Lesson 15 - Working With Spans of Time

Tutorial Series: Free C# Fundamentals via ASP.NET Web Apps

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This lesson will deal with a complex type that is related to DateTime, called TimeSpan. The TimeSpan type represents the amount of time elapsed between two DateTime objects. For example, if you want to determine how long you’ve been alive you could use today's date, along with your birthday, and the elapsed time in between would be represented using TimeSpan.

Step 1: Create a New Project

Begin by opening the provided project, or creating a project, calling it “CS-ASP_015,” and setting up Default.aspx with the following Server Controls, and programmatic IDs:

  1. okButton

  2. resultLabel


In the okButton_Click event, create a TimeSpan variable and assign it the result of the TimeSpan.Parse() method, similar to how we used the DateTime.Parse():


You see here that the Parse() method takes in a string input, but the hint as to what this method does is unclear. To better understand what we can use as a valid input argument in this method, let’s research it by navigating to Microsoft’s documentation for this method:


The most important documentation on this page shows us exactly how to format the string argument:

“The s parameter contains a time interval specification in the form:

[ws][-]{ d | [d.]hh:mm[:ss[.ff]] }[ws]

Elements in square brackets ([ and ]) are optional. One selection from the list of alternatives enclosed in braces ({ and }) and separated by vertical bars (|) is required. The following table describes each element.”


Using this guide, write out the intended formatting in a comment as a reminder. Pay extra care to the particular separator this method demands for each time element in the string - either a colon (:), or a period (.) :


Tip: This string appears to be formatted arbitrarily, and it appears that way because it is! Actually, to be precise, the programmer who wrote this method decided, somewhat arbitrarily, on this particular string formatting that the method accepts. As such, this is not a syntax pattern specific to C#.

Step 2: Use TimeSpan.Parse() to Return a TimeSpan

Using the comment as a guide, write an acceptable set of time elements as a string input for this method:


This is essentially assigning myTimeSpan with a TimeSpan that represents 1 Day, 2 Hours, 3 Minutes, and 30.5 Seconds. This doesn’t appear immediately useful, so let’s combine a TimeSpan with a DateTime to demonstrate its practical use:

What this is doing is:cs-asp-015---working-with-spans-of-time.007

  1. Store a DateTime – returned for the Parse() method – into myBirthday

  2. Take the DateTime given by DateTime.Now – which is the current date – and call the Subtract() method from it, inputting myBirthday as the required DateTime argument. And then store the returned result of that method into myAge.

That sequence may seem convoluted and that is partly because it mentions concepts that we haven’t completely covered yet. However, the code is represented in a way that is readable and, hopefully, clearly communicates its intent.

Tip: You can add a link to important documentation directly in your code by making it a comment:

TimeSpan Link

Now, by pressing ctrl+left-click on the link, you can view the web page directly inside of Visual Studio!

Step 3: Access Properties Available to a TimeSpan Variable

Now that we have a TimeSpan object, stored in myAge, we can comb through various properties of that TimeSpan (shown with the Intellisense icon that looks like a wrench):


The most interesting option from this list of methods and properties is to output the total days/months/hours within a given TimeSpan. Let’s output the TotalDays property that, because it is a double, needs to be converted to a string with ToString():



With that, you have most of what you need to know about working with time in C#. With these two types – DateTime and TimeSpan – you will be able to represent, both, a specific moment of time and an elapsed period of time between two moments, as well as the various operations you can perform on these two time elements. Keep these concepts in mind as we continue forward. Good job!

Related Articles in this Tutorial:

Lesson 1 - Series Introduction

Lesson 2 - Installing Visual Studio 2015

Lesson 3 - Building Your First Web App

Lesson 4 - Understanding What You Just Did

Lesson 5 - Working with Projects in Visual Studio

Lesson 6 - Simple Web Page Formatting in Visual Studio

Challenge 1

Solution 1

Lesson 7 - Variables and Data Types

Lesson 8 - Data Type Conversion

Lesson 9 - Arithmetic Operators

Lesson 10 - C# Syntax Basics

Challenge 2 - ChallengeSimpleCalculator

Solution - ChallengeSimpleCalculator

Lesson 11 - Conditional If Statements

Lesson 12 - The Conditional Ternary Operator

Challenge 3 - ChallengeConditionalRadioButton

Solution - Challenge Conditional RadioButton

Lesson 13 - Comparison and Logical Operators

Lesson 13 Challenge - First Papa Bob's Website

Solution - Challenge First Papa Bob's Website

Lesson 14 - Working with Dates and Times

Lesson 15 - Working With Spans of Time

Lesson 16 - Working with the Calendar Server Control

Challenge 4 - Challenge Days Between Dates

Solution - Challenge Days Between Dates

Lesson 17 - Page_Load and Page.IsPostBack

Lesson 18 - Setting a Break Point and Debugging

Lesson 19 - Formatting Strings

Challenge 5 - Challenge Epic Spies Assignment

Solution - Challenge Epic Spies Assignment

Lesson 20 - Maintaining State with ViewState

Lesson 21 - Storing Values in Arrays

Lesson 22 - Understanding Multidimensional Arrays

Lesson 23 - Changing the Length of an Array

Challenge 6 - Challenge Epic Spies Asset Tracker

Solution - Challenge Epic Spies Asset Tracker

Lesson 24 - Understanding Variable Scope

Lesson 25 - Code Blocks and Nested If Statements

Lesson 26 - Looping with the For Iteration Statement

Challenge 7 - Challenge For Xmen Battle Count

Solution - Challenge For Xmen Battle Count

Lesson 27 - Looping with the while() & do...while() Iteration Statements

Lesson 28 - Creating and Calling Simple Helper Methods

Lesson 29 - Creating Methods with Input Parameters

Lesson 30 - Returning Values from Methods

Lesson 31 - Creating Overloaded Methods

Lesson 32 - Creating Optional Parameters

Lesson 33 - Creating Names Parameters

Lesson 34 - Creating Methods with Output Parameters

Challenge 8 - Challenge Postal Calculator Helper Methods

Solution - Challenge Postal Calculator Helper Methods

Mega Challenge Casino

Solution - Mega Challenge Casino

Lesson 35 - Manipulating Strings

Challenge 9 - Phun With Strings

Solution - Challenge Phun With Strings

Lesson 36 - Introduction to Classes and Objects

Challenge - Hero Monster Classes Part 1

Solution - Hero Monster Classes Part 1

Challenge - Hero Monster Classes Part 2

Solution - Challenge Hero Monster Classes Part 2

Lesson 37 - Creating Class Files Creating Cohesive Classes and Code Navigation

Lesson 38 - Understanding Object References and Object Lifetime

Lesson 39 - Understanding the .NET Framework and Compilation

Lesson 40 - Namespaces and Using Directives

Lesson 41 - Creating Class Libraries and Adding References to Assemblies

Lesson 42 - Accessibility Modifiers, Fields and Properties

Lesson 43 - Creating Constructor Methods

Lesson 44 - Naming Conventions for Identifiers

Lesson 45 - Static vs Instance Members

Challenge 10 - Challenge Simple Darts

Solution - Challenge Simple Darts

Lesson 46 - Working with the List Collection

Lesson 47 - Object Initializers

Lesson 48 - Collection Initializers

Lesson 49 - Working with the Dictionary Collection

Lesson 50 - Looping with the foreach Iteration Statement

Lesson 51 - Implicitly-Typed Variables with the var Keyword

Challenge 11 - Challenge Student Courses

Solution - Challenge Student Courses

Mega Challenge War

Solution - Mega Challenge War

Lesson 52 - Creating GUIDs

Lesson 53 - Working with Enumerations

Lesson 54 - Understanding the switch() Statement

Lesson 55 - First Pass at the Separation of Concerns Principle

Lesson 56 - Understanding Exception Handling

Lesson 57 - Understanding Global Exception Handling

Lesson 58 - Understanding Custom Exceptions

Lesson 59 - Creating a Database in Visual Studio

Lesson 60 - Creating an Entity Data Model

Lesson 61 - Displaying the DbSet Result in an ASP.NET GridView

Lesson 62 - Implementing a Button Command in a GridView

Lesson 63 - Using a Tools-Centric Approach to Building a Database Application

Lesson 64 - Using a Maintenance-Driven Approach to Building a Database Application

Lesson 65 - Creating a New Instance of an Entity and Persisting it to the Database

Lesson 66 - Package Management with NuGet

Lesson 67 - NuGet No-Commit Workflow

Lesson 68 - Introduction the Twitter Bootstrap CSS Framework

Lesson 69 - Mapping Enum Types to Entity Properties in the Framework Designer

Lesson 70 - Deploying the App to Microsoft Azure Web Services Web Apps

Papa Bob's Mega Challenge

Papa Bob's Mega Solution Part 1 - Setting up the Solution

Papa Bob's Mega Solution Part 2 - Adding an Order to the Database

Papa Bob's Mega Solution Part 3 - Passing an Order from the Presentation Layer

Papa Bob's Mega Solution Part 4 - Creating the Order Form

Papa Bob's Mega Solution Part 5 - Adding Enums

Papa Bob's Mega Solution Part 6 - Creating an Order with Validation

Papa Bob's Mega Solution Part 7 - Calculating the Order Price

Papa Bob's Mega Solution Part 8 - Displaying the Price to the User

Papa Bob's Mega Solution Part 9 - Creating the Order Management Page


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