// 遍历 Include 包含的导航属性
private void VisitInclude()
{
if (_includes == null || _includes.Count == 0)
{
return;
}
foreach (var dbExpression in _includes)
{
Expression navExpression = dbExpression.Expressions[0];
Expression pickExpression = dbExpression.Expressions.Length > 1 ? dbExpression.Expressions[1] : null;
Expression predicateExpression = dbExpression.Expressions.Length > 2 ? dbExpression.Expressions[2] : null;
if (navExpression == null)
{
continue;
}
if (navExpression.NodeType == ExpressionType.Lambda)
{
navExpression = (navExpression as LambdaExpression).Body;
}
var memberExpression = navExpression as MemberExpression;
if (memberExpression == null)
{
throw new XFrameworkException("Include expression body must be 'MemberExpression'.");
}
// 例：Include(a => a.Client.AccountList[0].Client)
// 解析导航属性链
List <Expression> navStack = new List <Expression>();
while (memberExpression != null)
{
// a.Client 要求 <Client> 必须标明 ForeignKeyAttribute
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(memberExpression.Expression.Type);
var attribute = typeRuntime.GetMemberAttribute <ForeignKeyAttribute>(memberExpression.Member.Name);
if (attribute == null)
{
throw new XFrameworkException("ForeignKeyAttribute not found for include member {0}.{1}", typeRuntime.Type.Name, memberExpression.Member.Name);
}
MemberExpression m = null;
navStack.Add(memberExpression);
if (memberExpression.Expression.NodeType == ExpressionType.MemberAccess)
{
m = (MemberExpression)memberExpression.Expression;
}
else if (memberExpression.Expression.NodeType == ExpressionType.Call)
{
m = (memberExpression.Expression as MethodCallExpression).Object as MemberExpression;
}
//var m = memberExpression.Expression as MemberExpression;
if (m == null)
{
navStack.Add(memberExpression.Expression);
}
memberExpression = m;
}
// 生成导航属性描述信息
string keyId = string.Empty;
for (int index = navStack.Count - 1; index >= 0; index--)
{
Expression expression = navStack[index];
memberExpression = expression as MemberExpression;
if (memberExpression == null)
{
continue;
}
if (_navDescriptors == null)
{
_navDescriptors = new NavDescriptorCollection();
}
keyId = memberExpression.GetKeyWidthoutAnonymous(true);
if (!_navDescriptors.Contains(keyId))
{
// Fix issue# SplitOn 列占一个位
var nav = new NavDescriptor(keyId, memberExpression.Member);
nav.StartIndex = index == 0 ? _selectedColumns.Count : -1;
nav.FieldCount = index == 0 ? (GetFieldCount(pickExpression == null ? navExpression : pickExpression) + 1) : -1;
_navDescriptors.Add(nav);
}
}
this.VisitNavigation(memberExpression, true, pickExpression, predicateExpression);
}
}
// => Name = "Name"
private void VisitMemberAssignmentImpl(Type newType, MemberAssignment m)
{
// 先添加当前字段的访问痕迹标记
_visitedStack.Add(m.Member, newType);
if (TypeUtils.IsPrimitive(m.Member))
{
this.VisitMemberBinding(m);
// 选择字段
this.AddSelectedColumn(m.Member, newType);
}
else
{
// 非显式指定的导航属性需要有 ForeignKeyAttribute
if (m.Expression.NodeType == ExpressionType.MemberAccess && m.Expression.Visitable())
{
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(newType);
var attribute = typeRuntime.GetMemberAttribute <ForeignKeyAttribute>(m.Member.Name);
// 不能当做导航属性的复杂字段
if (attribute == null)
{
return;
}
}
// 生成导航属性描述集合，以类名.属性名做为键值
if (_navDescriptorKeys == null)
{
_navDescriptorKeys = new List <string>();
}
if (_navDescriptors == null)
{
_navDescriptors = new NavDescriptorCollection();
}
int num = _navDescriptorKeys.Count;
string keyId = _navDescriptorKeys.Count > 0 ? _navDescriptorKeys[_navDescriptorKeys.Count - 1] : string.Empty;
keyId = !string.IsNullOrEmpty(keyId) ? keyId + "." + m.Member.Name : m.Member.Name;
var nav = new NavDescriptor(keyId, m.Member);
if (!_navDescriptors.Contains(keyId))
{
// Fix issue# spliton 列占一个位
nav.StartIndex = _selectedColumns.Count;
nav.FieldCount = GetFieldCount(m.Expression) + (m.Expression.NodeType == ExpressionType.MemberAccess && m.Expression.Visitable() ? 1 : 0);
_navDescriptors.Add(nav);
_navDescriptorKeys.Add(keyId);
}
// 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 (m.Expression.NodeType == ExpressionType.MemberAccess)
{
this.VisitNavigation(m.Expression as MemberExpression, m.Expression.Visitable());
}
else if (m.Expression.NodeType == ExpressionType.New)
{
this.VisitNewImpl(m.Expression as NewExpression, false);
}
else if (m.Expression.NodeType == ExpressionType.MemberInit)
{
this.VisitMemberInit(m.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 (_navDescriptorKeys.Count != num)
{
_navDescriptorKeys.RemoveAt(_navDescriptorKeys.Count - 1);
}
}
}