This document discusses C# .NET strings and various methods that can be used on string variables including trim, contains, replace, and substring. Trim removes unwanted characters from the start and end of a string. Contains checks if a substring is within a string. Replace replaces occurrences of one substring with another. Substring extracts a portion of a string starting from a specified index for a given length.

1. Chapter 9C# .NET strings

2. What will we be learning?string variable and its methodstrimcontainremove and replacesubstring

3. string variable and its methodsstring stringVar = "Dear Mr Tan, how are you?";string anotherStringVar;anotherStringVar = stringVar.IntelliSense- shows you a list of Methods and Properties that are available for the variable

4. Full list of methods and properties >Mouse Over

5. Part 1 variable and methodsNew solution and project: SpfChapter9_stringsSave all and rename the project to "Part 1 variable and methods"Add a button and a textbox

6. Add codes into button click method:

8. Length property of string variableThis property return the number of characters in a stringIt also counts the blank spacesEg: stringVar.Length;Note that you don't need any round brackets, because it's a property not a method

9. trim methodTo trim unwanted characters from the string – used often to trim blank spaces at the start and the endTrim(): both at the start and the end

10. TrimEnd(): at the end

11. TrimStart(): at the startContinue from previous projectAdd another button and textboxAdd codes into the button click method

12. 3 blank spaces at the start and the end

14. Continue …

15. Trim()TrimEnd()

16. null => blank spaceTrim() same as Trim(null)TrimStart() same as TrimStart(null)TrimEnd() same as TrimEnd(null)

17. Trim other character

19. Trim more than one characters

21. Contains method

24. Replace methodSpell checker:Replace "mistak" with "mistake"Replace "teh" with "the"::

25. Continue

26. Add codes into button click method:

28. Substring methodintstartIndex => starting position to extract the substring(start from 0)int length => length of the substring

29. ContinueAdd a button and textbox

30. Add codes for button click method: