C# - Getting The Values From A Grouped Row Using LINQ?
Dec 17, 2010
I have the following class:
public class MySeat
{
public string Section { get; set; }
public string Row { get; set; }
public string Seat {get; set; }
}
I want to group a list of seats by the Section and Row so that I can make a comma seperated list of the seats.
var groupedSeats = seats.GroupBy(x => new { x.Section, x.Row });
foreach (var group in groupedSeats)
{
htmlWriter.Write(group.Key.Section);
List<string> seatNumbers = new List<string>();
foreach (var seat in group)
seatNumbers.Add(seat.Seat);
htmlWriter.Write(string.Join(@", ", seatNumbers.ToArray()));
}
Is there a better way to do this with LINQ? This is just a small portion of the code I'm trying to clean up, I'm curious if there is a better way to grab the seat numbers for display rather than creating a list, looping through the groups and then doing a string.Join on it.
Prior to using a ViewModel, I could easily pass the "soon to be edited" object directly to the view without needing to fuss over setting individual properties etc as the View conveniently accepted the Employee type directly..
[HttpGet] public ActionResult EditEmployee(int? id) { EmployeeRepository ER = new EmployeeRepository(); Employee SomeEmployee = ER.GetEmployee(id.Value); if(SomeEmployee!=null) return View(SomeEmployee);
But now I'm using a ViewModel with DataAnnotations attributes applied over the top of various properties for validation purposes. Which creates a problem.. After fetching the "soon to be edited" object from the db, setting the ViewModel's values is suddenly a whole lot more complicated. I can't simply pass the retrieved object straight to the view, as the View now expects the VMEmployee type instead. I would like to be able to do something like:
[HttpGet] public ActionResult EditEmployee(int? id) { EmployeeRepository ER = new EmployeeRepository(); Employee SomeEmployee = ER.GetEmployee(id.Value); if(SomeEmployee!=null) return View(new VMEmployee(SomeEmployee));
All paths seem to lead to a huge constructor which manually sets the values of each individual property. But I never had to do that before when I wasn't using a ViewModel. Model binding was a blessing! My objects also have complex child objects, which my form is also collecting values for, so this would be a huge/verbose task against DRY principals. I don't even really want to use a ViewModel, but am forced to because I need two different DataAnnotations rule sets for different validation scenarios applied to the same object.
All I want to do is be able to have two different DataAnnotations rule sets for different scenarios. I.e. public-facing www site vs internal-facing admin site. DataAnnotations doesn't seem to be flexible enough to easily cater for this common need. I've tried AutoMapper, but it throws an error saying it can't map my object types, I suspect because Employee was auto-generated by LINQ to SQL. What is the most elegant way to achieve this while sticking to DRY principals?
I've got a LINQ to SQL object, and I want to group the selected data and then pass it into a view. What's the correct way of doing this? I'm sure I need to group the data when I select it rather than grouping it in the view, as this will result in about 200 rather 50000 rows I need to pass into my view. Are there any good examples of this online that anyone has seen?
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However, I can't work out an effective way to show the various products groupd by manufacturer, eg as shown below;
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- Session 1 - New Book A - Used Book A - Session 2 - New Book B - Used Book B
I've tried using HTML <input type="radio", and <asp:RadioButton, but even though I assign the "name" attribute correctly, the buttons are not mutually exclusive -- i.e., you can click both within each group. I see in "View Source" that the name and ID are altered, and therefore become ungrouped by the ASP.NET processing. I've tried using <asp:RadioButtonList, and this works functionally, but the items are not grouped properly. They appear like this:
- Session 1 - Session 2 - New Book A - Used Book A - New Book B - Used Book B
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California Entry 1 Entry 2 Entry 3 New York Entry 1 Entry 2 Entry 3
Other (for entries with no state)
Entry 1 Entry 2
What would be the best method to do this? And I'm open to using anything up to and including .net 4.0/vs2010
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I'm building a music voting application, similar to stack overflow almost.I have 3 tables, Charts, ChartItems, Votes.I'm trying to bring back a list of chartitems, which link to a single chart, with the number of votes for each chart item counted.This is what I am trying currently
var firstList = from chartItem in db.ChartItems join vote in db.Votes on chartItem.ixChartId equals vote.ixChartId into j1 where chartItem.ixChartId == id[code]...
The problem is once I have performed the grouping, I can't get any of the other properties I need from the join to populate the model. For example each ChartItem should have a title, id etc...I have created a ViewModel to hold all the properties that I need, called ChartItemWithVotes(includes all entity values + int totalVotes)In the end I am looking for this
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SELECT * FROM x UNION SELECT * FROM y UNION SELECT * FROM Z ORDER By v_alue1
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I have a public class Color which just has one property which I can then use as the DataTextField and DataValueField for the dropdownlist
[code]...
However this never results in the distinct colors.
I have searched and searched for what I am looking for, and this seems to be one of the methods to produce a distinct set of results, but this and the others do not work.
My reasoning behind getting the colors this way, is that I need to get various other distinct values from the same UNION SELECT datasource, so would just do one DB call, cache the results, and then just used this cached datasource to retrieve all my distinct values.
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var clientquer = from i in Entity.New_Bank select i; //var q = (from s in names // select s).Distinct(); // var getlendername = (from db in mortgageentity.New_Lender group db by db.Bank_Name into t select t.Key).ToList(); if (clientquer.Count() > 0) { ddlbankname.DataSource = clientquer.ToList(); ddlbankname.DataValueField = "Bank_ID2"; ddlbankname.DataTextField = "Bank_Name"; ddlbankname.DataBind(); }
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I have what is turning out to be a rather complicated issue - at least for me.
I have a table with TeamID, TeamName, TotalTeamSize, ArrivalDate adn DepartureDate.
I need to create a source for a bar chart that will show the number of people deployed each month. It can be assumed that the entire team is dployed for each of the days between the ArrivalDate and the DepartureDate. Sometimes the ArrivalDate/DepartureDate spans two months (very rarely more) and sometimes it does not.
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All I need to do is the learn the syntax, that allows LINQ to Entities to query only some of the data from UserProfiles. For example, maybe I only need Sex and Weight, but not Age.
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