C# Attributes

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What general kinds of attributes are there?: Predefined or custom.
What are the reserved attributes?: There are only two reserved attributes, Conditional and Obsolete.
Give an example of attribute usage, i.e., show a code snippet.: [Obsolete] public myClass { ... };

//This class should not be used.

or

[Conditional("Debug")] void DebugTrace() { ... }

Compile this method only if the Debug flag is defined.
What types of declarations can an attribute target?: Most declarations. A complete list can be found at: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vclrfattributetargets.asp
Can all attributes be used on all targets?: No. Most attributes must be attached to a specific language element. However, there are some global attributes.
To what elements do global attributes apply?: Assemblies or modules.
Name two global assembly attributes.: The following are found in the System.Reflection namespace.

AssemblyConfigurationAttribute
AssemblyCultureAttribute
AssemblyDescriptionAttribute
AssemblyKeyFileAttribute
AssemblyKeyNameAttribute
AssemblyDelaySignAttribute
AssemblyTitleAttribute
AssemblyVersionAttribute
What System.Reflection attributes are used with the strong name tool?: AssemblyKeyFileAttribute
AssemblyKeyNameAttribute
AssemblyDelaySignAttribute

Use the file name from the SN.exe (strong name utility) as arguments to these attributes.
How can you create your own custom attributes.: Create a class that inherits form the System.Attribute class.
Give a quick code example that builds a custom attribute: using System;
//restrict attribute usage to classes only
[AttributeUsage(AttributeTargets.Class)]
public class myClass(string astring)
{
//constructor
public Collector(string astring
{
this.astring = astring;
date = 1993;
}
//private versions of parameters
public short date;
string astring;
}
How is name space collision avoided when building attributes?: All attributes implicitly end with "Attribute". Thus "Collector" from the example will be treated as "CollectorAttribute" by the system.
What System.Reflection method is used to retrieve attribute information from Attributes?: Either
public virtual object[] GetCustomAttributes(bool);
or
public static Attribute GetCustomAttribute(Assembly, Type);
What are the two types of parameters that are supported by Attribute Classes?: Positional Parameters:
a. Must be specified when the attribute is used.
b. Must be set by constructor.

Named Parameters:
a. optional
b. when specified name of parameter must be specified. i.e., foo = foovalue
c. named parameters are similar to properties. But defined at the class level.
What types may an attribute argument be?: Simple numeric types including char.
string
System.Type
enums
object
one-dimensional arrays of any of the above types.
Where can you find the acceptable values for the AttributeTargets attribute?: AttributeTargets enumeration
If you wanted to create a attribute that could be used more than once how would you do it?: [AttributeUsage(AttributeTargets.All,AllowMultiple = true)]
Note: AllowMultiple must be named.

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Number of cards 16