// Client = a.Client.CloudServer
private Expression VisitNavigation(MemberExpression node, bool visitNavigation)
{
string alias = string.Empty;
Type type = node.Type;
if (node.Acceptable())
{
// 例： Client = a.Client.CloudServer
// fix issue# Join 表达式显式指定导航属性时时，alias 为空
// fix issue# 多个导航属性时 AppendNullColumn 只解析当前表达式的
int index = 0;
int num = this.NavMembers != null ? this.NavMembers.Count : 0;
alias = this.VisitNavMember(node);
if (num != this.NavMembers.Count)
{
foreach (var kvp in NavMembers)
{
index += 1;
if (index < NavMembers.Count && index > num)
{
alias = _aliases.GetNavigationTableAlias(kvp.Key);
//navKey = kvp.Key;
//if (visitNavigation) AppendNullColumn(kvp.Value.Member, alias, navKey);
continue;
}
//navKey = kvp.Key;
alias = _aliases.GetNavigationTableAlias(kvp.Key);
type = kvp.Value.Type;
}
}
else
{
}
}
else
{
// 例： Client = b
alias = _aliases.GetTableAlias(node);
type = node.Type;
}
if (type.IsGenericType)
{
type = type.GetGenericArguments()[0];
}
this.VisitAllMember(type, alias);
if (visitNavigation)
{
AppendNullColumn(node.Member, alias);
}
return(node);
}
// 访问导航属性
protected virtual string VisitNavMember(Expression expression, string memberName = null)
{
// 表达式 => b.Client.Address.AddressName
Expression node = expression;
Stack <KeyValuePair <string, MemberExpression> > stack = null;
string alias = string.Empty;
while (node != null && node.Acceptable())
{
if (node.NodeType != ExpressionType.MemberAccess)
{
break;
}
if (stack == null)
{
stack = new Stack <KeyValuePair <string, MemberExpression> >();
}
MemberExpression memberExpression = node as MemberExpression;
TypeRuntimeInfo typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(memberExpression.Expression.Type);
ForeignKeyAttribute attribute = typeRuntime.GetInvokerAttribute <ForeignKeyAttribute>(memberExpression.Member.Name);
if (attribute == null)
{
break;
}
string key = memberExpression.GetKeyWidthoutAnonymous();
stack.Push(new KeyValuePair <string, MemberExpression>(key, memberExpression));
node = memberExpression.Expression;
if (node.NodeType == ExpressionType.Call)
{
node = (node as MethodCallExpression).Object;
}
}
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;
Type type = m.Type;
if (type.IsGenericType)
{
type = type.GetGenericArguments()[0];
}
TypeRuntimeInfo typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(type);
// 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.GetNavigationTableAlias(key);
if (!_navMembers.ContainsKey(kvp.Key))
{
_navMembers.Add(kvp);
}
}
// 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);
}