ColumnAttribute Class

Reference

Definition

Namespace:: System.Data.Linq.Mapping

Assembly:: System.Data.Linq.dll

Important

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Associates a class with a column in a database table.

public ref class ColumnAttribute sealed : System::Data::Linq::Mapping::DataAttribute

[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Property, AllowMultiple=false)]
public sealed class ColumnAttribute : System.Data.Linq.Mapping.DataAttribute

[<System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Property, AllowMultiple=false)>]
type ColumnAttribute = class
    inherit DataAttribute

Public NotInheritable Class ColumnAttribute
Inherits DataAttribute

Inheritance: Object

Attribute

DataAttribute
ColumnAttribute

Attributes: AttributeUsageAttribute

Examples

<Table(Name:="Employees")>  _  
Public Class Employees  
    Private _LastName As String  
    ' …  
    <Column(Storage:="_LastName", DbType:="NVarChar(20) NOT NULL", _  
        CanBeNull:=false)> _  
    Public Property LastName() As String  
        Get  
            Return Me._LastName  
        End Get  
        Set  
            If ((Me._LastName = value) _  
                = false) Then  
                Me.OnPropertyChanging("LastName")  
                Me._LastName = value  
                Me.OnPropertyChanged("LastName")  
            End If  
        End Set  
    End Property  
End Class

[Table(Name="Employees")]  
public class Employees  
{  
    private string _LastName;      
    // …  
    [Column(Storage="_LastName", DbType="NVarChar(20) NOT NULL",   
        CanBeNull=false)]  
    public string LastName  
    {  
        get  
        {  
            return this._LastName;  
        }  
        set  
        {  
            if ((this._LastName != value))  
            {  
                this.OnPropertyChanging("LastName");  
                this._LastName = value;  
                this.OnPropertyChanged("LastName");  
            }  
        }  
    }  
}

Remarks

Use this attribute to designate a member of an entity class to represent a column in a database table. You can apply this attribute to any field or property that is public, private, or internal.

Only those entity class members identified as columns are persisted when LINQ to SQL saves changes to the database.

Use commas to separate multiple properties on the attribute.

Constructors

ColumnAttribute()

Initializes a new instance of the ColumnAttribute class.

Properties

AutoSync	Gets or sets the AutoSync enumeration.
CanBeNull	Gets or sets whether a column can contain null values.
DbType	Gets or sets the type of the database column.
Expression	Gets or sets whether a column is a computed column in a database.
IsDbGenerated	Gets or sets whether a column contains values that the database auto-generates.
IsDiscriminator	Gets or sets whether a column contains a discriminator value for a LINQ to SQL inheritance hierarchy.
IsPrimaryKey	Gets or sets whether this class member represents a column that is part or all of the primary key of the table.
IsVersion	Gets or sets whether the column type of the member is a database timestamp or version number.
Name	Gets or sets the name of a column. (Inherited from DataAttribute)
Storage	Gets or sets a private storage field to hold the value from a column. (Inherited from DataAttribute)
TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)
UpdateCheck	Gets or sets how LINQ to SQL approaches the detection of optimistic concurrency conflicts.

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

Explicit Interface Implementations

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)	Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)	Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute)
_Attribute.GetTypeInfoCount(UInt32)	Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)	Provides access to properties and methods exposed by an object. (Inherited from Attribute)

Applies to

Jaa