ITF11006 .NET

Industrial Programming

Industrial Programming

• Guidelines– Development Guidelines– UX Guidelines

• Quality Measures– Code Metrics– Code Analyses

• Robustness– Error handling (exceptions)– Resource handling

Guidelines

• Design Guidelines for Developing Class Libraries (http://msdn.microsoft.com/en-us/library/ms229042.aspx)

– Guidelines for Names• Capitalization Conventions (http://msdn.microsoft.com/en-us/library/ms229043(v=vs.100).aspx)

• Use Pascal casing ALLWAYS• Except, use camel casing for:

– parameter names– variables and (none-public) fields

– Member Design Guidelines• Choosing Between Properties and Methods

(http://msdn.microsoft.com/en-us/library/ms229054.aspx)

– Never public fields (except for structs)

• Documentation of code

Documentation of code

• Documentable Entities– Class / Struct– Method– …

• Cannot document Namespace through XML tag• Shows up in

– Object Browser– Intellisense– Library Documentation (http://msdn.microsoft.com/en-us/library/system.text.stringbuilder.aspx)

Documentation of code (cont.)• XML tags (http://msdn.microsoft.com/en-us/library/5ast78ax.aspx)

– summary– param– example– code– exception– returns

• GhostDoc (http://submain.com/products/ghostdoc.aspx)

Guidelines

• Design Guidelines for Developing Class Libraries (http://msdn.microsoft.com/en-us/library/ms229042.aspx)

– Guidelines for Names• Capitalization Conventions (http://msdn.microsoft.com/en-us/library/ms229043(v=vs.100).aspx)

– Member Design Guidelines• Choosing Between Properties and Methods

(http://msdn.microsoft.com/en-us/library/ms229054.aspx)

• Documentation of code• UX Guidelines

UX Guidelines

• Windows Size– Default– Min– Max

• Windows Position• Resizing must work!• Clean layout• Shortcuts• Tab-order

Industrial Programming

• Guidelines– Development Guidelines– UX Guidelines

• Quality Measures– Code Metrics– Code Analyses

• Robustness– Error handling (exceptions)– Resource handling

Code Metrics

• Cyclomatic complexity– Structural complexity of code– Calculates number of different code paths– High values requires more unit tests to cover all paths

• Class Coupling– Measures the Efferent Coupling, the number of classes this

method depends on– High coupling means brittle, likely to change, probably

unfocused and lack of responsibility

• Lines of Code– Based on IL, so approximate, but better than source– Excludes white space, comments, braces, types etc.

Code Metrics (cont.)

• Maintainability Index:– A weighted number based on Halstead volume, cyclomatic

complexity and lines of code– Maintainability Index = MAX(0,(171 - 5.2 * ln(Halstead

Volume) - 0.23 * (Cyclomatic Complexity) - 16.2 * ln(Lines of Code))*100 / 171)

– A green rating is between 20 and 100 and indicates that the code has good maintainability. A yellow rating is between 10 and 19 and indicates that the code is moderately maintainable. A red rating is a rating between 0 and 9 and indicates low maintainability.

Code MetricsMetric Green Yellow Red

Maintainability Index 100-60 60-40 <40

Cyclomatic complexity <10 10-20 >20

Class Coupling <10 10-20 >20

Lines of Code <10 10-30 >30

• Use MS official sample– “Image slideshow in full screen mode”

(http://code.msdn.microsoft.com/CSImageFullScreenSlideShow-79e29568)

Code Metrics – VS 2010

Code Metrics – Excel

Code Analyses

• Rule Set• Rule Action• Automatic / Manual execution• Use from Start

Code Analyses - Settings

Code Analyses – Results/Fix

Code Analyses – Requirements• Microsoft Minimum Recommended Rules

+Microsoft.Naming (All)• HiOf.Net.ruleset

Industrial Programming

• Guidelines– Development Guidelines– UX Guidelines

• Quality Measures– Code Metrics– Code Analyses

• Robustness– Defensive Programming– Error handling (exceptions)– Resource handling

Defensive Programming

• Handle anticipated deviations– Missing Directory / File– Lack of database connectivity– Lost database connection

• Verify input data– Do not let the user enter erroneous data

• Guard against SQL injection– Use SQL procedures / bind variables

Exception Handling

Catching Exceptions

Exceptions

• Design Guidelines for Exceptions (http://msdn.microsoft.com/en-us/library/ms229014.aspx)

• Do not throw System.Exception• Inherit from System.Exception• End with Exception

User Defined Exceptions

public class NewException : BaseException, ISerializable

{

public NewException()

{

// Add implementation.

}

public NewException(string message)

{

// Add implementation.

}

public NewException(string message, Exception inner)

{

// Add implementation.

}

// This constructor is needed for serialization.

protected NewException(SerializationInfo info, StreamingContext context)

{

// Add implementation.

}

}

Exceptions

• Exception handling• Throwing exceptions• Exception info– Message– InnerException

• Library code rethrows/do not catch• Clients shall handle exceptions

Resource handling

• Unmanaged resources– Implementing

• IDisposable

– Consuming• Using vs. try/finally

• Closing vs Disposing– Database, files, …