/// <summary>
/// 判断属性访问表达式是否有系统动态生成前缀
/// <code>
/// h__TransparentIdentifier.a.CompanyName
/// </code>
/// </summary>
public static bool IsAnonymous(this Expression node)
{
// <>h__TransparentIdentifier => h__TransparentIdentifier.a.CompanyName
Expression exp = node;
ParameterExpression paramExp = exp.NodeType == ExpressionType.Lambda
? (node as LambdaExpression).Parameters[0]
: exp as ParameterExpression;
if (paramExp != null)
{
return(ExpressionExtensions._isAnonymous(paramExp.Name));
}
if (exp.NodeType == ExpressionType.MemberAccess) // <>h__TransparentIdentifier.a.CompanyName
{
MemberExpression memExp = exp as MemberExpression;
if (ExpressionExtensions._isAnonymous(memExp.Member.Name))
{
return(true);
}
return(ExpressionExtensions.IsAnonymous(memExp.Expression));
}
return(false);
}
/// <summary>
/// 在递归访问 MemberAccess 表达式时，判定节点是否能够被继续递归访问
/// </summary>
public static bool IsVisitable(this Expression node)
{
// a
// <>h__TransparentIdentifier.a
// <>h__TransparentIdentifier0.<>h__TransparentIdentifier1.a
if (node.NodeType == ExpressionType.Parameter)
{
return(false);
}
if (node.NodeType == ExpressionType.MemberAccess)
{
MemberExpression m = node as MemberExpression;
if (m.Expression.NodeType == ExpressionType.Parameter)
{
string name = (m.Expression as ParameterExpression).Name;
if (ExpressionExtensions._isAnonymous(name))
{
return(false);
}
}
if (m.Expression.NodeType == ExpressionType.MemberAccess)
{
string name = (m.Expression as MemberExpression).Member.Name;
if (ExpressionExtensions._isAnonymous(name))
{
return(false);
}
}
}
return(true);
}
/// <summary>
/// 判断是否是分组表达式
/// </summary>
public static bool IsGrouping(this Expression node)
{
//g.Key
//g.Key.CompanyName
//g.Max()
//g=>g.xxx
//g.Key.CompanyId.Length
//g.Key.Length
// g | g=>g.xx
Expression exp = node;
ParameterExpression paramExp = exp.NodeType == ExpressionType.Lambda
? (node as LambdaExpression).Parameters[0]
: exp as ParameterExpression;
if (paramExp != null)
{
return(ExpressionExtensions._isGrouping(paramExp.Type.Name));
}
// g.Max
MethodCallExpression callExp = exp as MethodCallExpression;
if (callExp != null)
{
return(ExpressionExtensions._isGrouping(callExp.Arguments[0].Type.Name));
}
MemberExpression memExp = exp as MemberExpression;
if (memExp != null)
{
// g.Key
var g1 = memExp.Member.Name == "Key" && ExpressionExtensions._isGrouping(memExp.Expression.Type.Name);
if (g1)
{
return(g1);
}
// g.Key.Length | g.Key.Company | g.Key.CompanyId.Length
memExp = memExp.Expression as MemberExpression;
if (memExp != null)
{
g1 = memExp.Member.Name == "Key" && ExpressionExtensions._isGrouping(memExp.Expression.Type.Name) && memExp.Type.Namespace == null; //匿名类没有命令空间
if (g1)
{
return(g1);
}
}
}
return(false);
}
