// => new App() {Id = p.Id}}
protected override Expression VisitMemberInit(MemberInitExpression node)
{
// 如果有一对多的导航属性会产生嵌套的SQL，这时需要强制主表选择的列里面必须包含导航外键
// TODO #对 Bindings 进行排序，保证导航属性的赋值一定要最后面#
// 未实现，在书写表达式时人工保证 ##
if (node.NewExpression != null)
{
this.VisitNewImpl(node.NewExpression);
}
if (_navChainHopper.Count == 0)
{
_navChainHopper.Add(node.Type.Name);
}
for (int i = 0; i < node.Bindings.Count; i++)
{
MemberAssignment binding = node.Bindings[i] as MemberAssignment;
if (binding == null)
{
throw new XFrameworkException("Only 'MemberAssignment' binding supported.");
}
Type propertyType = (node.Bindings[i].Member as System.Reflection.PropertyInfo).PropertyType;
bool isNavigation = !TypeUtils.IsPrimitiveType(propertyType);
#region 一般属性
// 非导航属性
if (!isNavigation)
{
if (binding.Expression.CanEvaluate())
{
_builder.Append(binding.Expression.Evaluate().Value, binding.Member, node.Type);
}
else
{
this.VisitWithoutRemark(x => this.VisitMemberBinding(binding));
}
// 选择字段
this.AddPickColumn(binding.Member.Name);
}
#endregion 一般属性
#region 导航属性
else
{
// 非显式指定的导航属性需要有 ForeignKeyAttribute
if (binding.Expression.NodeType == ExpressionType.MemberAccess && binding.Expression.Acceptable())
{
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(binding.Member.DeclaringType);
var attribute = typeRuntime.GetInvokerAttribute <ForeignKeyAttribute>(binding.Member.Name);
if (attribute == null)
{
throw new XFrameworkException("Complex property {{{0}}} must mark 'ForeignKeyAttribute' ", binding.Member.Name);
}
}
// 生成导航属性描述集合，以类名.属性名做为键值
int n = _navChainHopper.Count;
string keyName = _navChainHopper.Count > 0 ? _navChainHopper[_navChainHopper.Count - 1] : string.Empty;
keyName = !string.IsNullOrEmpty(keyName) ? keyName + "." + binding.Member.Name : binding.Member.Name;
var nav = new Navigation(keyName, binding.Member);
if (!_navigations.Contains(keyName))
{
// fix issue# spliton 列占一个位
nav.StartIndex = _pickColumns.Count;
nav.FieldCount = GetFieldCount(binding.Expression) + (binding.Expression.NodeType == ExpressionType.MemberAccess && binding.Expression.Acceptable() ? 1 : 0);
_navigations.Add(keyName, nav);
_navChainHopper.Add(keyName);
}
// 1.不显式指定导航属性，例：a.Client.ClientList
// 2.表达式里显式指定导航属性，例：b
if (binding.Expression.NodeType == ExpressionType.MemberAccess)
{
this.VisitNavigation(binding.Expression as MemberExpression, binding.Expression.Acceptable());
}
else if (binding.Expression.NodeType == ExpressionType.New)
{
this.VisitNewImpl(binding.Expression as NewExpression);
}
else if (binding.Expression.NodeType == ExpressionType.MemberInit)
{
this.VisitMemberInit(binding.Expression as MemberInitExpression);
}
// 恢复访问链
// 在访问导航属性时可能是 Client.CloudServer，这时要恢复为 Client，以保证能访问 Client 的下一个导航属性
if (_navChainHopper.Count != n)
{
_navChainHopper.RemoveAt(_navChainHopper.Count - 1);
}
}
#endregion 导航属性
}
return(node);
}
