Chapter 4
How to test and debug
an ASP.NET application
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 1
Objectives
Applied
 Test a file-system web site with the ASP.NET development
server or IIS.
 Create and test a local IIS web site.
 Test a web site using more than one browser.
 Use the debugging techniques presented in this chapter to
determine the cause of runtime or logical errors in any of the
applications you develop.
Knowledge
 Explain how a file-system web site can be run under IIS.
 Describe how you can test your applications for concurrency
errors.
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 2
Objectives (continued)
 Describe the conditions under which an Exception Assistant
dialog box is displayed.
 Distinguish between break points and trace points.
 Describe the differences between the three Step commands that
you can use to control the execution of an application: Step Into,
Step Over, and Step Out.
 Describe the primary use of the Autos, Locals, and Watch
windows.
 Describe the use of the Trace feature of ASP.NET.
 Describe the use of messages that are written directly to the HTTP
output stream.
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 3
The Order page displayed in the default browser
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 4
Three ways to run an application with debugging
 Click the Start Debugging button in the Standard toolbar
 Press F5
 Choose the DebugStart Debugging command
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 5
Three ways to run an application
without debugging
 Press Ctrl+F5
 Choose DebugStart Without Debugging
 Right-click a page in the Solution Explorer and choose View in
Browser.
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 6
Three ways to stop an application
that’s run with debugging
 Press Shift+F5
 Click the Stop Debugging button in the Debug toolbar
 Choose DebugStop Debugging
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 7
The Browse With dialog box
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 8
An Exception Assistant dialog box
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 9
The dialog box for selecting a local IIS web site
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 10
The dialog box for creating a virtual directory
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 11
The dialog box for specifying a web server
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 12
Limitations of the ASP.NET Development Server
 Can serve pages only to the local computer.
 Runs in current user’s security context, so it doesn’t accurately
test security issues.
 Can’t be configured as an SMTP server, so it can’t be used to
test email applications.
 Uses a randomly chosen port rather than the standard HTTP port
80.
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 13
Mozilla Firefox browser outside of Visual Studio
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 14
The Order page with a breakpoint
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 15
The Order page with a tracepoint
and the dialog box used to set it
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 16
Tracepoint output in the Output window
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 17
The Shopping Cart application in break mode
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 18
Commands in the Debug menu and toolbar
Command
Start/Continue
Break All
Stop Debugging
Restart
Show Next Statement
Step Into
Step Over
Step Out
Murach’s ASP.NET 4/C#, C4
Toolbar
Keyboard
F5
Ctrl+Alt+Break
Shift+F5
Ctrl+Shift+F5
F11
F10
Shift+F11
© 2011, Mike Murach & Associates, Inc.
Slide 19
The Code Editor window’s shortcut menu
 Run to Cursor
 Set Next Statement
 Show Next Statement
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 20
The Autos window
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 21
The Locals window
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 22
A Watch window
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 23
The Immediate window
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 24
Beginning of the trace output for the Cart page
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 25
Session and cookies information for the Cart page
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 26
A Page directive that enables tracing
<%@ Page Language="C#" AutoEventWireup="true"
CodeFile="Cart.aspx.cs"
Inherits="Cart" Trace="true" %>
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 27
Common members of the TraceContext class
Property
IsEnabled
Method
Write(message)
Write(category, message)
Warn(message)
Warn(category, message)
Murach’s ASP.NET 4/C#, C4
Description
True if tracing is enabled for the
page.
Description
Writes a message to the trace
output.
Writes a message to the trace
output with the specified
category.
Writes a message in red type to
the trace output.
Writes a message in red type to
the trace output with the
specified category.
© 2011, Mike Murach & Associates, Inc.
Slide 28
Code that writes a custom trace message
if (Trace.IsEnabled)
{
Trace.Write("Page_Load",
"Binding products drop-down list.");
}
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 29
Trace output that includes a custom message
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 30
The Cart page with output from Response.Write
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 31
Code that writes to the HTTP output stream
protected void Page_Load(object sender, EventArgs e)
{
this.GetCart();
if (!IsPostBack)
{
this.DisplayCart();
Response.Write("Items in cart =
" + cart.Count + "<br />");
}
}
Code that writes HTML output from another class
HttpContext.Current.Response.Write(
"Now updating file.<br />");
Murach’s ASP.NET 4/C#, C4
© 2011, Mike Murach & Associates, Inc.
Slide 32