/// <summary>
/// Visit the children of <see cref="T:System.Linq.Expressions.MemberExpression" />.
/// </summary>
/// <param name="node">Expression to visit.</param>
/// <returns>
/// Altered expression, if it or any subexpression was modified; otherwise, returns the original expression.
/// </returns>
protected override Expression VisitMember(MemberExpression node)
{
var expr = Visit(node.Expression);
if (expr != null && expr.Type != node.Type)
{
if (mapper == null)
{
mapper = Mapper.GetMapper(node.Member.DeclaringType, destinationType);
}
Expression expDest = null;
// We consider that the primitive class is the simple property(not a sub's object).
if (!expr.Type.IsValueType && expr.Type != typeof(string) &&
expr.NodeType != ExpressionType.Parameter && expr.NodeType != ExpressionType.Constant)
{
var subExp = Mapper.GetMapper(node.Member.DeclaringType, expr.Type);
expDest = subExp.GetLambdaDest(node.Member.Name);
return(AnalyseDestExpression(expr, expDest));
}
else
{
expDest = mapper.GetLambdaDest(node.Member.Name);
if (expDest != null)
{
return(AnalyseDestExpression(expr, expDest));
}
}
}
return(base.VisitMember(node));
}
/// <summary>
/// 访问子表达式树
/// </summary>
/// <param name="node">访问表达式树</param>
/// <returns>
/// 改变表达式，如果它或它的任何子表达式被修改; 否则，返回原始表达式。
/// </returns>
protected override Expression VisitMember(MemberExpression node)
{
var expr = Visit(node.Expression);
if (expr != null && expr.Type != node.Type)
{
if (_mapper == null)
{
_mapper = ExpressionMapper.GetMapper(node.Member.DeclaringType, _destinationType);
}
Expression expDest;
// 认为原始类是简单属性（不是子对象）。
if (!expr.Type.IsValueType && expr.Type != typeof(string) && expr.NodeType != ExpressionType.Parameter && expr.NodeType != ExpressionType.Constant)
{
var subExp = ExpressionMapper.GetMapper(node.Member.DeclaringType, expr.Type);
expDest = subExp.GetLambdaDest(node.Member.Name);
return(AnalyseDestExpression(expr, expDest));
}
expDest = _mapper.GetLambdaDest(node.Member.Name);
if (expDest != null)
{
return(AnalyseDestExpression(expr, expDest));
}
}
return(base.VisitMember(node));
}