DataObjectFieldAttribute Costruttori

public:
 DataObjectFieldAttribute(bool primaryKey);

public DataObjectFieldAttribute(bool primaryKey);

new System.ComponentModel.DataObjectFieldAttribute : bool -> System.ComponentModel.DataObjectFieldAttribute

Public Sub New (primaryKey As Boolean)

Parametri

public:
 DataObjectFieldAttribute(bool primaryKey, bool isIdentity);

public DataObjectFieldAttribute(bool primaryKey, bool isIdentity);

new System.ComponentModel.DataObjectFieldAttribute : bool * bool -> System.ComponentModel.DataObjectFieldAttribute

Public Sub New (primaryKey As Boolean, isIdentity As Boolean)

Parametri

public:
 DataObjectFieldAttribute(bool primaryKey, bool isIdentity, bool isNullable);

public DataObjectFieldAttribute(bool primaryKey, bool isIdentity, bool isNullable);

new System.ComponentModel.DataObjectFieldAttribute : bool * bool * bool -> System.ComponentModel.DataObjectFieldAttribute

Public Sub New (primaryKey As Boolean, isIdentity As Boolean, isNullable As Boolean)

Parametri

Esempio

Nell'esempio di codice seguente viene illustrato come applicare a DataObjectFieldAttribute una proprietà esposta pubblicamente per identificare i metadati associati alla proprietà . In questo esempio il NorthwindEmployee tipo espone tre proprietà di dati: EmployeeID, FirstNamee LastName. L'attributo DataObjectFieldAttribute viene applicato a tutte e tre le proprietà, ma solo l'attributo EmployeeID della proprietà indica che è la chiave primaria per la riga di dati.

public class NorthwindEmployee
{
  public NorthwindEmployee() { }

  private int _employeeID;
  [DataObjectFieldAttribute(true, true, false)]
  public int EmployeeID
  {
    get { return _employeeID; }
    set { _employeeID = value; }
  }

  private string _firstName = String.Empty;
  [DataObjectFieldAttribute(false, false, true)]
  public string FirstName
  {
    get { return _firstName; }
    set { _firstName = value; }
  }

  private string _lastName = String.Empty;
  [DataObjectFieldAttribute(false, false, true)]
  public string LastName
  {
    get { return _lastName; }
    set { _lastName = value; }
  }
}

Public Class NorthwindEmployee

  Public Sub New()
  End Sub

  Private _employeeID As Integer
  <DataObjectFieldAttribute(True, True, False)> _
  Public Property EmployeeID() As Integer
    Get
      Return _employeeID
    End Get
    Set(ByVal value As Integer)
      _employeeID = value
    End Set
  End Property

  Private _firstName As String = String.Empty
  <DataObjectFieldAttribute(False, False, False)> _
  Public Property FirstName() As String
    Get
      Return _firstName
    End Get
    Set(ByVal value As String)
      _firstName = value
    End Set
  End Property

  Private _lastName As String = String.Empty
  <DataObjectFieldAttribute(False, False, False)> _
  Public Property LastName() As String
    Get
      Return _lastName
    End Get
    Set(ByVal value As String)
      _lastName = value
    End Set
  End Property

End Class

public:
 DataObjectFieldAttribute(bool primaryKey, bool isIdentity, bool isNullable, int length);

public DataObjectFieldAttribute(bool primaryKey, bool isIdentity, bool isNullable, int length);

new System.ComponentModel.DataObjectFieldAttribute : bool * bool * bool * int -> System.ComponentModel.DataObjectFieldAttribute

Public Sub New (primaryKey As Boolean, isIdentity As Boolean, isNullable As Boolean, length As Integer)

Parametri