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How to perform inner sort of an List<> in object?

I am trying to wrap my head around this, but can't think of any good way to do it. I have an object, for which the properties are one certain class (Though could contain multiple Classes, Lists etc.). These might be null or empty. An example of the structure can be seen below. So here I would have some string data, objects, List and even in the List a list object.
The goal is to get matched results from actual and Expected
{
"Name":"First Name",
"LastName":"Yeah",
"FavourityBooks":[
{
"BookName":"Hamlet",
"Printed":"Outside USA",
"PriceInDollars":100
},
{
"BookName": "Romeo And the Girl",
"Printed":"Somewhere In USA",
"PriceInDollars":99
}
],
"Debt":[
{
"c":[
{
"FriendName":"August",
"Amount":47
},
{
"FriendName":"April",
"Amount":53
}
],
"Sum":100
},
{
"ToBanks":[
{
"BankName":"Scotland BAnk",
"Amount":150
},
{
"BankName":"Some Other Bank",
"Amount":150
}
],
"Sum":300
}
]
}
One Way to go Sort Easily the Object by all properties
These results are coming from Graph Ql, but development has not implemented a sorting method as far as I was told.
How could I sort The inner list of FavourityBooks, by all three properties?
How could I sort The inner list of ToBanks or ToBanks and sort the list which they are in as well?
I don't know if I can achieve this by hardcoding each of the list sorting separately. some kind of recursive function should be used in order to sort each child object by all of its properties.
This though seems a very complex task to me. Any ideas?
Second Way to go is on the comparison level, more preferable
The way how I was thinking to do is maybe can sort these objects on the comparison, not prior, though I am lacking the ideas, how to sort them in this area as well.
E.g. A method:
public static List<EqualObjects> CompareObjects(object baseObject, object compareObject, object baseParentObject, object secondParentObject)
{
object basePropertyValue = null;
object secondPropertyValue = null;
var result = new List<EqualObjects>();
var baseObjectType = baseObject.GetType();
var secondObjectType = compareObject.GetType();
var baseObjectProperties = baseObjectType.GetProperties();
var secondObjectProperties = secondObjectType.GetProperties();
foreach (var baseProperty in baseObjectProperties)
{
var compareProperty = secondObjectProperties.FirstOrDefault(x => x.Name == baseProperty.Name);
//This gets the Object typeof(baseProperty) with the values
secondPropertyValue = compareProperty.GetValue(compareObject, null);
basePropertyValue = baseProperty.GetValue(baseObject, null);
var test = baseProperty.GetType().ToString();
if (basePropertyValue is null)
continue;
if (!baseProperty.PropertyType.FullName.Contains("System"))
{
result.AddRange(CompareObjects(basePropertyValue, secondPropertyValue, baseObject, compareObject));
continue;
}
if (baseProperty.PropertyType.FullName == "System.String")
{
result.AddRange(CompareSimpleElement(basePropertyValue, secondPropertyValue, baseObject, compareObject, baseProperty));
continue;
}
if (baseProperty.PropertyType.FullName == "System.Int32")
{
result.AddRange(CompareSimpleElement(basePropertyValue, secondPropertyValue, baseObject, compareObject, baseProperty));
continue;
}
if (baseProperty.PropertyType.FullName == "System.Decimal")
{
result.AddRange(CompareSimpleElement(basePropertyValue, secondPropertyValue, baseObject, compareObject, baseProperty));
continue;
}
//System.Collections.Generic.List
if (baseProperty.PropertyType.FullName.Contains("System.Collections.Generic.List") && baseProperty.PropertyType.FullName.Contains("System.String"))
{
var baseCollection = (List<string>)basePropertyValue;
var compareCollection = (List<string>)secondPropertyValue;
for (var i = 0; i < baseCollection.Count; i++)
{
if (baseCollection[i].Length > 0 && compareCollection[i].Length > 0)
{
result.AddRange(CompareSimpleList(baseCollection[i], compareCollection[i], baseObject,
compareObject, baseProperty,i));
}
}
}
if (baseProperty.PropertyType.FullName.Contains("System.Collections.Generic.List"))
{
var baseCollection = (List<object>)basePropertyValue;
var compareCollection = (List<object>)secondPropertyValue;
for (var i = 0; i < baseCollection.Count; i++)
{
}
}
}
return result;
}
Ideally, I could achieve this if I would be able to sort the BaseCollection and compareCollection by all properties (so if List, then sort by Object Properties) at first, then loop through and if another complex object would again sort it till it is a List which would always be the case once it gets here, other parts would be caught out previously.
if (baseProperty.PropertyType.FullName.Contains("System.Collections.Generic.List"))
{
var baseCollection = (List<object>)basePropertyValue;
var compareCollection = (List<object>)secondPropertyValue;
for (var i = 0; i < baseCollection.Count; i++)
{
}
}
Regards,

IEnumerable failed to set element

I have a ViewModel that contains different elements inside different tables that I tend to assign to it by query.
My problem is that I can't do this with IEnumerable (in GetAll() below), it keeps returning me null for RoomCode but for a single item (in GetDeviceId() below) then it works fine.
public IEnumerable<DeviceViewModel> GetAll()
{
var result = deviceRepository.GetAll().Select(x => x.ToViewModel<DeviceViewModel>());
for(int i = 0; i < result.Count(); i++)
{
int? deviceID = result.ElementAt(i).DeviceId;
result.ElementAt(i).RoomCode = deviceRepository.GetRoomCode(deviceID);
}
return result;
}
public DeviceViewModel GetDeviceID(int deviceID)
{
var result = new DeviceViewModel();
var device = deviceRepository.Find(deviceID);
if (device != null)
{
result = device.ToViewModel<DeviceViewModel>();
result.RoomCode = deviceRepository.GetRoomCode(deviceID);
}
else
{
throw new BaseException(ErrorMessages.DEVICE_LIST_EMPTY);
}
return result;
}
public string GetRoomCode(int? deviceID)
{
string roomCode;
var roomDevice = dbContext.Set<RoomDevice>().FirstOrDefault(x => x.DeviceId == deviceID && x.IsActive == true);
if (roomDevice != null)
{
var room = dbContext.Set<Room>().Find(roomDevice.RoomId);
roomCode = room.RoomCode;
}
else
{
roomCode = "";
}
return roomCode;
}

First, you need to materialize the query to a collection in local memory. Otherwise, the ElementAt(i) will query the db and give back some kind of temporary object each time it is used, discarding any change you do.
var result = deviceRepository.GetAll()
.Select(x => x.ToViewModel<DeviceViewModel>())
.ToList(); // this will materialize the query to a list in memory
// Now modifications of elements in the result IEnumerable will be persisted.
You can then go on with the rest of the code.
Second (and probably optional), I also recommend for clarity to use foreach to enumerate the elements. That's the C# idiomatic way to loop through an IEnumerable:
foreach (var element in result)
{
int? deviceID = element.DeviceId;
element.RoomCode = deviceRepository.GetRoomCode(deviceID);
}

Merging lists with a for loop

I'm working on an algorithm which can generate 2 types of recommendations, restaurants and dishes. All of this works fine, but I wanted to merge these 2 types of recommendations in a single list, which is where I encountered some issues. From my previous question I concluded that I needed a wrapper class, which I have set up like this:
public class RecommenderItem
{
public Guid Id { get; set; }
public object Entity { get; set; }
}
Now I want to alternate the 2 types of recommendations so the list would look like this:
[Restaurant][Dish][Restaurant][Dish][Restaurant][Dish] //Etc...
Note that these recommendations are completely separate. They are generated purely based on the user's preference, and they have no correlation in between them. My product owner wants to show these recommendations on the home page of our app like this.
These lists are different in length, so if I have added all items from a list, I wanted to just add the remaining objects from the other list. A possible scenario of this could look like this:
/*Other objects before this...*/[Dish][Restaurant][Dish][Dish][Dish] //Etc...
Here did the list of restaurant objects run out and I just wanted to add the remaining dish recommendations at the end of the list.
I have gotten this far, but I'm unsure how I would catch an IndexOutOfBounds exception and add the rest of the remaining objects at the end.
public List<RecommenderItem> GetMergedRecommendationLists(List<Restaurant> restaurantRecommendations,
List<Dish> dishRecommendations)
{
//Setting up the output list.
List<RecommenderItem> output = new List<RecommenderItem>();
int count = 0;
//Check which list is longer and use that count
if (restaurantRecommendations.Count > dishRecommendations.Count)
count = dishRecommendations.Count;
else
count = restaurantRecommendations.Count;
for (int i = 0; i < count; i++)
{
//I'm fully aware this isn't the most optimal way of doing this,
//but I'm only looking at functionality here, optimizing performance comes later.
var restRecommendation = restaurantRecommendations[i];
var dishRecommendation = dishRecommendations[i];
output.Add(new RecommenderItem()
{
Id = restRecommendation.Id,
Entity = restRecommendation
});
output.Add(new RecommenderItem()
{
Id = dishRecommendation.Id,
Entity = dishRecommendation
});
}
return output;
}
Does anyone have an idea how I could do this? Could I just catch an IndexOutOfBounds exception and use .AddRange() for the remaining objects? I'm not sure how I could check which list was out of bounds.
Let me know if I should elaborate more and thanks in advance!
Edit: -removed because it wasn't fair.-

This is a fairly succinct way of doing this.
While not Linq, it works in the spirit of the way Linq works by deferring doing any work until the resulting sequence is enumerated:
public static IEnumerable<RecommenderItem> Merge(IEnumerable<Restaurant> restaurants, IEnumerable<Dish> dishes)
{
using (var r = restaurants.GetEnumerator())
using (var d = dishes.GetEnumerator())
{
while (true)
{
bool rAvailable = r.MoveNext();
bool dAvailable = d.MoveNext();
if (rAvailable)
yield return new RecommenderItem { Id = r.Current.Id, Entity = r.Current };
if (dAvailable)
yield return new RecommenderItem { Id = d.Current.Id, Entity = d.Current };
if (!rAvailable && !dAvailable)
break;
}
}
}
If you happen to be using the MoreLinq NuGet package that includes the ZipLongest extension method, you can use the following simplified implementation instead:
public static IEnumerable<RecommenderItem> Merge(IEnumerable<Restaurant> restaurants, IEnumerable<Dish> dishes)
{
foreach (var item in restaurants.ZipLongest(dishes, (r, d) => new { r, d }))
{
if (item.r != null)
yield return new RecommenderItem { Id = item.r.Id, Entity = item.r };
if (item.d != null)
yield return new RecommenderItem { Id = item.d.Id, Entity = item.d };
}
}
Addendum
As #InBetween posted in his answer, you can put the interleaving logic into an extension method. Here's my version; it's substantially the same, except I've added a small optimisation to avoid calling .MoveNext() when its not necessary:
public static class EnumerableExt
{
public static IEnumerable<T> Interleave<T>(this IEnumerable<T> a, IEnumerable<T> b)
{
using (var ae = a.GetEnumerator())
using (var be = b.GetEnumerator())
{
bool aAvailable = true;
bool bAvailable = true;
while (aAvailable || bAvailable)
{
aAvailable = aAvailable && ae.MoveNext();
bAvailable = bAvailable && be.MoveNext();
if (aAvailable)
yield return ae.Current;
if (bAvailable)
yield return be.Current;
}
}
}
}
Once you have that, I realised that you don't need to write an implict operator. Instead, you can just convert the two sequences to the resultant type before calling Interleave() like so:
var restaurantsAsRecommenderItems =
restaurantRecommendations
.Select(r => new RecommenderItem {Id = r.Id, Entity = r});
var dishesAsRecommenderItems =
dishRecommendations
.Select(d => new RecommenderItem {Id = d.Id, Entity = d});
var result =
restaurantsAsRecommenderItems
.Interleave(dishesAsRecommenderItems)
.ToList();

My recommendation would be to just make simple implicit operator :
public static implicit operator RecommenderItem(Restaurant restaurant) {
return new RecommenderItem { Id = restaurant.Id, Entity = restaurant };
}
Then you have possibility to convert these types easily like :
Restaurant rest = //...
RecommenderItem rItem = rest; // here the implicit operator is called
After doing this you can just use one for loop :
int count = Math.Max(restaurantRecommendations.Count, dishRecommendations.Count);
for ( int i = 0; i < count; i++ ) {
if ( i < restRecommendations.Count )
output.Add(restRecommendations[i]);
if ( i < dishRecommendations.Count )
output.Add(dishRecommendations[i]);
}
This will make your work much more easier.

Well, there are probably more elegant LINQ solutions but you have already most, it's also a very efficient approach:
public List<RecommenderItem> GetMergedRecommendationLists(List<Restaurant> restaurantRecommendations, List<Dish> dishRecommendations)
{
//Setting up the output list.
List<RecommenderItem> output = new List<RecommenderItem>();
int count = Math.Min(restaurantRecommendations.Count, dishRecommendations.Count);
for (int i = 0; i < count; i++)
{
var restRecommendation = restaurantRecommendations[i];
var dishRecommendation = dishRecommendations[i];
output.Add(new RecommenderItem()
{
Id = restRecommendation.Id,
Entity = restRecommendation
});
output.Add(new RecommenderItem()
{
Id = dishRecommendation.Id,
Entity = dishRecommendation
});
}
int remainingRestaurant = restaurantRecommendations.Count - count;
int remainingDishes = dishRecommendations.Count - count;
if (remainingRestaurant > 0)
{
for (int i = count; i < restaurantRecommendations.Count; i++)
{
var restRecommendation = restaurantRecommendations[i];
output.Add(new RecommenderItem()
{
Id = restRecommendation.Id,
Entity = restRecommendation
});
}
}
else if (remainingDishes > 0)
{
for (int i = count; i < dishRecommendations.Count; i++)
{
var dishRecommendation = dishRecommendations[i];
output.Add(new RecommenderItem()
{
Id = dishRecommendation.Id,
Entity = dishRecommendation
});
}
}
return output;
}

A simple way of doing it would be:
public static IEnumerable<T> Merge<T>(this IEnumerable<T> first, IEnumerable<T> second)
{
using (var firstEnumerator = first.GetEnumerator())
using (var secondEnumerator = second.GetEnumerator())
{
while (firstEnumerator.MoveNext())
{
yield return firstEnumerator.Current;
if (secondEnumerator.MoveNext())
{
yield return secondEnumerator.Current;
}
}
while (secondEnumerator.MoveNext())
{
yield return secondEnumerator.Current;
}
}
}

After having created two arrays of restaurants and dishes of the same type RecommenderItem, you can use the Zip method like :
var restaurants = restaurantRecommendations.Select(x => new RecommenderItem {
Id = x.Id,
Entity = x
}).ToArray();
var dishes = dishRecommendations.Select(x => new RecommenderItem {
Id = x.Id,
Entity = x
}).ToArray();
var output = restaurants.Zip(dishes, (r, d) => new[] { r, d })
.SelectMany(r => r).Concat(dishes.Skip(restaurants.Length))
.Concat(restaurants.Skip(dishes.Length));

Restaraunt and Dish would have to share a base type:
restaurantRecommendations.Select(item => new RecommenderItem()
{
Id = item.Id,
Entity = item
});
dishRecommendations.Select(item => new RecommenderItem()
{
Id = item.Id,
Entity = item
});
Once that's the case you could use something like this slightly modified version of Zip (from System.Linq):
private static IEnumerable<T> ZipThrough<T>(IEnumerable<T> first, IEnumerable<T> second)
{
if (first == null) throw new ArgumentNullException(nameof(first));
if (second == null) throw new ArgumentNullException(nameof(second));
using (var e1 = first.GetEnumerator())
{
using (var e2 = second.GetEnumerator())
{
while (true)
if (e1.MoveNext())
{
yield return e1.Current;
if (e2.MoveNext()) yield return e2.Current;
}
else if (e2.MoveNext())
{
yield return e2.Current;
}
else
{
break;
}
}
}
}

Problems with LINQ WhereClause

Many thanks to leppie:
Currently I got
Expression<Func<vwMailMerge,bool>> whereClause= null;
List<vwMailMerge> mailMergeItems = null;
int personType = mailMergeSettings.PersonType.ToInteger();
if (personType > 0)
{
whereClause = this.MailMergeWhereClause(whereClause, f => f.MemberTypeId == personType);
}
if (mailMergeSettings.PersonIds != null)
{
var personIds = mailMergeSettings.PersonIds.ToGuidArray();
if (personIds != null && personIds.Length > 0)
{
var personList = personIds.ToList();
whereClause = this.MailMergeWhereClause(whereClause, f => personList.Contains(f.UserId));
}
}
mailMergeItems = this.ObjectContext.vwMailMerges.Where(whereClause).ToList();
private Expression<Func<vwMailMerge, bool>> MailMergeWhereClause(params Expression<Func<vwMailMerge, bool>>[] wheres)
{
if (wheres.Length == 0)
{
return x => true;
}
Expression result;
if (wheres[0] == null)
{
result = wheres[1].Body;
return Expression.Lambda<Func<vwMailMerge, bool>>(result, wheres[1].Parameters);
}
else
{
result = wheres[0].Body;
for (int i = 1; i < wheres.Length; i++)
{
result = Expression.And(result, wheres[i].Body);
}
return Expression.Lambda<Func<vwMailMerge, bool>>(result, wheres[0].Parameters);
}
}
}
When it gets to "mailMergeItems =" it drops and gives error: "The parameter 'f' was not bound in the specified LINQ to Entities query expression."
I've noticed that when checking only for people, or only for membertypeId, it works properly.. but combined the 2nd gives a error on it's "f=>" I think.

You cant use Func, you need to use Expression<Func>.
The + can be done via Expression.And.
Update (not tested):
Expression<Func<vwMailMerge, bool>> whereClause = null;
...
Expression<Func<vwMailMerge, bool>> MailMergeWhereClause(
params Expression<Func<vwMailMerge, bool>>[] wheres)
{
if (wheres.Length == 0) return x => true;
Expression result = wheres[0].Body;
for (int i = 1; i < wheres.Length; i++)
{
//probaby needs a parameter fixup, exercise for reader
result = Expression.And(result, wheres[i].Body);
}
return Expression.Lambda<Func<vwMailMerge,bool>>(result, wheres[0].Parameters);
}
Update 2:
The above approach fails as I expected. It might be easy to solve on .NET 4 using the ExpressionVistor class. For .NET 3.5 (or if aforementioned is too hard) the following should work.
The approach is the append the where clauses in the IQueryable directly so you end up with:
somequery.Where(x => x.foo).Where(x => x.bar).Where(x => x.baz)
IOW, you can just add them as required, but it will require some changes to the logic/flow of the code you pasted.

You could reformat your question better with the code tool.
However it looks like you could approach the problem in this way to avoid all those func expressions floating around:
this.ObjectContext.vwMailMerges.Where(mm=>IsValidMailMerge(mm,personType)).ToList()
private bool IsValidMailMerge(YourType mailmerge, YourType2 personType)
{
if(...) // type specific criteria here
return true;
else
return false;
}

C# LINQ question about foreach

is there any way to write this foreach in linq or another better way,
int itemNr = -1;
foreach(ItemDoc itemDoc in handOverDoc.Assignment.Items) {
itemNr++;
foreach(ItemDetailDoc detail in itemDoc.Details) {
int eventDocNr = -1;
foreach(EventDoc eventDoc in detail.Events) {
eventDocNr++;
if(!eventDoc.HasEAN) {
HideShowPanels(pMatch);
txt_EAN.Text = String.Empty;
lbl_Match_ArtName.Text = itemDoc.Name;
lbl_ArtNr.Text = itemDoc.Number;
lbl_unitDesc.Text = eventDoc.Description;
m_tempItemNr = itemNr;
m_tempEventNr = eventDocNr;
txt_EAN.Focus();
return;
}
}
}
}
I just think this is not the correct way to write it. please advise.

If itemNr and eventDocNr is not needed you could use:
var item =
(from itemDoc in handOverDoc.Assignment.Items
from detail in itemDoc.Details
from eventDoc in detail.Events
where !eventDoc.HasEAN
select new
{
Name = itemDoc.Name,
Number = itemDoc.Number,
Description = eventDoc.Description
}).FirstOrDefault();
if (item != null)
{
HideShowPanels(pMatch);
txt_EAN.Text = String.Empty;
lbl_Match_ArtName.Text = item.Name;
lbl_ArtNr.Text = item.Number;
lbl_unitDesc.Text = item.Description;
txt_EAN.Focus();
}

No, I dont think there is a better way to do that. LINQ is about queries, you do quite a lot of processing in there. Unless you have a shortcut that is not obvious here.... this seems t obe the only way.
If you COULD start from the eventDoc - you could filter out those without EAN and then go from there backward, but Ican not say how feasible that is as I miss the complete model (as in: maybe you have no back lniks, so you would be stuck wit hthe eventDoc an dcoul dnot get up to the item.
First look that looks fine.

You could try the following LINQ:
var nonEANs = from ItemDoc itemDocs in itemDocList
from ItemDetailDoc itemDetailDocs in itemDocs.Details
from EventDoc eventDocs in itemDetailDocs.Events
where !eventDocs.HasEAN
select eventDocs;
foreach (var i in nonEANs)
{
System.Diagnostics.Debug.WriteLine( i.HasEAN);
}
Should return 7 false EANs: I recreated you nested structures like this
List<ItemDoc> itemDocList = new List<ItemDoc>()
{
new ItemDoc()
{
Details = new List<ItemDetailDoc>()
{
new ItemDetailDoc()
{
Events = new List<EventDoc>()
{
new EventDoc()
{HasEAN=false},
new EventDoc()
{HasEAN=false}
}
},
new ItemDetailDoc()
{
Events = new List<EventDoc>()
{
new EventDoc()
{HasEAN=true},
new EventDoc()
{HasEAN=false}
}
}
}
},
new ItemDoc()
{
Details = new List<ItemDetailDoc>()
{
new ItemDetailDoc()
{
Events = new List<EventDoc>()
{
new EventDoc()
{HasEAN=false},
new EventDoc()
{HasEAN=false}
}
},
new ItemDetailDoc()
{
Events = new List<EventDoc>()
{
new EventDoc()
{HasEAN=false},
new EventDoc()
{HasEAN=false}
}
}
}
}
};

I think you are stuck with the for each loops as you need the itemNr and eventDocNr. You can use for loops to avoid increasing the itemNr and eventDocNr, but this does not reduce the number of loops.
Edit:
And if you do need the itemNr and eventDocNr try this:
var query = handOverDoc.Assignment.Items
.SelectMany(
(x, i) => x.Details.SelectMany(
(d, di) => d.Events.Where(x => x.HasEAN).Select(
(e, ei) => new {
ItemIndex = di,
EventIndex = ei,
Detail = d,
Event = e
}
)
)
);
foreach (var eventInfo in query) {
HideShowPanels(pMatch);
txt_EAN.Text = String.Empty;
lbl_Match_ArtName.Text = eventInfo.Detail.Name;
lbl_ArtNr.Text = eventInfo.Detail.Number;
lbl_unitDesc.Text = eventInfo.Event.Description;
txt_EAN.Focus();
return;
}
If you need only the first event with an EAN you could also use the following on the above query:
var item = query.FirstOrDefault();
if (item != null) {
// do you stuff here
}

You can get the index in LINQ quite easily, for example :-
var itemDocs = handOverDoc.Assignment.Items.Select((h, i) => new { item = h, itemindex = i })
You can repeat this process for your inner loops also and I suspect you could then use SelectMany() to simplify it even further.

You're trying to do two different things here. Firstly you're trying to find a document, and secondly you're trying to change things based upon it. The first stage in the process is simply to clarify the code you already have, e.g.
(Note this takes into account previous comments that the computed indexes in the original code are not needed. The exact same type of split into two methods could be done whether or not the computed indexes are required, and it would still improve the original code.)
public void FindAndDisplayEventDocWithoutEAN(HandOverDoc handOverDoc)
{
var eventDoc = FindEventDocWithoutEAN(handOverDoc);
if (eventDoc != null)
{
Display(eventDoc);
}
}
public EventDoc FindEventDocWithoutEAN(HandOverDoc handOverDoc)
{
foreach(ItemDoc itemDoc in handOverDoc.Assignment.Items)
foreach(ItemDetailDoc detail in itemDoc.Details)
foreach(EventDoc eventDoc in detail.Events)
if(!eventDoc.HasEAN)
return eventDoc;
return null;
}
public void Display(EventDoc eventDoc)
{
HideShowPanels(pMatch);
txt_EAN.Text = String.Empty;
lbl_Match_ArtName.Text = itemDoc.Name;
lbl_ArtNr.Text = itemDoc.Number;
lbl_unitDesc.Text = eventDoc.Description;
m_tempItemNr = itemNr;
m_tempEventNr = eventDocNr;
txt_EAN.Focus();
}
Once you've done that, you should be able to see that one method is a query over the main document, and the other is a method to display the results of the query. This is what's known as the single responsibility principle, where each method does one thing, and is named after what it does.
The transformation of the nested foreach loops to a linq query is now almost trivial. Compare the method below with the method above, and you can see how mechanical it is to translate nested foreach loops into a linq query.
public EventDoc FindEventDocWithoutEAN(HandOverDoc handOverDoc)
{
return (from itemDoc in handOverDoc.Assignment.Items
from detail in itemDoc.Details
from eventDoc in detail.Events
where !eventDoc.HasEAN
select eventDoc).FirstOrDefault();
}

yet another spin...
var query = from itemDocVI in handOverDoc.Assignment
.Items
.Select((v, i) => new { v, i })
let itemDoc = itemDocVI.v
let itemNr = itemDocVI.i
from detail in itemDoc.Details
from eventDocVI in detail.Events
.Select((v, i) => new { v, i })
let eventDoc = eventDocVI.v
let eventDocNr = eventDocVI.i
where eventDoc.HasEAN
select new
{
itemDoc,
itemNr,
detail,
eventDoc,
eventDocNr
};
var item = query.FirstOrDefault();
if (item != null)
{
HideShowPanels(pMatch);
txt_EAN.Text = String.Empty;
lbl_Match_ArtName.Text = item.itemDoc.Name;
lbl_ArtNr.Text = item.itemDoc.Number;
lbl_unitDesc.Text = item.eventDoc.Description;
m_tempItemNr = item.itemNr;
m_tempEventNr = item.eventDocNr;
txt_EAN.Focus();
}