Reflection yana ba da damar ga shirin duba da gyara nau'i, hanyoyi, da kaddarori a lokacin gudu — har ma da waɗanda ba a sani su a lokacin bugi. Attributes suna haɗa da metadata ta illantar zuwa gida da kayan aiki da kuma frameworks suna karantawa (sau da yawa ta hanyar reflection) don turawa jaki. Tare sun ba da karfi ga yawancin "sihiri" na .NET's framework (serialization, DI, ORMs, validation).
// examine a type's structure at runtime
Type type = typeof(User);
foreach (PropertyInfo prop in type.GetProperties())
Console.WriteLine($"{prop.Name}: {prop.PropertyType}");
foreach (MethodInfo method in type.GetMethods()) { }
// create instances and invoke members dynamically
object instance = Activator.CreateInstance(type); // create without knowing the type at compile time
PropertyInfo p = type.GetProperty("Name");
p.SetValue(instance, "Ann"); // set a property reflectively
Reflection yana ba da damar gida don gano da amfani da nau'i da saya — samarwa ta hanyar nau'i, karantawa/saita kaddarori, gayyata hanyoyi — wanda shi ne yadda frameworks suna aiki akan nau'ina ba tare da sanewa a gida ba.
// built-in and framework attributes attach metadata to code
[Obsolete("Use NewMethod instead")]
[Serializable]
public class OldClass { }
public class User
{
[Required] // validation attribute (ASP.NET)
[StringLength(100)]
public string Name { get; set; }
[JsonPropertyName("email_address")] // serialization attribute
public string Email { get; set; }
}
[HttpGet("/users/{id}")] // ASP.NET routing attribute
public User Get(int id) { }
Attributes suna illantar gida da metadata da frameworks suna karantawa don turawa jaki — ƙa'idodin bincike, sunan serialization, routing, da sauransu.
public class AuditAttribute : Attribute { public string Action; }
[Audit(Action = "delete")]
public void DeleteUser(int id) { }
// a framework reads the attribute via reflection and acts on it
var attr = method.GetCustomAttribute<AuditAttribute>();
if (attr != null) Log(attr.Action); // wrap/log/intercept based on the metadata
Wan shine hanyar bayan ASP.NET ([HttpGet], [Authorize]), bincike ([Required]), serialization ([JsonPropertyName]), ORMs, da kuma jajjayen frameworks — suna nemi code da attributed ta hanyar reflection da wiring jaki.
Reflection da attributes sune na'ura bayan yawancin aiki-framework na .NET, saboda haka tunawa da su ya kasance da daraja don fahimta yadda frameworks suke aiki da kuma don al'amar ci gaba. Reflection yana ba da damar jaki na kowa, aiki mai sauki — duba da aiki akan nau'i a lokacin gudu ba tare da ilimi a lokacin bugi — wanda shi ne yadda injection na dogaro, serialization (JSON/XML libraries suna karantawa kaddarori), ORMs (taswira abubuwa zuwa tesabbin bayanai), da kuma jajjayen frameworks suke aiki akan nau'ina na dama. Attributes suna ba da illantar metadata waɗannan kayan aiki suna karantawa (ta hanyar reflection) don turawa jaki, saita tsawon ƙa'idar da fuskanci illantar ([Required] don bincike, [HttpGet] don routing, [JsonPropertyName] don serialization, [Authorize] don tsaro).
Tunawa da su yana bugi yadda ASP.NET Core, Entity Framework, bincike, serialization, da kuma jajjayen frameworks suke yin illantar "sihiri" na su — gane cewa attributes suna yatsa gida da reflection suna karantawa da aiki akan waɗancan alamomi.
Wan ilimi ya kasance da daraja don amfani da waɗannan frameworks da kyau, gina kayan aiki nau'i-framework naka ko ramanmu (custom attributes + reflection), da kuma fahimta jigon abubuwa (reflection ya fi karfe fiye da kiran kai tsaye da yana sallame wasu bugi-lokaci bincike, saboda haka ana amfani da shi da hankali).
While ci gaba da ba shi aiki na yau da kullun, tunawa da reflection da attributes ya kasance ilimi mai mahimmanci na manyan abubuwa don aiki da zuriya a .NET ecosystem — yana bayyana yadda frameworks da ke amfani da su kullun suke aiki a gida, yana ba da damar ci gaba metaprogramming, da kuma shine jimla mai alaka don fahimtar .NET's gida da gina ramanmu masu irinwa, attribute-driven, wanda ya sa ilmi wai ya kasance da daraja da ke bambanta masu karatu da hankali da .NET na zuriya.