Lý thuyết trắc nghiệm windows forms

You add the following design-time component to the form + SqlConnection object name EmpConn + SqlDataAdapter object name EmpDA + DataSet object name EmpDS + Five TextBox controls to hold

Windows Form

1 Which of the following is not a possible value for the RowState property of a DataRow object?

2

The Windows Form classes are located in the namespace

a) System.Windows.Forms c) System.WinForms

b) System.WindowsForms d) Windows.Forms

3

The _ argument and the _ argument are always passed as parameters to events for a control (choose 2)

a) System.Object

b) System.EventArgs

c) System.EventHandler

d) System.Controls

4

You have Visual Studio NET to develop a Windows-based application that interacts with a Microsoft SQL Server database Your application contains a form name EmployeeForm You add the following design-time component to the form

+ SqlConnection object name EmpConn

+ SqlDataAdapter object name EmpDA

+ DataSet object name EmpDS

+ Five TextBox controls to hold the values exposed by EmpDS

At design-time, you set DataBindings property of each TextBox control to appropriate column in the DataTable object of EmpDS When you test this application you can successfully connect to the database However, no data

is displayed in any TextBox

You need to modify your application code ensure that data is displayed appropriately Which behavior should occur while the EmployeeForm.Load event handler is running?

a) Execute the BeginInit method of EmpDS

b) Execute the Open method of EmpConn

c) Execute the FillSchema method of EmpDA and pass in EmpDS

d) Execute the Fill method of EmpDA and pass in EmpDS

5

Which of the following events is best suitable to validate the data?

a) KeyUp

b) Validated

c) Validating

d) LostFocus

6 You use Visual Studio NET to create a Windows-based application The application includes a form name CertK, which displays statistical date in graph format You use a custom graphing control that does not support resizing You must ensure that users cannot resize, minimize or maximize CertK Which three actions should you take? (choose 3)

a) Set CertK.MinimizeBox to False

b) Set Cert.MaximizeBox to false

c) Set Cert.ControlBox to false

d) Set Cert.ImeMode to Disabled

e) Set Cert.WindowState to Maximized

f) Set Cert.FormBorderStyle to one of the Fixed Styles

7

You develop a Visual Studio NET application that dynamically adds controls to its form at runtime You include the following statement at the top of your file:

using System.Windows.Forms;

In addition, you create the following code to add Button controls:

Button tempButton = new Button();

tempButton.Text = NewButtonCaption;

tempButton.Name = NewButtonName;

tempButton.Left = NewButtonLeft;

tempButtonTop = NewButtonTop;

this.Controls.Add(tempButton);

tempButton.Click += new EventHandler(ButtonHandler);

Variables are passed into the routine to supply values for the Text, Name, Left, Top properties

When you compile this code, you receive an error message indicating that ButtonHandler is not declared

You need to add a ButtonHandler routine to handle the Click event for all dynamically added Button controls Which declaration should you use for ButtonHandler?

a) public void ButtonHandler()

b) public void ButtonHandler(System.Windows.Forms.Button sender)

c) public void ButtonHandler(System.Object sender)

d) public void ButtonHandler(System.Windows.Forms.Button sender, System.EventArgs e)

e) public void ButtonHandler(System.Object sender, System.EventArgs e)

8

Your application uses a DataSet object to maintain a working set of data for your users Uses frequently change information in the DataSet object

Before you update your database, you must run data validation code on all user changes

You need to identify the data rows that contain changes First you create a DataView object What should you do next?

a) Set the RowStateFilter.CompareTo method

b) Set the RowStateFilter.Equals method

c) Set the RowStateFilter property to CurrentRow

d) Set the RowStateFilter property to ModifiedCurrent

9

You need to develop a Windows form that provides online help for users You want the help functionality to be available when users press F1 key

Help text will be displayed in a popup window for the textbox has focus

To implement this functionality, you need to call a method of HelpProvider control and pass the text box and the help text What should you do ?

a) SetShowHelp

b) SetHelpString

c) SetHelpKeyword

d) ToString

10 You use Visual Studio Net to develop a Windows-based application Your application will display customer order information from a Microsoft SQL Server database The orders will be display on Windows Form that includes a

DataGrid control which is bound to a DataView object Users will be able to edit order information directly in the DataGird control

You must give users the option of displaying only edited customer orders and updated values in the DataGrid What should you do?

a) Set the RowStateFilter property of the DataView object to DataViewRowState.ModifiedOriginal

b) Set the RowStateFilter property of the DataView object to DataViewRowState.ModifiedCurrent

c) Set the RowFilter property of the DataView object to DataViewRowState.ModifiedOriginal.

d) Set the RowFilter property of the DataView object to DataViewRowState.ModifiedCurrent

11

You use Visual Studio.Net to develop a Microsoft Windows-based application Your application contains a form named CustomerForm, which is includes the following design-time controls:

• SQL Connection object named CustConnection

• SQL DataAdapter object named CustDataAdapter

• DataSet object named CustomerDataSet

• Five TextBox controls to hold the values exposed by CustomerDatSet

• Button control named saveButton

At design time you set the DataBindings properties of each TextBox control to the appropriate column in the DataTable object of CustomerDataSet

When the application runs, users must be able to edit the information displayed in the text boxes All user changes must be saved to the appropriate database when saveButton is executed The event handler for saveButton includes the following code segment:

CustDataAdapter.Update(CustomerDataSet);

You test the application However, saveButton fails to save any values edited in the text boxes You need to correct this problem

What should your application do?

a) Call the InsertCommand method of CustDataAdapter

b) Call the Update method of CustDataAdapter and pass in CustConnection

c) Before calling the Update method, ensure that a row position change occurs in CustomerDataSet

d) Reestablish the database connection by calling the Open method of CustConnection

12

You are deploping a Window-based application that logs hours worked by employees Your design goals require you to maximize application performance and minimize impact on server resources

Your need to implement a SqlCommand object that will send a SQL INSERT action query to a database each time a user makes a new entry

To create a function named LineItemInsert, you write the following code (Line numbers are included for reference only)

01 : public int LineItemInsert(int empID, int projectID,

02 : decimal hrs, SqlConnection con)

03 : {

04 : string SQL;

05 : int Ret;

06 :

07 : SQL = String.Format (

08 : “INSERT INTO TimeEntries (EmpID, ProjectID, Hours)”

09 + 10 : “VALUES ({0},{1},{2})”,

11 : empID, projectID, hrs);

12 : SqlCommand cmd = new SqlCommand(SQL, con);

13 :

14 : //Insert new code

15 : }

You code must execute the SQL INSERT action query and verify the number of database records that are affected

by the query

Which code segment should you add on line 14 ?

a) con.Open();

Ret = cmd.ExecuteNonQuery(); con.Close(); return Ret;

b) con.Open(); Ret = cmd.ExecuteScalar(); con.Close(); return Ret;

c) SqlDataReader reader; con.Open(); reader = cmd.ExecuteReader();

con.Close(); return reader.RecordsAffected;

d) SqlDataReader reader; con.Open(); reader = cmd.ExecuteReader();

con.Close(); return reader.GetValue();

The _ event of the Form control is used to perform tasks such as allocating resources used by the form

a) Activate

b) Load

c) Allocate

d) Activated

14

When a Data Form is created using the Data Form Wizard, which of the following classes are used by default?

(choose 4 )

a) OleDbDataReader

b) OleDbConnection

c) OleDbCommand

d) OleDbDataWriter

e) OleDbDataAdapter

15

To create an instance of the Font class using existing Font and FontStyle, the constructor is:

a) public Font(Font f, FontStyle fs);

b) public Font(string fontname, float size);

c) public void Font(Font f, FontStyle fs);

d) public void Font(string fontname, float size);

16

Which control is used to display a short, customized help message for individual controls on a form?

a) ToolClass

b) HelpTool

c) HelpText

d) ToolTip

17

Statement 1: Tree View displays folders, drives etc

Statement 2: List View displays current folder contents

a) Both the statements are true

b) Only Statement 1 is true

c) Only Statement 2 is true

d) both the statements are false

18

Which class represents shortcut menus that can be displayed when the user clicks the right mouse button over a control or area of the form?

a) Menu

b) FileMenu

c) ContextMenu

d) ToolsMenu

19 Name the object which notifies other objects about an event?

a) Publisher

b) Subscriber

c) Consumer

d) Tester

20

Leo would like to populate a select dropdown combo box with data in a data store He wants a fast, forward only, read-only database connection using ADO.NET

Given the above scenario, which one of the following objects should Leo use?

a) A DataAdatpter object c) A DataReader object

b) A Command object d) A Connection object

21

Which class is the base class for all the controls that can be used in Windows Forms?

a) Objects

b) Forms

c) Controls

d) Control

22

Which of the following statements about event handlers is not true?

a) Event handlers cannot be removed dynamically

b) Event handlers are methods that handle events

c) Event handlers can handle multiple events

d) Multiple event handlers can be associated with an event

23

Which of the following namespaces defines the Trace and Debug classes?

a) System.Diagnostics

b) System.Collection

c) System.Security

d) System.ComponentModel

24

By setting the _ in a control, I can make sure that my code is not change if someone inherits my form

a) the Private value of the Modifiers property

b) the Unchanged value of the Modifiers property

c) the Restricted value of the Modifiers property

d) the Limited value of the Modifiers property

25 You are using Visual Studio.Net to develop a Windows- based application that contains a single form This form contains a label control named labelUser and a textbox control named textUser, labelUser displays a caption that identifies the purpose of textUser You want to write code that enables users to place focus in textUser when they press Alt + U This key combination should be identified to users in the display of labelUser

Which 3 actions should you take? (choose 3)

a) Set labelUser.UserMnemonic to True

b) Set labelUser.CauseValidation to True

c) Set textUser.CauseValidation to True

d) Set textUser.TabIndex to exactly one number more than labelUser.TabIndex

e) Set labelUser.Text to “&User”

26

You have created a Class Library of Custom User controls and Forms You want to use this class library as the foundation for your Windows application project

How can you reference it?

a) In the class View, right click on the project and select “Add Inherited Control” for user controls or select “Add Inherited Form” for Forms Name the component and click Open.Select component in the inheritance picker dialog box

b) In the Solution Explorer, right-click on the project and select “Add Inherited Control” for user controls or select

“Add Inherited Form” for Forms Name the component and click Open.Select component in the inheritance picker dialog box

c) From the Menu select “Project\ Add Inherited Control” for user controls or select “Project\ Add Inherited Form” for forms Name the component and click Open Select component in the inheritance picker dialog box

d) From the Menu select “Build\ Add Inherited Control” for user controls or select “Build\ Add Inherited Form” for forms Name the component and click Open Select component in the inheritance picker dialog box

27

You use Visual Studio.Net to develop a Windows-based application for a women’s college Your application will display student’s information from a Microsoft SQL Server database The information will be displayed on a Windows Form in a data grid named dg1 DataGrid1 is bound to a DataView object The Windows form includes a button control named displayStudent When users click this button, dgl must display only student information whose PaidFees value is set to True

How would you achieve this?

a) Set the RowFilter property of the dg1 object to “PaidFees = True”

b) Set the RowStateFilter property of the dg1 object to “PaidFees = True”

c) Set the RowFilter property of the DataView object to “PaiFees = True”

d) Set the RowStateFilter property of the DataView object to “PaiFees = True”

28

You use Visual Studio.Net to create a Windows-based application The application includes a form that several controls, including a button named exitButton After you finish designing the form, you select all controls and then select Lock Controls from the Format menu least possible effort, and without disrupting the other controls

First you select exitButton in the Windows Forms Designer What should you do next?

a) Set the Locked property to False

Set the Size property to the required size

Set the Locked property to True

b) Set the Locked property to False

Use this mouse to resize the control

Set the Locked property to True

c) Set the Size property to the required size

d) Use this mouse to resize the control

You develop a Windows-based application that includes the following code segment (Line numbers are included for reference only)

01 private void Password_Validating(object sender,

02 System.ComponentModel.CancelEventArgs e)

03 {

04 if(ValidCertKingPassword() == false)

05 {

06 // insert new code

07 }

08 }

You must ensure that users cannot move control focus away from textPassword if ValidCertKingPassword returns a value of False You will add the required code on line 6

a) e.Cancel = true;

b) sender = name;

c) password.AcceptsTab = false;

d) password.CausesValidation = false;

30

You use Visual Studio.Net to create a data entry form The form enables users to edit personal information such as address an telephone number The form contains a text box named textPhoneNumber

If a user enters an invalid telephone number, the form must notify the user of the error You create a function named IsValidPhone that validates the telephone number entered You include an ErrorProvider control named ErrorProvider1 in your form

Which additional code segment should you use?

a) private void textPhone_Validating(object sender, System.ComponentModel.CancelEventArgs e) {

if(!IsValidPhone()) {

errorProvider1.SetError(textPhone, “Invalid Phone”);

}}

b) private void textPhone_Validated(object sender, System.EventArgs e) {

if(!IsValidPhone()) {

errorProvider1.SetError(textPhone, “Invalid Phone”);

}}

c) private void textPhone_Validating(object sender, System.ComponentModel.CancelEventArgs e) {

if(!IsValidPhone()) {

errorProvider1.GetError(textPhone);

}}

d) private void textPhone_Validated(object sender, System.EventArgs e) {

if(!IsValidPhone()) {

errorProvider1.GetError(textPhone);

}}

e) private void textPhone_Validating(object sender, System.ComponentModel.CancelEventArgs e) {

if(!IsValidPhone()) {

errorProvider1.UpdateBinding();

}}

f) private void textPhone_Validated(object sender, System.EventArgs e) {

if(!IsValidPhone()) {

errorProvider1.UpdateBinding();

}}

31 You develop a Windows-based application Its users will view and edit employee attendance data The application uses a DataSet object named customerDataSet to maintain the data while users are working with it

After a user edits data, business rule validation must be performed by a middle-tier component named Certk Component You must ensure that your application sends only edited data rows from customDataSet to CertK Component

Which code segment should you use?

a) DataSet changeDataSet = new DataSet();

if(customDataSet.HasChanges) {

CertK Component.Validate(changeDataSet); }

b) DataSet changeDataSet = new DataSet();

if(customDataSet.HasChanges) {

CertK Component.Validate(customDataSet); }

c) DataSet changeDataSet = customDataSet.GetChanges();

CertK Component.Validate(changeDataSet);

d) DataSet changeDataSet = customDataSet.GetChanges();

CertK Component.Validate(customDataSet);

32

You develop a new sales analysis application that reuses existing data access components One of these components returns a DataSet object that contains the data for all customer orders for the previous years

You want your application to display orders for individual product numbers Users will specify the appropriate product numbers at runtime

What should you do?

a) Use the DataSet.Reset method

b) Set the RowFilter property of the DataSet object by using a filter expression

c) Create a DataView object and set the RowFilter property by using a filter expression

d) Create a DataView object and set the RowStateFilter property by using a filter expression

33

You develop a Windows-based application which uses a DataSet object that contains two DataTable objects The application will display data from two data tables One table contains customer information, which must be

displayed in a data-bound ListBox control The other table contains order information which must be displayed in a DataGrid control

You need to modify the application to enable the list box functionality

What should you do?

a) Use the DataSet.Merge method

b) Define primary keys for the Data Table objects

c) Create foreign key constraint on the DataSet object

d) Add a DataRelation object to the Relations collection of the DataSet object

34

You use Visual Studio.Net to create a control that will be used on serveral forms in your application

It is a custom label control that retrieves and displays your company’s current stock price The control will be displayed on many forms that have different backgrounds You want the control to show as much of the underlying forms as possible You want to ensure that only the stock price is visible The rectangular control itself should not

be visible

You need to add code to the Load event of the control to fulfill these requirements Which two code segments should you use? (Each correct answer presents part of the solution Choose 2)

a) this.BackColor = Color.Transparent;

b) this.ForeColor = Color.Transparent;

c) this.BackImage = null;

d) this.SetStyle(ControlStyles.UserPaint, false);

e) this.SetStyle(ControlSyles.SupportsTransparentBackColor, true);

35

When a Windows Application project is created in Visual C#, a form is created automatically with the class name as

a) Class1

b) Form1

c) Form0

d) ClassA

The and class has properties that hold the SQL statements to select, insert, update and delete data from the database (choose 2)

a) OleDbDataAdapter

b) SqlDataAdapter

c) OracleDataAdapter

d) OdbcDataAdapter

37

The method is used to create the Graphics object

a) CreateGraphics

b) Create

c) CreateGraph

d) DrawGraph

38

The _ event of the PrintDocument class is trigged immediately before each PrintPage event occurs

a) QueryPageSettings

b) PrintPage

c) BeginPrint

d) StartPrint

39

is used to display text or data in the form of nodes arranged in a hierarchical order?

a) ListView

b) TreeView

c) TaskView

d) NodeView

40

Which namespace does the class ListView belong to?

a) System.Windows.Drawing

b) System.Windows.Forms

c) System.Windows.Paints

d) System.Windows.Lists

41

Which of the following statements are True with respect to Data Set in ADO.Net? (choose 2)

a) DataSet is an in-memory cache of records that can be visited/ modified any direction

b) The DataSet is a read only cursor

c) A DataSet can contain only two data tables at a time corresponding to a database table or view

d) A DataSet constitutes a “disconnected” view of the data present in the database

Select the features of a good user interface? (choose 3)

a) Easy to learn

b) Easy to use

c) Attractive

d) Easy to develop

e) Colorful

43

Which class is the base class for all the controls that can be used in Windows Forms?

a) Objects

b) Forms

c) Controls

d) Control

44

Which of the following techniques for creating a control is the easiest and least time-consuming?

a) Inheriting from an existing control

b) Inheriting from UserControl

c) Inherting from Control

d) Creating from scratch

45

Which of the following types of error occurs when the compiler is unable to compile a code?

a) Syntax error

b) Runtime error

c) Logical error

d) Debugging error

46

The property will allow you to loop through the collection of MdiChild forms in your application You can use the property to determine the number of open MdiChildren in your application

a) MdiChildren, MdiChildren.Length

b) MdiForms, MdiForms.Length

c) MdiChild, MdiChild.Length

d) MdiChildren, MdiChildren.No

47 You are developing an ERP application for Customer Officer You are working on the e-mail form of the Windows application You use the TabControl control and want it to always fill the forms You also want the form to be resizable

How can you efficiently implement this feature?