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; }
// 添加导航属性关联 protected virtual void AppendNavigation() { if (this.AdditionForeigns == null || this.AdditionForeigns.Count == 0) { return; } //开始产生LEFT JOIN 子句 SqlBuilder builder = this.JoinFragment; foreach (var kvp in _navigations) { string key = kvp.Key; MemberExpression m = kvp.Value; var runtime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Expression.Type); ForeignKeyAttribute attribute = runtime.GetWrapperAttribute <ForeignKeyAttribute>(m.Member.Name); string innerKey = string.Empty; string outerKey = key; string innerAlias = string.Empty; if (!m.Expression.IsVisitable()) { innerKey = m.Expression.NodeType == ExpressionType.Parameter ? (m.Expression as ParameterExpression).Name : (m.Expression as MemberExpression).Member.Name; } else { MemberExpression mLeft = m.Expression as MemberExpression; string name = TypeRuntimeInfoCache.GetRuntimeInfo(mLeft.Type).TableName; innerAlias = _aliases.GetJoinTableAlias(name); if (string.IsNullOrEmpty(innerAlias)) { string keyLeft = mLeft.GetKeyWidthoutAnonymous(); if (_navigations.ContainsKey(keyLeft)) { innerKey = keyLeft; } } } string alias1 = !string.IsNullOrEmpty(innerAlias) ? innerAlias : _aliases.GetTableAlias(innerKey); string alias2 = _aliases.GetTableAlias(outerKey); builder.AppendNewLine(); builder.Append("LEFT JOIN "); Type pType = m.Type; //不实现一对多映射 //if (pType.IsGenericType) pType = pType.GetGenericArguments()[0]; builder.AppendMember(TypeRuntimeInfoCache.GetRuntimeInfo(pType).TableName); builder.Append(" "); builder.Append(alias2); builder.Append(" ON "); for (int i = 0; i < attribute.InnerKeys.Length; i++) { builder.Append(alias1); builder.Append('.'); builder.AppendMember(attribute.InnerKeys[i]); builder.Append(" = "); builder.Append(alias2); builder.Append('.'); builder.AppendMember(attribute.OuterKeys[i]); if (i < attribute.InnerKeys.Length - 1) { builder.Append(" AND "); } } } }