OptionalFieldAttribute 類別

定義

指定可從序列化 (Serialization) 資料流中遺漏欄位,使 BinaryFormatterSoapFormatter 不會擲回例外狀況。Specifies that a field can be missing from a serialization stream so that the BinaryFormatter and the SoapFormatter does not throw an exception.

public ref class OptionalFieldAttribute sealed : Attribute
[System.AttributeUsage(System.AttributeTargets.Field, Inherited=false)]
[System.Runtime.InteropServices.ComVisible(true)]
public sealed class OptionalFieldAttribute : Attribute
type OptionalFieldAttribute = class
    inherit Attribute
Public NotInheritable Class OptionalFieldAttribute
Inherits Attribute
繼承
OptionalFieldAttribute
屬性

備註

這個屬性可讓您指定可序列化型別中的新欄位 (套用至的SerializableAttribute型別), BinaryFormatterSoapFormatter忽略。This attribute allows you to specify that new fields in a serializable type (a type to which the SerializableAttribute is applied to) are ignored by the BinaryFormatter or the SoapFormatter. 這會啟用針對繼承應用程式 (序列化資料) 所建立之類型的版本相容序列化。This enables version-tolerant serialization of types created for older versions of an application that serializes data. 例如, 當格式器遇到不包含新欄位的版本所產生的資料流程時, 不會擲回任何例外狀況, 而且舊類型上的現有資料會正常處理。For example, when the formatters encounter a stream produced by a version that does not include the new fields, no exception is thrown, and the existing data on the older type is processed as normal.

建構函式

OptionalFieldAttribute()

初始化 OptionalFieldAttribute 類別的新執行個體。Initializes a new instance of the OptionalFieldAttribute class.

屬性

TypeId

在衍生類別中實作時,取得這個 Attribute 的唯一識別碼。When implemented in a derived class, gets a unique identifier for this Attribute.

(繼承來源 Attribute)
VersionAdded

取得或設定版本號碼以指出何時新增操作欄位。Gets or sets a version number to indicate when the optional field was added.

方法

Equals(Object)

傳回值,這個值指出此執行個體是否與指定的物件相等。Returns a value that indicates whether this instance is equal to a specified object.

(繼承來源 Attribute)
GetHashCode()

傳回這個執行個體的雜湊碼。Returns the hash code for this instance.

(繼承來源 Attribute)
GetType()

取得目前執行個體的 TypeGets the Type of the current instance.

(繼承來源 Object)
IsDefaultAttribute()

在衍生類別中覆寫時,表示這個執行個體的值是衍生類別的預設值。When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.

(繼承來源 Attribute)
Match(Object)

在衍生類別中覆寫時,會傳回值,表示這個執行個體是否等於指定物件。When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(繼承來源 Attribute)
MemberwiseClone()

建立目前 Object 的淺層複製。Creates a shallow copy of the current Object.

(繼承來源 Object)
ToString()

傳回代表目前物件的字串。Returns a string that represents the current object.

(繼承來源 Object)

明確介面實作

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

將一組名稱對應至一組對應的分派識別項 (Dispatch Identifier)。Maps a set of names to a corresponding set of dispatch identifiers.

(繼承來源 Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

擷取物件的類型資訊,可以用來取得介面的類型資訊。Retrieves the type information for an object, which can be used to get the type information for an interface.

(繼承來源 Attribute)
_Attribute.GetTypeInfoCount(UInt32)

擷取物件提供的類型資訊介面數目 (0 或 1)。Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(繼承來源 Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

提供物件所公開的屬性和方法的存取權。Provides access to properties and methods exposed by an object.

(繼承來源 Attribute)

適用於