

the main user interface problem(s), and also propose a solution for

each.

(4 marks)

Figure 1(a): An Error Message in a Message Box

Figure 1(b): A Form that captures banking details


b) Windows applications usually provide menus containing commands and

options, giving the user the ability to perform various tasks related to the

application. Consider the following menu, and answer the questions which

follow.

Figure 1(c): File Menu

i. Explain how you can use the menu strip control to create the menu in

figure 1(c) above.

(3 marks)

ii. How are you going the assign the shortcut property to each strip item?

(2 marks)

iii. Explain how you will assign a click event on the Exit menu strip item.

(2 marks)

c) The .NET Framework is a managed, type-safe environment for application

development and execution. It manages all aspects of program execution and

consists of two main components: the Common Language Runtime (CLR)

and the Base Class library (BCL). Briefly describe each component.

(4 marks)

d) The namespaces in the .NET base class library are organized hierarchically.

i. What is the root namespace of the .NET Framework?

(1 mark)


ii. What is the purpose of the namespace concept in the .NET

Framework?

(2 marks)

e) ADO.NET is the primary data access API for the .NET framework. It provides

classes necessary to develop database applications based on the

disconnected data access model.

i. Explain the disconnected data access model with reference to the two

main problems linked with the connected access model.

(2 marks)

ii. With the help of a diagram, explain the role of the DataSet and the

Data Provider components in the ADO.NET architecture.

(5 marks)

iii. Describe the command object with the help of an example.

(3 marks)


SECTION B

(Answer any two questions using VB.NET)


a) A bank has 4 types of accounts with annual interests rates as follows:

1. Savings 8%

2. Savings with cheque book 5%

3. Current 4%

4. Fixed deposits 10%

Write a VB.net program that allows the input of the current balance in textbox,

txtBalance and input type of account in textbox, txtAccount and displays the total

interest obtainable in label lblOutput, when the button, btnCalculate is clicked.

You have to make use of the Select statement. Ensure that the following

validations occur:

(Total 10 marks for part (a))

I. The textboxes should not be left empty.

II. Balance should be numeric and positive.

III. Account type should be in the appropriate range.

Provide appropriate error messages if the above conditions are not met.


Fig 2 a) (i)

Fig 2 a) (ii)


Fig 2 a) (iii)

Fig 2 a) (iv)

b) The Screenshot below shows part of a Pizza Order application


Fig 2 b)

Write VB.Net codes to implement the interface which displays a message box

when the user clicks on the ‘Build Pizza’ button.

(10 marks)

b) You are provided with the following screenshot of a media player application with

a progress bar control at the bottom. When the Start button is clicked the

Progress bar starts, the Play button of the player becomes visible.

(i) What is the purpose of this control? What are three important parameters of

the Progress Bar control? (4 marks)

(ii) Explain fully with the necessary VB.Net codes how you would implement

this progress bar when the Start Button is clicked. (6 marks)


Fig 2 c) (i)

Fig 2 c) (ii)

Fig 2 c) (iii)

(3 marks)


Question 3 (30 Marks)

Below are three screenshots of a small application to display the details of a

collection of songs. It consists of the Title, artist, format, duration (in minutes and

seconds), year it was released, and the category. All the details are stored in a

database named ‘Music_Collection’. The application consists of three forms,

containing the following controls: buttons, labels, list box and text boxes.

Depending on the choice of the user (Fig 3.1), it can either retrieve all the records

from the database and display all of them at one go in a data grid (Fig 3.1) or

display the record one by one (Fig 3.3).

The form named ‘Form3’ contains a datagrid to display data from a table name

Songs in the database mentioned above.The data is loaded only when the ‘Load

data’ button is pressed. The data in the database can be updated via the ‘Update

DB’ button (Fig 3.2)

Fig 3.1


Fig 3.2

Fig 3.3

You are required to write VB.NET codes for the following functionalities:

a) To declare class level variables to connect to the database

(3 marks)

b) To show all records in the datagrid at one go by clicking the ‘Load data’ button

– (8 marks)

c) To display the record one by one in a form called MusicList (Fig 3.3)

(8 marks)


d) To update the underlying database via the datagrid by clicking the ‘Update

DB’ button. The code should display a message indicating the number of

records changed in the database. (9 marks)

e) To close the application by clicking the ‘Exit’ button

(2 marks)

Question 4 (30 Marks)

Below are six screenshots of a small application to display the details of a collection

of songs. It consists of the Title, artist, format, duration (in minutes and seconds),

year it was released, category and a path to an image file representing the picture of

the artist. All the details are stored in plain text file: MusicCollection_tab_image.txt

(Fig 4.1). The application consists of three forms, containing the following controls:

buttons, labels, list box and text boxes. Depending on the choice of the user (Fig

4.2), it can either retrieve all the records from the text file and display all of them at

one go in a list box (Fig 4.3) or display the record one by one along with the picture

which it extracts from the path name(Fig 4.5).

Write VB.Net codes for the following:

(i) Appropriate global variables (3 marks)

(ii) Opening an appropriate stream reader to the text file (2 marks)

(iii) To read line by line till the end of the text file (2 mark)

(iv) Break each individual line into corresponding words (fields of the records)

(2 mark)

(v) For a clear button to clear all fields (2 marks)

(vi) For closing the stream reader (1 mark)

(vii) For the Exit button (1 mark)

(viii) For a sub procedure called ‘DisplayRecord()’ which will display one record at

a time like in Fig 4.5 below. (13 marks)

(ix) For the Last Button (4 marks)


Fig 4.1

Fig 4.2

Fig 4.3


Fig 4.4

Fig 4.5

Fig 4.6


SECTION C

(Answer any two questions using C#.NET)


You have been given the form below (Figure 5), with part of the implementation

details. The application demonstrates how to use C# arithmetic operators on integer

values and also shown in figure 5 are the names of the controls specified between

brackets, except for the radio buttons which are described below.

Figure 5: Maths Operator Form Design

RadioButtons description:

A groupbox control is used to group 5 different radio buttons, with the following

names: addition, subtraction, multiplication, division and remainder.

If the addition radio button is checked, and the user clicks on calculate button, the

value of the left operand is added to that to the right operand. In all cases, the left

operator is either added to (+), or subtracted from (-), or multiplied to (*), or divided -

normal division (/) or remainder/modular division (%) - by the right operator. The

result of the expression is displayed in the result textbox, and the expression in the

expression textbox.


Consider the code fragment below, which shows the implementation of calculate

button click event:

1. private void calculate_Click(object sender, System.EventArgs e) 2. { 3. int leftHandSide = Int32.Parse(leftHandSideOperand.Text); 4. int rightHandSide = Int32.Parse(rightHandSideOperand.Text); 5. int answer = doCalculation(leftHandSide, rightHandSide); 6. result.Text = answer.ToString(); 7. }

Code Listing 1: Implementation of calculate_Click

a) Explain the codes at line 3 and 4 in code listing 1 above.

(2 marks)

b) Write complete C# code for the implementation of the ‘doCalculation’ method

shown in the code listing 1 above. (Provide an implementation for all the

arithmetic operators on the form, as well as the display of the expression in

the expression textbox.)

(12 marks)

c) Briefly explain what each segment of a Try...Catch...Finally

(try...catch...finally) block does.

(3 marks)

d) If you catch IndexOutOfRangeException and Exception in two different

handlers, which one will run first, or will both be executed?

(3 marks)

e) There are several possible error conditions that can occur in the code

described in listing 1 above. Describe two possible error conditions, and write

try-catch blocks to handle each.

(2 x 5 marks)



a) In the context of database access in C#.NET, explain the following methods:

i. The Open() method

ii. The Close() method (2 marks)

b) Consider the form below ‘Student Application’ in figure 6 below, which accesses

two tables, namely, Application and Courses, from an MS SQL Server database,

named university.mdb. The table Application consists of the following fields:

student_id (int, auto-increment, not null), firstname (text, null), lastname(text,

null), phone(text, null), address(text, null), dob (text, null), course_A(text, null),

course_B(text, null), course_C(text, null). The table Courses consists of the

following fields: course_id(int, auto-increment, not null), course_name(text, null)

and course description(text, null). Answer the questions which follow. Clearly

mark any assumptions that you make where necessary.

Figure 6: Student Application Form

Button:

btn_select

Button:

btn_returnOne Button:

btn_returnAll

ListBox:

lb_selected

ListBox:

lb_available


i. Write the code to load all course names in the listbox ‘lb_available’,

when the form loads. Use the sql authentication with username set to

‘myUni’ and password ‘myUni25’ from the database server named

‘DBServer’. Use an appropriate try-catch statement for in your code.

(8 marks)

ii. Write the code for the following button click events, which allow the

applicant to select only three courses from listbox lb_available and add

them to lb_selected.

(10 marks)

private void btn_Select_Click(object sender, EventArgs e) {

…

}

private void btn_ReturnOne_Click(object sender, EventArgs e) {

…

}

private void btn_ReturnAll_Click(object sender, EventArgs e) {

… }

iii. Write the code to save the application made, in the table application,

when the button save is clicked. Note that the selected course names

are stored in fields: course_A, course_B, course_C. Use an

appropriate try-catch statement for in your code.

(10 marks)



a) In the context of a file access in C#.NET, explain the following components:

i. openFileDialog dialog.

ii. StreamReader Class.

(4 marks)

b) Consider the form, figure 7, ‘Add Student Marks’ below, with annotations for

all main controls. It records basic student personal details and their marks

obtained in the module Visual Programming. The lecturer inserts the student’s

personal details, together with a photo of the student and the marks obtained

in the module. The total mark for the module is computed from two

assignments of 50 marks each, which accounts for 40% of the total module

and the examination has a total of 100 marks and accounts for 60%. Answer

the questions which follow and clearly mark any assumptions that you make.

Figure 7: Add Student Marks form


i. Complete the code below, which loads the batches (BSE/11/FT,

BCNS/10B/FT, BCNS/11/FT) in the combo box cboBatch.

private void FormAddMarks_Load(object sender, EventArgs e) {

…

}

(3 marks)

ii. Complete the code below, for the two methods shown below

btnAddPhoto_Click and openImageFileDialog_FileOk. The first

method loads an open form dialog, named openImageFileDialog to

select the picture of the student, and the second method is to display

the photo after it has been selected.

private void btnAddPhoto_Click (object sender, EventArgs e) { … }

private void openImageFileDialog_FileOk(object sender, CancelEventArgs e) { …

}

(5 marks)

iii. Complete the code below, which calculates the total marks for the

student, combining the both assignments and the examination marks.

Note that total marks cannot exceed 100%, since both assignments

accounts for 40% and examination accounts for 60%. Use an

appropriate try-catch statement.

private void btnTotal_Click(object sender, EventArgs e)

{ …

}

(5 marks)


iv. When the all the details have been inserted and the total marks

computed, clicking on the save button loads a save dialog named

saveFileDialog. The lecturer selects the text file to save all the student

details and clicks on save in the dialog box. Complete the code below,

so as to load the save dialog box and write all details in text file.

private void btn_save_Click(object sender, EventArgs e) {

… }

(8 marks)

c) As a future update to the application, the lecturer has asked you to remove

the calculate button, and find a way to automatically load the total marks in

the textbox txtTotal. Explain how you will proceed, you may provide an

algorithm in pseudocode.

(5 marks)

***END OF QUESTION PAPER***

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BSc (Hons) Software Engineering BSc (Hons) Computer ...Write VB.Net codes to implement the interface which displays a message box when the user clicks on the ‘Build Pizza’ button