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Showing posts from July, 2013

Closures in C# vs JavaScript -
Same But Different

Closure in a Nutshell Closures are a Software phenomenon which exist in several languages, in which methods declared inside other methods (nested methods), capture variables declared inside the outer methods. This behavior makes captured variables available even after the outer method's scope has vanished. The following pseudo-code demonstrates the simplest sample: Main() //* Program starts from here { Closures(); } AgeCalculator() { int myAge = 30; return() => { //* Returns the correct answer although AgeCalculator method Scope should have ordinarily disappear return myAge++; }; } Closures() { Func ageCalculator = AgeCalculator(); //* At this point AgeCalculator scopeid cleared, but the captured values keeps to live Log(ageCalculator()); //* Result: 30 Log(ageCalculator()); //* Result: 31 } JavaScript and C# are two languages that suppo

Understanding DateTime.ParseExact

When searching information about DateTime.ParseExact all documentations and blogs mention that the 'dateString' and the 'formatString' must be identical with the same date & time separators and format. Although true, it's not the a precise description of what is going on under the hoods. Some times when needed this rule can be bypassed. I will explain later how. For now lets see the steel thread: string dateString = "2012-01-01 13:30" string formatString = "yyyy-MM-dd HH:mm"; DateTime.ParseExact(dateString,formatString ,currentCultureFormatter) string dateString = "2012 01~01 13|30" string formatString = "yyyy MM~dd HH|mm"; DateTime.ParseExact(dateString,formatString ,currentCultureFormatter) string dateString = "2012-01|01 13~30" string formatString = "yyyy-MM|dd HH~mm"; DateTime.ParseExact(dateString,formatString ,currentCultureFormatter)

Formatting Data with IFormatProvider & ICustomFormatter

This post provides an internal overview of IFormatProvider & ICustomFormatter interfaces, and they way they are handled by .NET. IFormatProvider is a .NET Framework Interface that should be used, by implementing its single public object GetFormat(Type) method, when there is a need to implement custom formatting of data like String and DateTime. The public object GetFormat(Type) method simply returns an object that in turns is available to supply all available information to continue the formatting process. The Type passed in by the Framework is meant to give the implementor a way to decide which type to return back. Its like a Factory Method Design Pattern where the "formatType" is the type expected to be returned. class MyProvider : IFormatProvider { public object GetFormat(Type formatType) { object result = null; //* Factory Method if (formatType == typeof( ICustomFormatter)) //* Some object, will be d