mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/EditorOptionAttribute.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation.PropertyEditing
   6 {
   7     using System.Runtime;
   8     using System.Collections;
   9
  10     [Fx.Tag.XamlVisible(false)]
  11     [AttributeUsage(AttributeTargets.Property, AllowMultiple = true)]
  12     public sealed class EditorOptionAttribute : Attribute
  13     {
  14         public string Name { get; set; }
  15         public object Value { get; set; }
  16         //TypeId is needed so that multiple EditorOptionsAttribute could be added to the same property
  17         public override object TypeId
  18         {
  19             get
  20             {
  21                 return new EditorOptionsAttributeTypeId
  22                 {
  23                     BaseTypeId = base.TypeId,
  24                     Name = this.Name,
  25                     Value = this.Value
  26                 };
  27             }
  28         }
  29
  30         public static bool TryGetOptionValue(IEnumerable attributes, string optionName, out object optionValue)
  31         {
  32             foreach (Attribute attribute in attributes)
  33             {
  34                 EditorOptionAttribute optionAttribute = attribute as EditorOptionAttribute;
  35                 if (optionAttribute != null && optionAttribute.Name.Equals(optionName))
  36                 {
  37                     optionValue = optionAttribute.Value;
  38                     return true;
  39                 }
  40             }
  41             optionValue = null;
  42             return false;
  43         }
  44
  45         //A class to uniquely identify a name-value pair
  46         class EditorOptionsAttributeTypeId
  47         {
  48             public object BaseTypeId { get; set; }
  49             public string Name { get; set; }
  50             public object Value { get; set; }
  51
  52             public override bool Equals(object obj)
  53             {
  54                 EditorOptionsAttributeTypeId that = obj as EditorOptionsAttributeTypeId;
  55                 if (that == null) return false;
  56                 return this.BaseTypeId == that.BaseTypeId &&
  57                     string.Equals(this.Name, that.Name) &&
  58                     object.Equals(this.Value, that.Value);
  59             }
  60
  61             public override int GetHashCode()
  62             {
  63                 return
  64                     (BaseTypeId == null ? 0 : BaseTypeId.GetHashCode()) ^
  65                     (Name == null ? 0 : Name.GetHashCode()) ^
  66                     (Value == null ? 0 : Value.GetHashCode());
  67             }
  68         }
  69     }
  70 }