private Expression VisitMember_Navigation(MemberExpression node)
{
string alias = string.Empty;
Type type = node.Type;
if (node.IsVisitable())
{
int index = 0;
this.VisitNavigation(node);
foreach (var kvp in Navigations)
{
index += 1;
if (index < Navigations.Count)
{
continue;
}
alias = _aliases.GetNavigationTableAlias(kvp.Key);
type = kvp.Value.Type;
}
}
else
{
alias = _aliases.GetTableAlias(node);
type = node.Type;
}
//未实现 1对多 映射
//if (type.IsGenericType) type = type.GetGenericArguments()[0];
this.VisitAllMember(type, alias);
return(node);
}
protected virtual void VisitNavigation(Expression node, string memberName = null)
{
// 表达式 => b.Client.Address.AddressName
Expression f = node;
Stack <KeyValuePair <string, MemberExpression> > stack = null;
while (f != null && f.IsVisitable())
{
if (f.NodeType != ExpressionType.MemberAccess)
{
break;
}
if (stack == null)
{
stack = new Stack <KeyValuePair <string, MemberExpression> >();
}
MemberExpression m = f as MemberExpression;
var runtime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Expression.Type);
ForeignKeyAttribute attribute = runtime.GetWrapperAttribute <ForeignKeyAttribute>(m.Member.Name);
if (attribute == null)
{
break;
}
string key = m.GetKeyWidthoutAnonymous();
stack.Push(new KeyValuePair <string, MemberExpression>(key, m));
f = m.Expression;
}
if (stack != null && stack.Count > 0)
{
while (stack != null && stack.Count > 0)
{
KeyValuePair <string, MemberExpression> kvp = stack.Pop();
string key = kvp.Key;
MemberExpression m = kvp.Value;
var runtime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Type);
// 检查查询表达式是否显示指定该表关联
string alias = _aliases.GetJoinTableAlias(runtime.TableName);
if (string.IsNullOrEmpty(alias))
{
// 如果没有，则使用导航属性别名
alias = _aliases.GetNavigationTableAlias(key);
if (!_navigations.ContainsKey(kvp.Key))
{
_navigations.Add(kvp);
}
}
if (stack.Count == 0 && !string.IsNullOrEmpty(memberName))
{
_builder.AppendMember(alias, memberName);
}
}
}
else
{
// => SelectMany 也会产生类似 'b.Client.Address.AddressName' 这样的表达式
string alias = _aliases.GetTableAlias(node);
_builder.AppendMember(alias, memberName);
}
//return f;
}
