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Why nested foreach in linq works after all operations? [closed]

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Please tell me why in this case the last instruction from the Combine (Where) method will work before the logic in foreach (Bar method). The example is completely artificial.
public class TestLinq
{
public static class Foo
{
public static IEnumerable<FooObject> Bar(ICollection<FooObject> forrObjects)
{
return forrObjects
.Where(fooObject => AnyConditions(fooObject))
.GroupBy(fooObject => fooObject.AnyProp)
.SelectMany(foofData =>
{
foreach (var foo in foofData)
{
foo.Flags |= TestFlag;
}
return new[]
{
new BarObject(foofData.First()),
new BarObject(foofData.First()),
};
});
}
}
public FooObject[] Combine(ICollection<FooObject> fooObjects)
{
return fooObjects
.Union(Foo.Bar(fooObjects))
.Where(foo => !foo.Flags.HasFlag(TestFlag))
.ToArray();
}
}
I used debug and found out the order of execution, I want to understand why it works this way

Add content to list [closed]

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How can I proceed to add in the list the content of my foreach, without deleting the previous content?
lSave.Add(NextKey, new LSave());
foreach (var container in corpse.containers)
lSave[NextKey].items = GetItems(container).ToList();
And the Structure
public Dictionary<uint, LSave> lSave = new Dictionary<uint, LSave>();
public class LSave
{
public List<LItems> items;
public LSave() { }
}
public class LItems
{
public string name;
}
IEnumerable<LItems> GetItems(ItemContainer container)
Thanks

If you want to add more items to a specific key in the dictionary, try this:
foreach (var container in corpse.containers)
{
LSave item;
if (!lSave.TryGetValue(NextKey, out item))
{
item = new LSave();
item.items = new List<LItems>();
lSave.Add(NextKey, item);
}
item.items.AddRange(GetItems(container));
}
It adds an LSave to NextKey if needed and then adds the result of GetItems(container) to the items field of that LSave.

C# how does this code work? [closed]

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Public class form1
{
List<Data> dataInfo = new List<Data>();
private void UpdateBinding()
{
supplierBox.DataSource = dataInfo;
supplierBox.DisplayMember = "Supplier";
}
}
I have another class called Data:
public class Data
{
public string Supplier { get; set; }
}
This is able to update my textBox named supplier on Visual Studio with data from my SQL Server that I have grabbed. How would I access the data from my SQL Server if I just wanted to put it in a variable like var?

supplier.Text = dataInfo.FirstOrDefault().Supplier;
would place the first element from your list of suppliers into your text box named "suppliers". If you don't have any items in your list of dataInfo then you would get a NullReferenceException.

Have Required Attribute apply to property in one view and not another? [closed]

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Say I have a class called Test and I have a Create and Edit view. Say this class is incredibly simple
public class Test
{
[Required]
public string str { get; set; }
}
Is it possible to remove the required attribute when a user is editing this object?

ViewModels are there for this. One for Create and one for Edit.
You should use a ViewModel for this, as you need View Specific Models here :
public class CreateTestViewModel
{
[Required]
public string str { get; set; }
}
and:
public class EditTestViewModel
{
public string str { get; set; }
}
You might want to read about What is ViewModel in MVC and How to use ViewModel in MVC

loop to find parent id [closed]

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Is it possible in C# to carry out a loop to find the parent id for a particular page?
Here's the scenario: I'm developing a breadcrumb. For each page I need the parent Id, so I can use that to populate a list with a url and a page title.
1st page --- Parent page --- Grandparent page
I need to be able to do a loop to gather the parent id, then that will populate the list which goes through and finds the new parent page parent id (basically for the grandparent page) and then populates the list until there aren't any more.
At the moment the current page data is stored in var pageInSiteMap:
var overview = new List<PageDataModel>();
pageInSiteMap // A get command is used to place the data in here
if(pageInSiteMap != null && pageInSiteMap.ParentId.HasValue)
{
var parent = allpages.Data.Items.FirstOrDefault(x => x.Id == pageInSiteMap.ParentId
var parentEntry = new PageDataModel{
pageUrl = parent.Url, pageTitle = parent.Title
};
overview.Add(parentEntry);
}

I am going to take a stab at this and assume you need recursion, here is a quick example I wrote:
public class Page
{
public int PageId { get; set; }
public string PageTitle { get; set; }
public Page Parent { get; set; }
}
public class Class1
{
public List<Page> GetPages(Page currentPage)
{
var ret = new List<Page> {currentPage};
if(currentPage.Parent != null)
ret.AddRange(GetPages(currentPage.Parent));
return ret;
}
}