Chapter 6-Lesson 3

• Font class along with Graphics.DrawString( ) method may be used to draw text on forms, Bitmaps and Images.
• StringAlignment.Near actually aligns text to Left.
• Font class has 13 constructor overloads.
• LineAlignment flag determines vertical alignment of text.

Chapter 4-Lesson 4

• BitArray class stores Boolean values in a resizable list. (Manually resizable using Length property)
• This class also supports standard operations such as AND, OR, XOR, etc.
• BitVector32 is a structure. It is not resizable, and is used to manipulate bits of, say an Int32.
• BitArray does not support Add( ) / Remove( ) methods. We use indexers instead.
• BitVector32 structure actually stores its value in its Data property which is an Int32. Any changes made to the bits would ultimately change the Data property.
• BitVector32 works on unsigned integers.
• Practical usage of BitVector32 include Bit Masking, Bit Packing, etc.
• Bit Packing allows storage of usual small numbers into one relatively large number to save space. (e.g. instead of using three Int16 numbers, we may pack them into one Int32)
• StringCollection and StringDictionary are strongly typed.
• StringCollection works identical to ArrayList, and StringDictionary works identical to HashTable except that both Key and Value must be strings.
• However, Keys in StringDictionary are case-Insensitive, meaning "fourth" and "Fourth" would lead to same Value.
• The CollectionsUtil class provides static methods for creating case-insensitive HashTable/SortedList.
• StringComparer object allows for creating Culture-Invariant collections.
• The NameValueCollection allows to store multiple Values per Key. Values can be retrieved by using Key or Index.
• This collection would behave like previous collections when items are added using indexer, but behaves differently (allows multiple Values per Key) when Add( ) method is used.
• It also supports retriving Value using Index number of Key. If a key has more than one Value, using index would return a comma seperated list.

Chapter 3-Lesson 1

• Regex class is used to match a string against a Regular Expression.
• When validating input, one must put the leading carat ( ^ ) to represent beginning of input and dollar ($) sign to represent end of input pattern so as to minimize the risk of human error.
• The carat (^) would match the expression at the beginning of any line in a multi-line string.
• Regular Expressions characters are case sensitive, even in VB.NET
• Tip: Use Verbatim strings (that begin with @ sign) to create regular expressions to avoid problems with back-slashes.
• Try to learn a few simple Regular Expressions for exam.
• Asterisk (*) means the preceding character must be present zero or more time, while plus (+) sign represents 1 or more times.
• To define a certain number of occurrence for a character use {n} notation after the character where n is the number of occurrences.
• We can also define min-max range for a character using {min,max} notation. We can also leave either as blank.
• Use question mark to make character optional. And Period (.) to represent reserved space for a single character.
• Use Table 3-3 in the MS Press book for further information.
• We may use Back-Referencing (using \k with a named group) to search for repeating characters or groups of characters.
• Use of RegexOptions.ECMAScript with any other options throws an Exception.