Newtonsoft.Json\Linq\ComponentModel\JPropertyDescriptor.cs

#region License

// Copyright (c) 2007 James Newton-King

//

// Permission is hereby granted, free of charge, to any person

// obtaining a copy of this software and associated documentation

// files (the "Software"), to deal in the Software without

// restriction, including without limitation the rights to use,

// copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the

// Software is furnished to do so, subject to the following

// conditions:

//

// The above copyright notice and this permission notice shall be

// included in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

// OTHER DEALINGS IN THE SOFTWARE.

#endregion

#if !SILVERLIGHT

using System;

using System.ComponentModel;

using Newtonsoft.Json.Utilities;

namespace Newtonsoft.Json.Linq.ComponentModel

{

  /// <summary>

  /// Represents a view of a <see cref="JProperty"/>.

  /// </summary>

  public class JPropertyDescriptor : PropertyDescriptor

  {

    private readonly Type _propertyType;

    /// <summary>

    /// Initializes a new instance of the <see cref="JPropertyDescriptor"/> class.

    /// </summary>

    /// <param name="name">The name.</param>

    /// <param name="propertyType">Type of the property.</param>

    public JPropertyDescriptor(string name, Type propertyType)

      : base(name, null)

    {

      ValidationUtils.ArgumentNotNull(name, "name");

      ValidationUtils.ArgumentNotNull(propertyType, "propertyType");

      _propertyType = propertyType;

    }

    private static JObject CastInstance(object instance)

    {

      return (JObject)instance;

    }

    /// <summary>

    /// When overridden in a derived class, returns whether resetting an object changes its value.

    /// </summary>

    /// <returns>

    /// true if resetting the component changes its value; otherwise, false.

    /// </returns>

    /// <param name="component">The component to test for reset capability. 

    ///                 </param>

    public override bool CanResetValue(object component)

    {

      return false;

    }

    /// <summary>

    /// When overridden in a derived class, gets the current value of the property on a component.

    /// </summary>

    /// <returns>

    /// The value of a property for a given component.

    /// </returns>

    /// <param name="component">The component with the property for which to retrieve the value. 

    ///                 </param>

    public override object GetValue(object component)

    {

      JToken token = CastInstance(component)[Name];

      //if (token is JValue)

      //  return ((JValue) token).Value;

      return token;

    }

    /// <summary>

    /// When overridden in a derived class, resets the value for this property of the component to the default value.

    /// </summary>

    /// <param name="component">The component with the property value that is to be reset to the default value. 

    ///                 </param>

    public override void ResetValue(object component)

    {

    }

    /// <summary>

    /// When overridden in a derived class, sets the value of the component to a different value.

    /// </summary>

    /// <param name="component">The component with the property value that is to be set. 

    ///                 </param><param name="value">The new value. 

    ///                 </param>

    public override void SetValue(object component, object value)

    {

      JToken token = (value is JToken) ? (JToken) value : new JValue(value);

      CastInstance(component)[Name] = token;

    }

    /// <summary>

    /// When overridden in a derived class, determines a value indicating whether the value of this property needs to be persisted.

    /// </summary>

    /// <returns>

    /// true if the property should be persisted; otherwise, false.

    /// </returns>

    /// <param name="component">The component with the property to be examined for persistence. 

    ///                 </param>

    public override bool ShouldSerializeValue(object component)

    {

      return false;

    }

    /// <summary>

    /// When overridden in a derived class, gets the type of the component this property is bound to.

    /// </summary>

    /// <returns>

    /// A <see cref="T:System.Type"/> that represents the type of component this property is bound to. When the <see cref="M:System.ComponentModel.PropertyDescriptor.GetValue(System.Object)"/> or <see cref="M:System.ComponentModel.PropertyDescriptor.SetValue(System.Object,System.Object)"/> methods are invoked, the object specified might be an instance of this type.

    /// </returns>

    public override Type ComponentType

    {

      get { return typeof(JObject); }

    }

    /// <summary>

    /// When overridden in a derived class, gets a value indicating whether this property is read-only.

    /// </summary>

    /// <returns>

    /// true if the property is read-only; otherwise, false.

    /// </returns>

    public override bool IsReadOnly

    {

      get { return false; }

    }

    /// <summary>

    /// When overridden in a derived class, gets the type of the property.

    /// </summary>

    /// <returns>

    /// A <see cref="T:System.Type"/> that represents the type of the property.

    /// </returns>

    public override Type PropertyType

    {

      get { return _propertyType; }

    }

    /// <summary>

    /// Gets the hash code for the name of the member.

    /// </summary>

    /// <value></value>

    /// <returns>

    /// The hash code for the name of the member.

    /// </returns>

    protected override int NameHashCode

    {

      get

      {

        // override property to fix up an error in its documentation

        int nameHashCode = base.NameHashCode;

        return nameHashCode;

      }

    }

  }

}

#endif