public static Expression <Func <TDto, bool> > GetQueryableFilterExpr <TDto>(this IResolverContext context)
{
Expression <Func <TDto, bool> > filter = null;
if (context.Field?.Arguments["where"]?.Type is InputObjectType whereIot &&
whereIot is IFilterInputType whereFit)
{
var whereValueNode = context.Argument <IValueNode>("where");
if (whereValueNode != null)
{
var queryableFilterVisitor = new QueryableFilterVisitor(
whereIot,
whereFit.EntityType,
TypeConversion.Default);
if (whereValueNode.Kind != NodeKind.NullValue)
{
whereValueNode.Accept(queryableFilterVisitor);
filter = queryableFilterVisitor?.CreateFilter <TDto>();
}
}
}
return(filter);
}
public Expression HandleLeave(
SelectionVisitorContext context,
IFieldSelection selection,
Expression expression)
{
if (context.TryGetValueNode("where", out IValueNode filter) &&
selection.Field.Arguments["where"].Type is InputObjectType iot &&
iot is IFilterInputType fit)
{
var visitor = new QueryableFilterVisitor(
iot, fit.EntityType, context.Conversion);
filter.Accept(visitor);
return(Expression.Call(
typeof(Enumerable),
"Where",
new[] { fit.EntityType },
expression,
visitor.CreateFilter()));
}
return(expression);
}
