private void VisitJoinSelector(Expression joinSelector, string outerTypeName, string innerTypeName, FetchLinkEntity link)
{
UnaryExpression uexp = joinSelector as UnaryExpression;
LambdaExpression lxp = (uexp.Operand as LambdaExpression);
NewExpression nxp = lxp.Body as NewExpression;
//if(nxp.Arguments[0].NodeType == ExpressionType.
foreach (Expression exp in nxp.Arguments)
{
string entName;
// the format of the selector depends on the presence of a where clause it seems
if (exp is MemberExpression)
{
MemberExpression masgn = exp as MemberExpression;
entName = (masgn.Expression as ParameterExpression).Type.Name;
if (entName == outerTypeName) // add to outer attributes
stmt.Entity.Columns.Columns.Add(masgn.Member.Name);
else if (entName == innerTypeName) // add to link-entity columns
link.Columns.Columns.Add(masgn.Member.Name);
}
else if (exp is ParameterExpression)
{
ParameterExpression pExp = exp as ParameterExpression;
entName = pExp.Type.Name;
if (entName == innerTypeName)
// record the alias and link-node for future use
attributeMap.Add(pExp.Name, link);
//if(entName == outerTypeName)
// do nothing, this will be handled by the regular selector
}
else
{
throw new Exception("Unknown Expression type when visiting join-selector");
}
}
}
private void VisitJoin(MethodCallExpression join)
{
// this will set up the correct Fetchentity
this.Visit(join.Arguments[0]);
FetchLinkEntity link;
// TODO: Handle non-dotted values
MemberExpression outerMemberExp = (((join.Arguments[2] as UnaryExpression).Operand as LambdaExpression).Body as MemberExpression).Expression as MemberExpression;
MemberExpression innerMemberExp = (((join.Arguments[3] as UnaryExpression).Operand as LambdaExpression).Body as MemberExpression).Expression as MemberExpression;
string outerTypeName = outerMemberExp.Expression.Type.Name;
string innerTypeName = innerMemberExp.Expression.Type.Name;
// This was commented out to allow intra-table joins - wonder why I put it in?
//if (!innerTypeName.Equals(stmt.Entity.EntityName))
//{
link = new FetchLinkEntity(innerTypeName);
link.From = innerMemberExp.Member.Name;
link.To = outerMemberExp.Member.Name;
//}
//else
// throw new ArgumentException();
link.Columns = new FetchColumnSet();
link.Columns.Columns = new System.Collections.Specialized.StringCollection();
// TODO: this is very bad karma, but I'm too tired now
link.Alias = "";
stmt.Entity.LinkEntities.Add(link);
// now get the attributes
VisitJoinSelector(join.Arguments[4], outerTypeName, innerTypeName, link);
}