Framework Design Guidelines

Krzysztof CwalinaProgram ManagerMicrosoft Corporationhttp://blogs.msdn.com/kcwalina

Brad AbramsProduct Unit ManagerMicrosoft Corporationhttp://blogs.msdn.com/brada

Dow Jones Industrial Average

@ 9,000

Dow Jones Industrial Average

@ 9,000

Framework Design Framework Design Artifacts:Artifacts:• PropertiesProperties• Methods Methods • EventsEvents• ConstructorsConstructors

8

public class XmlFile {public class XmlFile { string filename; string filename; Stream data; Stream data; public XmlFile(string filename) { public XmlFile(string filename) { this.data = DownloadData(filename); this.data = DownloadData(filename); }}}}

public XmlFile(string filename) {public XmlFile(string filename) { this.filename = filename; this.filename = filename; } }

lazylazy

public class ArrayList {public class ArrayList { public int Count {get;} public int Count {get;}}}

EmployeeList l = FillList();EmployeeList l = FillList();for (int i = 0; i < l.Length; i++){for (int i = 0; i < l.Length; i++){ if (l.All[i] == x){...}if (l.All[i] == x){...}}}

if (l.GetAll()[i]== x) {...}if (l.GetAll()[i]== x) {...}

public Employee[] All {get{}}public Employee[] All {get{}}

public Employee[] GetAll() {}public Employee[] GetAll() {}

Moral: Use method if the operation is expensive Moral: Use method if the operation is expensive

Calling CodeCalling Code

24

Time to cut…Time to cut…

26

public class TheBase : Object {

public override string ToString() {

return “Hello from the Base";

}

}public class Derived : TheBase {

public override string ToString() {

return “Hello from Derived";

}

}

Derived d = new Derived();Console.WriteLine (d.ToString());

TheBase tb = d;Console.WriteLine (tb.ToString());

Object o = tb;Console.WriteLine (o.ToString());

All Virtual members should define a contractAll Virtual members should define a contractDon’t require clients to have knowledge of Don’t require clients to have knowledge of your overridingyour overridingShould you call the base?Should you call the base?

Barbara Liskov

public interface IComparable { int CompareTo(object obj);}

Careful dependency management is the necessary ingredient to successful evolution of frameworks. Without it, frameworks quickly deteriorate and are forced out of relevance prematurely.

BCLBCL

WPFWPF XMLXML

ReflectionReflection

49Climbing a mountain?Climbing a mountain?

50

Scaling a Scaling a peak?peak?

51Running across a desert?Running across a desert?

Falling into a Falling into a pit?pit?

Read the manual??Read the manual??

PPascalascalCCasing – Each asing – Each word starts with an word starts with an uppercase letteruppercase letter

ccamelamelCCasing – First asing – First word lower case, word lower case, others uppercaseothers uppercase

SCREAMING_CAPSSCREAMING_CAPS – – All upper case with All upper case with underscoresunderscores

public class MemberDoc{ public int CompareTo(object value) public string Name { get;}}

public class CMyClass {public class CMyClass { int CompareTo (object objValue) {..} int CompareTo (object objValue) {..} string lpstrName {get;} string lpstrName {get;} int iValue {get;} int iValue {get;}}}

Brad Abramshttp://blogs.msdn.com/brada

Krzysztof Cwalinahttp://blogs.msdn.com/kcwalina

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