protected override ScalarExpression OnBuildQuery(QueryBuilderContext context)
{
if (ResultType.IsList)
{
throw new InvalidOperationException();
}
var result = new LiteralExpression
{
Value = TypedValueHelper.FromDataType(ResultType.Type, Value)
};
return(result);
}
/// <summary>
/// Returns a tree node that is representative of an entity or.
/// </summary>
/// <param name="context">Context information about this query building session, including the target structured query object.</param>
/// <param name="allowReuse">A dedicated node should be returned because the caller intends on disturbing it.</param>
/// <returns>A query node that can be used within the query.</returns>
public override SQ.Entity OnBuildQueryNode(QueryBuilderContext context, bool allowReuse)
{
IEntity instance = Instance.Entity;
long typeId = instance.TypeIds.First( );
if (context.ParentNode == null)
{
throw new Exception("No context.");
}
// Look for an existing relationship node in the tree that we can reuse
SQ.CustomJoinNode result = !allowReuse ? null :
context.ParentNode
.RelatedEntities
.OfType <SQ.CustomJoinNode>( )
.FirstOrDefault(cj => IsMatch(cj, Instance.Id) && cj.EntityTypeId.Id == typeId);
// New node
if (result == null)
{
result = new SQ.CustomJoinNode
{
EntityTypeId = typeId,
JoinPredicateScript = "true"
};
SQ.ScalarExpression predicate = new SQ.ComparisonExpression
{
Operator = SQ.ComparisonOperator.Equal,
Expressions =
{
new SQ.IdExpression
{
NodeId = result.NodeId
},
new SQ.LiteralExpression
{
Value = TypedValueHelper.FromDataType(ResultType.Type, Instance.Id)
}
}
};
result.Conditions = new List <SQ.ScalarExpression> {
predicate
};
}
context.ParentNode.RelatedEntities.Add(result);
AddChildNodes(context, result, allowReuse);
return(result);
}