class/System.ComponentModel.Composition/src/ComponentModel/System/ComponentModel/Composition/ExportAttribute.cs

   1 // -----------------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 // -----------------------------------------------------------------------
   4 using System;
   5 using System.ComponentModel.Composition.Hosting;
   6 using System.Diagnostics.CodeAnalysis;
   7
   8 namespace System.ComponentModel.Composition
   9 {
  10     /// <summary>
  11     ///     Specifies that a type, property, field, or method provides a particular export.
  12     /// </summary>
  13     [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes")]
  14     [AttributeUsage(AttributeTargets.Class | AttributeTargets.Field | AttributeTargets.Property | AttributeTargets.Method,
  15                     AllowMultiple = true, Inherited = false)]
  16     public class ExportAttribute : Attribute
  17     {
  18         /// <summary>
  19         ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
  20         ///     type or member marked with this attribute under the default contract name.
  21         /// </summary>
  22         /// <remarks>
  23         ///     <para>
  24         ///         The default contract name is the result of calling
  25         ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the type of the
  26         ///         property or field, or the type itself, that is marked with this attribute.
  27         ///     </para>
  28         ///     <para>
  29         ///         The contract name is compared using a case-sensitive, non-linguistic comparison
  30         ///         using <see cref="StringComparer.Ordinal"/>.
  31         ///     </para>
  32         /// </remarks>
  33         public ExportAttribute()
  34             : this((string)null, (Type)null)
  35         {
  36         }
  37
  38         /// <summary>
  39         ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
  40         ///     type or member marked with this attribute under a contract name derived from the
  41         ///     specified type.
  42         /// </summary>
  43         /// <param name="contractType">
  44         ///     A <see cref="Type"/> of which to derive the contract name to export the type or
  45         ///     member marked with this attribute, under; or <see langword="null"/> to use the
  46         ///     default contract name.
  47         /// </param>
  48         /// <remarks>
  49         ///     <para>
  50         ///         The contract name is the result of calling
  51         ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on
  52         ///         <paramref name="contractType"/>.
  53         ///     </para>
  54         ///     <para>
  55         ///         The default contract name is the result of calling
  56         ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the type of the
  57         ///         property or field, or the type itself, that is marked with this attribute.
  58         ///     </para>
  59         ///     <para>
  60         ///         The contract name is compared using a case-sensitive, non-linguistic comparison
  61         ///         using <see cref="StringComparer.Ordinal"/>.
  62         ///     </para>
  63         /// </remarks>
  64         public ExportAttribute(Type contractType)
  65             : this((string)null, contractType)
  66         {
  67         }
  68
  69         /// <summary>
  70         ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
  71         ///     type or member marked with this attribute under the specified contract name.
  72         /// </summary>
  73         /// <param name="contractName">
  74         ///      A <see cref="String"/> containing the contract name to export the type or member
  75         ///      marked with this attribute, under; or <see langword="null"/> or an empty string
  76         ///      ("") to use the default contract name.
  77         /// </param>
  78         /// <remarks>
  79         ///     <para>
  80         ///         The default contract name is the result of calling
  81         ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property or field
  82         ///         type, or the type itself that this is marked with this attribute.
  83         ///     </para>
  84         ///     <para>
  85         ///         The contract name is compared using a case-sensitive, non-linguistic comparison
  86         ///         using <see cref="StringComparer.Ordinal"/>.
  87         ///     </para>
  88         /// </remarks>
  89         public ExportAttribute(string contractName)
  90             : this(contractName, (Type)null)
  91         {
  92         }
  93
  94         /// <summary>
  95         ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
  96         ///     type or member marked with this attribute under the specified contract name.
  97         /// </summary>
  98         /// <param name="contractName">
  99         ///      A <see cref="String"/> containing the contract name to export the type or member
 100         ///      marked with this attribute, under; or <see langword="null"/> or an empty string
 101         ///      ("") to use the default contract name.
 102         /// </param>
 103         /// <param name="contractType">
 104         ///     A <see cref="Type"/> of which to derive the contract name to export the type or
 105         ///     member marked with this attribute, under; or <see langword="null"/> to use the
 106         ///     default contract name.
 107         /// </param>
 108         /// <remarks>
 109         ///     <para>
 110         ///         The default contract name is the result of calling
 111         ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property or field
 112         ///         type, or the type itself that this is marked with this attribute.
 113         ///     </para>
 114         ///     <para>
 115         ///         The contract name is compared using a case-sensitive, non-linguistic comparison
 116         ///         using <see cref="StringComparer.Ordinal"/>.
 117         ///     </para>
 118         /// </remarks>
 119         public ExportAttribute(string contractName, Type contractType)
 120         {
 121             this.ContractName = contractName;
 122             this.ContractType = contractType;
 123         }
 124
 125         /// <summary>
 126         ///     Gets the contract name to export the type or member under.
 127         /// </summary>
 128         /// <value>
 129         ///      A <see cref="String"/> containing the contract name to export the type or member
 130         ///      marked with this attribute, under. The default value is an empty string ("").
 131         /// </value>
 132         public string ContractName { get; private set; }
 133
 134         /// <summary>
 135         ///     Get the contract type that is exported by the member that this attribute is attached to.
 136         /// </summary>
 137         /// <value>
 138         ///     A <see cref="Type"/> of the export that is be provided. The default value is
 139         ///     <see langword="null"/> which means that the type will be obtained by looking at the type on
 140         ///     the member that this export is attached to.
 141         /// </value>
 142         public Type ContractType { get; private set; }
 143     }
 144 }