Reputation: 12910
In this query, I always want the 'normal' type element.
If the _includeX flag is set, I want the 'workspace' type elements, too.
Is there a way to write this as one query? Or build the where clause based on _includeX before submitting the query?
if (_includeX) {
query = from xElem in doc.Descendants(_xString)
let typeAttributeValue = xElem.Attribute(_typeAttributeName).Value
where typeAttributeValue == _sWorkspace ||
typeAttributeValue == _sNormal
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
}
else {
query = from xElem in doc.Descendants(_xString)
where xElem.Attribute(_typeAttributeName).Value == _sNormal
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
}
Upvotes: 1
Views: 908
Reputation: 61903
You can break it into a separate predicate:
Predicate<string> selector = x=> _includeX
? x == _sWorkspace || x == _sNormal
: x == _sNormal;
query = from xElem in doc.Descendants(_xString)
where selector(xElem.Attribute(_typeAttributeName).Value)
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
Or inline the condition:
query = from xElem in doc.Descendants(_xString)
let typeAttributeValue = xElem.Attribute(_typeAttributeName).Value
where (typeAttributeValue == _sWorkspace && _includeX) ||
typeAttributeValue == _sNormal
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};
Or remove query expression usage and do it this way:-
var all = doc.Descendants(_xString);
var query = all.Where( xElem=> {
var typeAttributeValue = xElem.Attribute(_typeAttributeName).Value;
return typeAttributeValue == _sWorkspace && includeX ) || typeAttributeValue == _sNormal;
})
.Select( xElem =>
select new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
})
Or combine the first and third and do:
Predicate<string> selector = x=> _includeX
? x == _sWorkspace || x == _sNormal
: x == _sNormal;
query = doc.Descendants(_xString)
.Where(xElem => selector(xElem.Attribute(_typeAttributeName).Value))
.Select(xElem => new xmlThing
{
_location = xElem.Attribute(_nameAttributeName).Value,
_type = xElem.Attribute(_typeAttributeName).Value,
};)
It all depends what's going to work cleanest in your context.
Do yourself a favour and buy (and read!) C# in Depth and it'll all make sense a lot more quickly that learning this stuff bit by bit...
Upvotes: 1