Errata

Change the first line of the code listing from:

Regex r = new Regex (@"sausages?");

to:

Regex r = new Regex (@"sausages?" , RegexOptions.Compiled);

And in the paragraph that follows, change :

This is not just a syntactic convenience: under the covers, a RegEx instance uses lightweight code generation...

to:

RegexOptions.Compiled instructs the RegEx instance to use lightweight code generation...

The 2nd paragraph starts with:
'This enables monitoring for the current domain'.

According to MSDN write up on MonitoringIsEnabled = true, it means 'monitoring is enabled for all application domains for the current process'.

Note from the Author or Editor:
Change 'domain' to 'process'

2nd paragraph says 'HttpResponseMessage has a CopyToAsync method for writing ...

Actually it is the HttpContent class, not HttpResponseMessage, that has the CopyToAsync method being discussed.

Note from the Author or Editor:
Correct. Replace:

HttpResponseMessage has a CopyToAsync method...

with:

HttpContent has a CopyToAsync method...

public class RichTextBox : TextBox, IUndoable
{
public new void Undo() { Console.WriteLine ("RichTextBox.Undo"); }
}

should be:
public class RichTextBox : TextBox, IUndoable
{
public new void Undo() { Console.WriteLine ("RichTextBox.Undo"); }
}

It is illegal to declare Undo method with new modifier. The Undo method in derived class doesn't hide any method in it base class, since the explictily implemented Undo method is tranparent to TextBox.

Note from the Author or Editor:
Change

public new void Undo() { Console.WriteLine ("RichTextBox.Undo"); }

to:

public void Undo() { Console.WriteLine ("RichTextBox.Undo"); }

(delete the word 'new')

XDocument doc = XDocument.Load (@"Customers.xml");
XElement e = e.XPathSelectElement ("customers/customer[firstname='Jim']");
// Here is mistake! I think it should be:
XElement e = doc.XPathSelectElement ...

Note from the Author or Editor:
Correct: change 'e.XPathSelectElement...' to 'doc.XPathSelectElement...'

"ReadStartElement verifies that the current NodeType is StartElement"

There is no such member as StartElement in the XmlNodeType enum. It should be just Element.

Note from the Author or Editor:
Correct: replace StartElement with Element.

ZipFile class lives not in System.IO.Compression.dll, but in a System.IO.Compression.FileSystem.dll assembly.
Also, the compression results from running examples in several previous sections should be updated. It seems that compressing algorithms were improved considerably in 4.5, so, for instance, thousand long empty array now compresses to mere 11 and not 113 bytes.

Note from the Author or Editor:
Replace System.IO.Compression.dll with System.IO.Compression.FileSystem.dll

replace OperationCancelledOperation with OperationCancelledException

Note from the Author or Editor:
Change OperationCanceledOperation to OperationCanceledException

Note also that there's one 'l' in canceled.

In the <include> example, the ending tag is </para> but should be </include>.

The table shows the regular expression \s as "same as" expression [\n\r\t\f]...this is not true, since \s also will match a space character as well as a vertical tab and [\n\r\t\f] will not...easily fixed by adding these characters into that set: [\n\r\t\f\v ]

Note from the Author or Editor:
Replace [\n\r\t\f] with [\n\r\t\f\v ]

Actually, \s also matches the vertical tab (\v), so it should be something like: [\n\r\t\f\v ]

Note from the Author or Editor:
Replace [\n\r\t\f] with [\n\r\t\f\v ]

(note the space near the end)

The table shows the regular expression \s as "same as" expression [\n\\r\t\f]...this is not true, since \s also will match a space character and [\n\r\t\f] will not...easily fixed by adding a space into that set: [\n\r\t\f ]

Note from the Author or Editor:
Replace [\n\r\t\f] with [\n\r\t\f\v ]

(note space near end)

The third statement in the Main() function has:

Workbook workBook = excel.Workbooks.Add();

Since in the "usings" above we alias Microsoft.Office.Interop.Excel as "Excel", this line should actually read:

Excel.Workbook workBook = excel.Workbooks.Add();

In order to compile correctly.

Note from the Author or Editor:
Change:

Workbook workBook = excel.Workbooks.Add();

to

Excel.Workbook workBook = excel.Workbooks.Add();

And in the listing below, change

Workbook workBook = excel.Workbooks.Add (missing);

to

Excel.Workbook workBook = excel.Workbooks.Add (missing);

The table shows (and the paragraph above it implies) that the result type of Average for a float selector is double, but I have verified that the output type of Average for a float selector is, in fact, float.

Note from the Author or Editor:
That sentence and table that follows should read as follows:

Further, Average always returns either decimal, float or double, according to the following table:

Selector type | Result type
decimal | decimal
float | float
int, long, double | double


(The table needs another row inserted for float, and the mention of float in the last row should be removed.)