wpftoolkit/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Core/Utilities/ReflectionHelper.cs

/************************************************************************

   Extended WPF Toolkit

   Copyright (C) 2010-2012 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   This program can be provided to you by Xceed Software Inc. under a
   proprietary commercial license agreement for use in non-Open Source
   projects. The commercial version of Extended WPF Toolkit also includes
   priority technical support, commercial updates, and many additional 
   useful WPF controls if you license Xceed Business Suite for WPF.

   Visit http://xceed.com and follow @datagrid on Twitter.

  **********************************************************************/

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq.Expressions;
using System.Reflection;

namespace Xceed.Wpf.Toolkit.Core.Utilities
{
  internal static class ReflectionHelper
  {
    /// <summary>
    /// Check the existence of the specified public instance (i.e. non static) property against
    /// the type of the specified source object. If the property is not defined by the type,
    /// a debug assertion will fail. Typically used to validate the parameter of a 
    /// RaisePropertyChanged method.
    /// </summary>
    /// <param name="sourceObject">The object for which the type will be checked.</param>
    /// <param name="propertyName">The name of the property.</param>
    [System.Diagnostics.Conditional( "DEBUG" )]
    internal static void ValidatePublicPropertyName( object sourceObject, string propertyName )
    {
      if( sourceObject == null )
        throw new ArgumentNullException( "sourceObject" );

      if( propertyName == null )
        throw new ArgumentNullException( "propertyName" );

      System.Diagnostics.Debug.Assert( sourceObject.GetType().GetProperty( propertyName, System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.FlattenHierarchy | System.Reflection.BindingFlags.Public ) != null,
        string.Format( "Public property {0} not found on object of type {1}.", propertyName, sourceObject.GetType().FullName ) );
    }

    /// <summary>
    /// Check the existence of the specified instance (i.e. non static) property against
    /// the type of the specified source object. If the property is not defined by the type,
    /// a debug assertion will fail. Typically used to validate the parameter of a 
    /// RaisePropertyChanged method.
    /// </summary>
    /// <param name="sourceObject">The object for which the type will be checked.</param>
    /// <param name="propertyName">The name of the property.</param>
    [System.Diagnostics.Conditional( "DEBUG" )]
    internal static void ValidatePropertyName( object sourceObject, string propertyName )
    {
      if( sourceObject == null )
        throw new ArgumentNullException( "sourceObject" );

      if( propertyName == null )
        throw new ArgumentNullException( "propertyName" );

      System.Diagnostics.Debug.Assert( sourceObject.GetType().GetProperty( propertyName, System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.FlattenHierarchy | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic ) != null,
        string.Format( "Public property {0} not found on object of type {1}.", propertyName, sourceObject.GetType().FullName ) );
    }

    internal static bool TryGetEnumDescriptionAttributeValue( Enum enumeration, out string description )
    {
      try
      {
        FieldInfo fieldInfo = enumeration.GetType().GetField( enumeration.ToString() );
        DescriptionAttribute[] attributes = fieldInfo.GetCustomAttributes( typeof( DescriptionAttribute ), true ) as DescriptionAttribute[];
        if( ( attributes != null ) && ( attributes.Length > 0 ) )
        {
          description = attributes[ 0 ].Description;
          return true;
        }
      }
      catch
      {
      }

      description = String.Empty;
      return false;
    }

    [DebuggerStepThrough]
    internal static string GetPropertyOrFieldName( MemberExpression expression )
    {
      string propertyOrFieldName;
      if( !ReflectionHelper.TryGetPropertyOrFieldName( expression, out propertyOrFieldName ) )
        throw new InvalidOperationException( "Unable to retrieve the property or field name." );

      return propertyOrFieldName;
    }

    [DebuggerStepThrough]
    internal static string GetPropertyOrFieldName<TMember>( Expression<Func<TMember>> expression )
    {
      string propertyOrFieldName;
      if( !ReflectionHelper.TryGetPropertyOrFieldName( expression, out propertyOrFieldName ) )
        throw new InvalidOperationException( "Unable to retrieve the property or field name." );

      return propertyOrFieldName;
    }

    [DebuggerStepThrough]
    internal static bool TryGetPropertyOrFieldName( MemberExpression expression, out string propertyOrFieldName )
    {
      propertyOrFieldName = null;

      if( expression == null )
        return false;

      propertyOrFieldName = expression.Member.Name;

      return true;
    }

    [DebuggerStepThrough]
    internal static bool TryGetPropertyOrFieldName<TMember>( Expression<Func<TMember>> expression, out string propertyOrFieldName )
    {
      propertyOrFieldName = null;

      if( expression == null )
        return false;

      return ReflectionHelper.TryGetPropertyOrFieldName( expression.Body as MemberExpression, out propertyOrFieldName );
    }
  }
}