/// <summary>
/// 合并外键
/// </summary>
public void AddNavMembers(HashCollection <NavMember> navMembers)
{
if (navMembers != null && navMembers.Count > 0)
{
foreach (var nav in navMembers)
{
if (!_navMembers.Contains(nav.KeyId))
{
_navMembers.Add(nav);
}
}
}
}
/// <summary>
/// 访问导航属性
/// </summary>
/// <param name="expression">导航属性表达式</param>
/// <param name="memberName">成员名称</param>
/// <returns></returns>
protected virtual string VisitNavMember(Expression expression, string memberName = null)
{
// 表达式 => b.Client.Address.AddressName
Expression node = expression;
Stack <NavMember> stack = null;
string alias = string.Empty;
while (node != null && node.Visitable())
{
if (node.NodeType != ExpressionType.MemberAccess)
{
break;
}
if (stack == null)
{
stack = new Stack <NavMember>();
}
var member = node as MemberExpression;
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(member.Expression.Type);
ForeignKeyAttribute attribute = typeRuntime.GetMemberAttribute <ForeignKeyAttribute>(member.Member.Name);
if (attribute == null)
{
break;
}
string key = member.GetKeyWidthoutAnonymous();
stack.Push(new NavMember(key, member));
node = member.Expression;
if (node.NodeType == ExpressionType.Call)
{
node = (node as MethodCallExpression).Object;
}
}
if (stack != null && stack.Count > 0)
{
while (stack != null && stack.Count > 0)
{
NavMember nav = stack.Pop();
Type type = nav.Expression.Type;
if (type.IsGenericType)
{
type = type.GetGenericArguments()[0];
}
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(type);
// 检查表达式是否由 GetTable<,>(path) 显式指定过别名
alias = _aliases.GetGetTableAlias(nav.KeyId);
if (string.IsNullOrEmpty(alias))
{
// 如果没有，检查查询表达式是否显示指定该表关联
alias = _aliases.GetJoinTableAlias(typeRuntime.TableName);
}
if (string.IsNullOrEmpty(alias))
{
// 如果没有，则使用导航属性别名
alias = _aliases.GetNavTableAlias(nav.KeyId);
if (!_navMembers.Contains(nav.KeyId))
{
_navMembers.Add(nav);
}
}
// 例： a.Client.ClientId
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
alias = _aliases.GetTableAlias(expression);
_builder.AppendMember(alias, memberName);
}
// Fix issue# Join 表达式显式指定导航属性时时，alias 为空
return(alias);
}