Starting out with Visual C# (4th Edition)
4th Edition
ISBN: 9780134382609
Author: Tony Gaddis
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Question
Chapter 4, Problem 9AW
Program Plan Intro
List boxes:
List box controls help to show the list of items which enables the user to choose an item from the list.
- The user may choose one of the items from the list, causing the item to appear selected at runtime.
- The selected items will be displayed on ListBox control.
Get the items from ListBox control:
The item which is selected by user from ListBox is stored into ListBox’s SelectedItem property.
Steps to determine the selected item in Listbox:
If anyone tries to get the value when ListBox’s SelectedItem is empty, then it will occur with an exception.
- Always ensure that item is selected before reading an item in the SelectedItem. The items stored in ListBox with index value.
- This is done by “SelectedIndex” property.
- The item index is stored into SelectedIndex property.
- The index is a number to determine the position of Items in ListBox.
- If first item means index value is “0”, second means “1”, and so on. If there is no item in ListBox, then the index value is set to “-1”.
- The following example code checks whether the SelectedIndex property is “-1” or not.
if(courseListBox.SelectionIndex != -1)
{
selectedProduct = productListBox.SelectedItem.ToString();
}
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
How can you read the selected item from a ListBox while preventing an exception from occurring if no item is selected?
How do you read the currently chosen item from a ListBox without throwing an exception if no item is selected?
Assume nameListBox is a ListBox control. Write code that reads the selected item from the ListBox. Be sure to prevent an exception from occurring in case no item has been selected.
Chapter 4 Solutions
Starting out with Visual C# (4th Edition)
Ch. 4.1 - What is a control structure?Ch. 4.1 - What is a decision structure?Ch. 4.1 - Prob. 4.3CPCh. 4.1 - Prob. 4.4CPCh. 4.1 - What types of relationships between numeric values...Ch. 4.1 - Write an if statement that determines whether the...Ch. 4.1 - Write an if statement that determines whether the...Ch. 4.2 - Prob. 4.8CPCh. 4.2 - In an if-else statement, under what circumstances...Ch. 4.2 - Write an if-else statement that works like this:...
Ch. 4.3 - Convert the following set of nested if-else...Ch. 4.4 - Prob. 4.12CPCh. 4.4 - Prob. 4.13CPCh. 4.4 - Assume the variables a = 2, b = 4, and c = 6....Ch. 4.4 - Explain how short-circuit evaluation works with...Ch. 4.4 - Write an if statement that displays the message...Ch. 4.4 - Write an if statement that displays the message...Ch. 4.5 - Prob. 4.18CPCh. 4.5 - Prob. 4.19CPCh. 4.6 - If the following code were part of a complete...Ch. 4.6 - If the following code were part of a complete...Ch. 4.7 - Prob. 4.22CPCh. 4.7 - If a TryParse method successfully converts the...Ch. 4.7 - Prob. 4.24CPCh. 4.7 - Prob. 4.25CPCh. 4.9 - Prob. 4.26CPCh. 4.9 - If several CheckBox controls have been created in...Ch. 4.9 - Prob. 4.28CPCh. 4.10 - Convert the following if-else-if code to a switch...Ch. 4.11 - Prob. 4.30CPCh. 4.11 - Prob. 4.31CPCh. 4.11 - Prob. 4.32CPCh. 4 - A __________ structure executes a set of...Ch. 4 - A __________ structure provides one alternative...Ch. 4 - A(n) __________ expression has a value of either...Ch. 4 - The symbols , , and == are all __________...Ch. 4 - A __________ structure tests a condition and then...Ch. 4 - You use a(n) __________ statement to write a...Ch. 4 - You use a(n) __________ statement to write a dual...Ch. 4 - A ____________ decision structure is written...Ch. 4 - , ||, and ! are __________ operators. a....Ch. 4 - A compound Boolean expression created with the...Ch. 4 - A compound Boolean expression created with the...Ch. 4 - The __________ operator takes a Boolean expression...Ch. 4 - A __________ is a Boolean variable that signals...Ch. 4 - Prob. 14MCCh. 4 - Prob. 15MCCh. 4 - Prob. 16MCCh. 4 - The __________ section of a switch statement is...Ch. 4 - A ListBoxs index numbering starts at __________....Ch. 4 - You can use the __________ property to determine...Ch. 4 - The __________ property holds the item that is...Ch. 4 - Prob. 1TFCh. 4 - A single-alternative decision structure tests a...Ch. 4 - The if-else statement is a dual-alternative...Ch. 4 - A decision structure can be nested inside another...Ch. 4 - A compound Boolean expression created with the ...Ch. 4 - Prob. 6TFCh. 4 - Multiple CheckBox controls in the same GroupBox...Ch. 4 - The test expression in a switch statement can be a...Ch. 4 - If an item is not selected in a ListBox, the...Ch. 4 - Prob. 10TFCh. 4 - What is meant by the term conditionally executed?Ch. 4 - You need to test a condition and then execute one...Ch. 4 - Briefly describe how the operator works.Ch. 4 - Briefly describe how the || operator works.Ch. 4 - Prob. 5SACh. 4 - What is a flag and how does it work?Ch. 4 - What are the two arguments that you pass to a...Ch. 4 - How do you determine in code whether a RadioButton...Ch. 4 - Prob. 9SACh. 4 - Prob. 10SACh. 4 - Write an if statement that assigns 20 to the...Ch. 4 - Write an if statement that assigns 0 to the...Ch. 4 - Write an if-else statement that assigns 0 to the...Ch. 4 - Write nested decision structures that perform the...Ch. 4 - Write an if-else statement that displays Speed is...Ch. 4 - Write an if-else statement that determines whether...Ch. 4 - Prob. 7AWCh. 4 - Rewrite the following if-else-if statement as a...Ch. 4 - Prob. 9AWCh. 4 - Roman Numeral Converter Create an application that...Ch. 4 - Mass and Weight Scientists measure an objects mass...Ch. 4 - Magic Dates The date June 10, 1960, is special...Ch. 4 - Color Mixer The colors red, blue, and yellow are...Ch. 4 - Prob. 5PPCh. 4 - Book Club Points Serendipity Booksellers has a...Ch. 4 - Software Sales A software company sells a package...Ch. 4 - Body Mass Index Program Enhancement In Programming...Ch. 4 - Change for a Dollar Game Create a change-counting...Ch. 4 - Fat Percentage Calculator One gram of fat has 9...Ch. 4 - Time Calculator Create an application that lets...Ch. 4 - Workshop Selector The following table shows a...
Knowledge Booster
Similar questions
- C++HurdleWords The HurdleWords class is mostly provided to you. HurdleWords is constructed from two files in the data/ folder: ● valid_guesses.txt (all 5 letter guesses considered to be valid words to guess), and ● valid_hurdles.txt (all words that may be selected to be the secret Hurdle.) ● Note: you may edit both text files if you’d like to add custom words to your game. HurdleWords stores all potential valid Hurdles from valid_hurdles.txt into a vector of strings (valid_hurdles_), and all valid guesses from valid_guesses.txt into an unordered set of strings (valid_guesses_). A set is simply a data structure that contains no duplicates and allows for a speedy lookup to check if a given element exists within the set. Because there are over 10,000 valid guesses, we store them in an unordered set to leverage their speediness, as you will need to check if a user-submitted guess is considered valid (i.e. their guess is considered a valid guess in the dictionary). You are responsible for…arrow_forwardReminder: This is a bare code without any class or function/method heading around the code. Just the nested looparrow_forwardWrite a statement that retrieves the image stored at index 0 from an ImageList control named slideShowImageList and displays it in a PictureBox control named slideShowPictureBox.arrow_forward
- woulb you please help me work on this program C# visual Studio. Given the following: Listbox Name: lstDemo private void btnDisplay_Click(object sender, EventArgs e){ //Your code goes here }Using a for loop code the statements that will display the values below in the above listbox with each one on a new line. Use the btnDisplay_Click event to place you code in. The output should look like this in the listbox:510152025arrow_forwardPlease provide answer in C#: Slot Machine Simulation A slot machine is a gambling device into which the user inserts money and then pulls a lever (or presses a button). The slot machine then displays a set of random images. If two or more of the images match, the user wins an amount of money that the slot machine dispenses back to the user. Create an application that simulates a slot machine. Figure 8-23 (on page 539 of your book) shows an example of how the form should look. The application should let the user enter into a TextBox the amount of money he or she is inserting into the machine. When the user clicks the Spin button, the application should display three randomly selected symbols. (Slot machines traditionally display fruit symbols. You will find a set of fruit symbols attached to this dropbox for your use - from the Student Sample Programs provided by the book author.) If none of the randomly displayed images match, the program should inform the user that he or she has won…arrow_forwardWhat is the best way to delete the contents of a ListBox control?arrow_forward
- Group 2/12 Problem – Population Create an application that predicts the approximate size of a population of organisms. The application should use textboxes to allow the user to enter the starting number of organisms, the average daily population increase (as a percentage), and the number of days the organisms will be left to multiply. Use a ListBox to display the population size for each day of the simulation. If the user clicks the Save button, save the current prediction to a file. Group 3/7 Problem – Dice Simulatorarrow_forwardThe condition that controls a Do While loop must be true for the loop to be executed. Checkboxes are used in designing the user interface for situations where the user may choose only one of a few choices. Boolean variables are often used to improve the readability / clarity of the program code. For Next loops can have both negative and positive step values. If no item has been selected in a listbox, the SelectedIndex property of the listbox will have a value of zero. A Boolean variable must be initialized after the If instruction in which it is used is executed. A post-test loop is a loop that is designed to be executed at least once. In coding a Select Case instruction, the only thing that may appear after the Select Case keywords is a variable. A Do loop begins with the keyword Do and ends with the keyword Loop. The condition that controls a Do Until loop must be true for the loop to be executed. Radio buttons are used in designing the user interface for situations where the user…arrow_forwardDistance File Modify the Distance Calculator program that you wrote for Programming Problem 1 so it writes its output to a file instead of displaying it in a ListBox control. Open the file in Notepad or Visual Studio to confirm the output.arrow_forward
- PYTHON: In this assignment, you will use all of the graphics commands you have learned to create an animated scene. Your program should have a clear theme and tell a story. You may pick any school-appropriate theme that you like. The program must include a minimum of: 5 circles 5 polygons 5 line commands 2 for loops 1 global variable You may wish to use the standard code for simplegui graphics below: import simplegui def draw_handler(canvas): frame = simplegui.create_frame('Testing', 600, 600) frame.set_canvas_background("Black") frame.set_draw_handler(draw_handler) frame.start()arrow_forwardVBA - EXCEL Engine – optional – this indicates the solving method that needs to be used to get to a solution. 1 for the Simplex LP method, 2 for the GRG Nonlinear method, or 3 for the Evolutionary method. This corresponds to the Select a Solving Method dropdown list in the Solver Parameters dialog box EngineDesc – optional -this is an alternate way of selecting the solving method – here you would type the strings “Simplex LP”, “GRG Nonlinear” or “Evolutionary”. This also corresponds to the Select a Solving Method dropdown list in the Solver Parameters dialog box What happens when the code demonstrates: Engine:=1, EngineDesc:="GRG Nonlinear" ?arrow_forwardA ListBox control is a container in which data may be stored. How many items are currently stored in this container?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Microsoft Visual C#Computer ScienceISBN:9781337102100Author:Joyce, Farrell.Publisher:Cengage Learning,EBK JAVA PROGRAMMINGComputer ScienceISBN:9781337671385Author:FARRELLPublisher:CENGAGE LEARNING - CONSIGNMENTEBK JAVA PROGRAMMINGComputer ScienceISBN:9781305480537Author:FARRELLPublisher:CENGAGE LEARNING - CONSIGNMENT
Microsoft Visual C#
Computer Science
ISBN:9781337102100
Author:Joyce, Farrell.
Publisher:Cengage Learning,
EBK JAVA PROGRAMMING
Computer Science
ISBN:9781337671385
Author:FARRELL
Publisher:CENGAGE LEARNING - CONSIGNMENT
EBK JAVA PROGRAMMING
Computer Science
ISBN:9781305480537
Author:FARRELL
Publisher:CENGAGE LEARNING - CONSIGNMENT