C# Expression.Equals方法代码示例

		public GroupBy (QueryBlock block, Expression elementSelector, QueryBlock elementBlock, Expression keySelector, Location loc)
			: base (block, keySelector, loc)
		{
			//
			// Optimizes clauses like `group A by A'
			//
			if (!elementSelector.Equals (keySelector)) {
				this.element_selector = elementSelector;
				this.element_block = elementBlock;
			}
		}

 private bool AreTheSame(Expression first, Expression second)
 {
     //those expressions' properties should point to the same objects, however the expressions themselves might not be the same object
     if (first.CodeNodeType != second.CodeNodeType)
     {
         return false;
     }
     return first.Equals(second);
 }

		protected bool CompareTargets(Expression assignee, Expression target)
		{
			if (target == null || assignee == null || target.CodeNodeType != assignee.CodeNodeType)
			{
				return false;
			}

			switch (target.CodeNodeType)
			{
				case CodeNodeType.PropertyReferenceExpression:
					var propertyReference = target as PropertyReferenceExpression;
					var assigneeProperty = assignee as PropertyReferenceExpression;

					if (!propertyReference.Property.Equals(assigneeProperty.Property))
					{
						return false;
					}

					return CompareTargets(assigneeProperty.Target, propertyReference.Target);

				default:
					return target.Equals(assignee);
			}
		}

		bool CheckEqualAssign (Expression t)
		{
			if (source is Assign) {
				Assign a = (Assign) source;
				if (t.Equals (a.Target))
					return true;
				return a is SimpleAssign && ((SimpleAssign) a).CheckEqualAssign (t);
			}
			return t.Equals (source);
		}

 /// <summary>
 /// Decides if two expressions have the same semantics.
 /// </summary>
 /// <param name="first"> The first expression.</param>
 /// <param name="second">The second expression.</param>
 /// <returns>Returns true if the expressions have the same semantics.</returns>
 private bool AreEqual(Expression first, Expression second)
 {
     return first.Equals(second);
 }