Change the output effect of different classes by declaring the attribute property

consoleapplication--Console Application

First create the base class:

usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespaceattribute_exercise{/// <summary>    ///comments here do not affect compilation and operation, only help developers/// </summary>      //[some Attribute] e.g.[Obsolete]//[Obsolete], [Obsolete (")], [Obsolete (" ", True/false)] Obsolete's constructor F12 view[Serializable] Public classBasicclass {//base class properties, Fields         Public intID {Set;Get; }  Public stringName {Set;Get; } }                 Public classAclass:basicclass {} Public classBclass:basicclass {} Public classcclass:basicclass {}}

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Next, customize a attribute:

usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespaceattribute_exercise{/// <summary>    ///Customizing a Attribute:somename+attribute///when used: [Somename]/// </summary>     Public classCustomizedattribute:attribute {//The following are the constructor functions         PublicCustomizedattribute () {//Empty        }         PublicCustomizedattribute (stringmsg) {                 }         PublicCustomizedattribute (stringMsgBOOLerr) {                     }        //Field         Public stringMSG;  Public BOOLERR; }     Public classEslecusomizedattribute:attribute {}}

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In the main portal:

usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespaceattribute_exercise{classProgram {Static voidMain (string[] args) {            //The main use of the inheritance mechanismBasicclass BC =NewBasicclass () {id=1, name="base class 1"}; Console.WriteLine ("base class id:{0}; base class class name: {1}", BC.ID,BC.            Name);        Console.ReadLine (); }    }}

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First look at the effect of the base class:

The following goes into the topic-How do you make these inheriting classes behave differently or effectively without changing the base class and its inheriting classes, simply by declaring attribute?

1. Statement attribute: added [customized] at BasicClass.cs line 23;

2. How to add the corresponding attribute:

usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Reflection;//ReflectionusingSystem.Text;usingSystem.Threading.Tasks;namespaceattribute_exercise{ Public classattributeactivities { Public Static voidOutput<t> (T t)wheret:basicclass {Type type=T.gettype (); Attribute Attribute= Type. GetCustomAttribute (typeof(Customizedattribute));//note using System.Reflection;            if(Attribute! =NULL&& attribute isCustomizedattribute) {Customizedattribute customizedattr= attribute asCustomizedattribute; Console.WriteLine ("the current class extra attribute:{0}", Customizedattr.tostring (). Substring (Customizedattr.tostring (). IndexOf (".")+1)); Console.WriteLine ("+++++++++++++++++++++++++++++++++++++++++++++++++"); }                    }    }}

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3. Invoke the method at the main entrance of the program:

usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespaceattribute_exercise{classProgram {Static voidMain (string[] args) {            //The main use of the inheritance mechanismBasicclass BC =NewBasicclass () {id=1, name="base class 1"}; Console.WriteLine ("base class id:{0}; base class class name: {1}", BC.ID,BC.            Name); Console.WriteLine ("*************************************************"); Attributeactivities.output<AClass> (NewAClass () {ID=2, Name="AClass"                            }); Console.WriteLine ("*************************************************"); Attributeactivities.output<BClass> (NewBclass () {ID=3, Name="Bclass"            }); Console.WriteLine ("*************************************************"); Attributeactivities.output<CClass> (NewCclass () {ID=4, Name="Cclass"            });        Console.ReadLine (); }    }}

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Results:

Does it feel magical? There is no modification to this inheriting class, which is a declaration, and then attaching the corresponding method implements the different attribute classes with different effects.

Readers can also expand their own other ways to try ...

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Change the output effect of different classes by declaring the attribute property