static ISqlPredicate MakeIsPredicate(ExpressionBuilder builder, IBuildContext context, Type fromType, Type toType)
{
var table = new SqlTable(builder.MappingSchema, fromType);
var mapper = builder.MappingSchema.GetEntityDescriptor(fromType);
var discriminators = mapper.InheritanceMapping;
return(builder.MakeIsPredicate(context, discriminators, toType,
name =>
{
var field = table.Fields.Values.First(f => f.Name == name);
var member = field.ColumnDescriptor.MemberInfo;
var expr = Expression.MakeMemberAccess(Expression.Parameter(member.DeclaringType, "p"), member);
var sql = context.ConvertToSql(expr, 1, ConvertFlags.Field)[0].Sql;
return sql;
}));
}
protected override IBuildContext BuildMethodCall(ExpressionBuilder builder, MethodCallExpression methodCall, BuildInfo buildInfo)
{
var sequence = builder.BuildSequence(new BuildInfo(buildInfo, methodCall.Arguments[0]));
var table = sequence as TableBuilder.TableContext;
if (table != null && table.InheritanceMapping.Count > 0)
{
var objectType = methodCall.Type.GetGenericArgumentsEx()[0];
if (table.ObjectType.IsSameOrParentOf(objectType))
{
var predicate = builder.MakeIsPredicate(table, objectType);
if (predicate.GetType() != typeof(SelectQuery.Predicate.Expr))
{
sequence.SelectQuery.Where.SearchCondition.Conditions.Add(new SelectQuery.Condition(false, predicate));
}
}
}
else
{
var toType = methodCall.Type.GetGenericArgumentsEx()[0];
var gargs = methodCall.Arguments[0].Type.GetGenericArguments(typeof(IQueryable <>));
var fromType = gargs == null ? typeof(object) : gargs[0];
if (toType.IsSubclassOfEx(fromType))
{
for (var type = toType.BaseTypeEx(); type != null && type != typeof(object); type = type.BaseTypeEx())
{
var mapping = builder.MappingSchema.GetEntityDescriptor(type).InheritanceMapping;
if (mapping.Count > 0)
{
var predicate = MakeIsPredicate(builder, sequence, fromType, toType);
sequence.SelectQuery.Where.SearchCondition.Conditions.Add(new SelectQuery.Condition(false, predicate));
return(new OfTypeContext(sequence, methodCall));
}
}
}
}
return(sequence);
}