Develop Reference

How to pass multiple keys to array in ASP Web Api?

I need to write ASP Web Api code which will take users input in this format:
"GenreName" : "Rock",
"Songs":[
"SongName":"Song 1",
"Length":233,
"Composer":"Composer 1"
],
[
"SongName":"Song 2",
"Length":221,
"Composer":"Composer 2"
]
The values are being sent with Postman using JSON. I have figured out to use string[] SongName to add list of songs, but i need to pass additional keys so all columns in SQL can be filled such as length and composer. The thing troubling me is how to place all these values into array and then loop them with foreach. Below is the code i have managed to come up so far:
public void Execute(InsertDTO request)
{
var genre = request.GenreName;
var datum = request.Datum;
var trackname = request.TrackName;
//var add = new Genre
//{
// Name = genre
//};
//context.Genre.Add(add);
// int id = add.GenreId;
var check = context.Genre.Where(x=>x.Name == request.GenreName).Count();
// var chek2= context.Track.Where(x=>x.Name==request.Tracks.con)
if (datum > DateTime.Now)
{
throw new ArgumentException("datum ne moze biti u buducnosti");
}
else
{
Genre g = new Genre
{
Name = genre,
Datum = datum
};
context.Genre.Add(g);
context.SaveChanges();
var id = g.GenreId;
foreach (var t in trackname) {
var pesma = t;
Track track = new Track
{
MediaTypeId=1,
GenreId = id,
Name=pesma
};
context.Track.Add(track);
context.SaveChanges();
}
}
}
InsertDTO.cs
public class InsertDTO
{
// public int GenreId { get; set; }
public string GenreName { get; set; }
public DateTime Datum { get; set; }
public string[] TrackName { get; set; }
}
}
Help is greatly appreciated!

Since your code sample doesn't show the API call, it may be hard to provide an answer. In my experience, converting your InsertDTO model into a JSON string then passing the JSON string to the Web API is the correct move.
Can i use JSON.Stringify in code-behind of an ASP.Net project
var jsonStr = new JavaScriptSerializer().Serialize(myModel);

Filter Data based on same ID

I have a model class
public class Model
{
public string name { get; set; }
public string files { get; set; }
}
I have a controller class that populates the data from database into this model
List<Model> model = new List<Model>();
while (reader.Read()){
var om = new Model();
if (reader != null)
{
om.name = reader.GetString(0);
om.files = reader.GetString(1);
model.Add(om)
}
How can I filter and combine all files that have the similar first names?
I read about linq and tried this
var jm = om.name
.Where(o => om.name.Contains(o))
.Select() ;

This might work for you:
var grouped = model.GroupBy(m => m.name).ToArray();
This will create an object grouped of type IGrouping<string, Model>[] (array of IGrouping...)
.ToArray() is optional and if you remove it, you get IEnumerable<IGrouping<string, Model>>, but don't let the nested <> scare you.
The items in your original list are grouped by name, so the group will have Key property that will be the same for each element in the group.
To print the results, for example:
foreach(var group in grouped)
{
Console.WriteLine($"Printing group: {group.Key}");
foreach(var model in group)
{
Console.WriteLine($"\tName: {model.name}, File: {model.file}");
}
}
Note that each element in a group is a collection of your model objects.
Use debugger to see what that structure looks like and if you need more help - ask...

Change your Model
public class Model
{
public string name { get; set; }
public IList<string> files { get; set; }
}
Use a Dictionary.
var models = new Dictionary<string, Model>();
while (reader.Read())
{
var om = new Model();
if (reader != null)
{
var name = reader.GetString(0);
var file = reader.GetString(1);
if (models.Contains(name))
models[name].files.Add(file);
else
{
models.Add(name, new Model
{
name = name,
files = new List<string>{files}
});
}
}
}
Then you can pull out a combined list with LINQ:
var peopleFileLists = models.Select(x => x.Value).ToList();
foreach(var person in peopleFileLists)
{
foreach(var file in person.files)
Console.WriteLine(person.name + "-" + file);
}

Group By query in mvc5

Hi i want to write sql Group by query in C# of my MVC5 application.
In the above image I have group by query which i wrote in sql . That I want to write in C# front end.
I tried to write query in front end. But I am getting error which is mentioned in the image. Now I want to write that Group By query in C# and want to display the each employee with count (output same as mentioned in the first image). Can anyone help me to resolve this issue?
My ViewModel(Dashnboard View model)
public class DashboardViewmodel
{
public List<CustomerTypeCountModel> CustomerTypesCountModels { get; set; }
public List<View_VisitorsForm> Visits { get; set; }
public CustomerTypeViewModel CustomerTypeViewModels { get; set; }
public int sizingcount { get; set; }
public int Processingcount { get; set; }
//here i declared two properties
public string EmployeeName { get; set; }
public string EmployeeCount { get; set; }
}
My Controller code
[HttpGet]
public ActionResult SalesVisit()
{
return View();
}
public ActionResult GetDatesFromSalesVisit(DashboardViewmodel dvm)
{
var fromdate = Convert.ToDateTime(dvm.CustomerTypeViewModels.FromDate);
var todate = Convert.ToDateTime(dvm.CustomerTypeViewModels.ToDate);
List<View_VisitorsForm> empcount = new List<View_VisitorsForm>();
if (DepartmentID == new Guid("47D2C992-1CB6-44AA-91CA-6AA3C338447E") &&
(UserTypeID == new Guid("106D02CC-7DC2-42BF-AC6F-D683ADDC1824") ||
(UserTypeID == new Guid("B3728982-0016-4562-BF73-E9B8B99BD501"))))
{
var empcountresult = db.View_VisitorsForm.GroupBy(G => G.Employee)
.Select(e => new
{
employee = e.Key,
count = e.Count()
}).ToList();
empcount = empcountresult ;//this line i am getting error
}
DashboardViewmodel obj = new DashboardViewmodel();
return View("SalesVisit", obj);
}

When you use a GroupBy you get an IEnumerable<IGrouping<Key,YourOriginalType>> so you do not have .Employee and .VisitingID properties.
Change as following:
public class EmployeeCount
{
public string Employee {get; set;}
public int Count {get; set;}
}
List<EmployeeCount> result = db.View_VisitorsForm
.Where(item => item.VisitingDate >= beginDate && item.VisitingDate < endDate)
.GroupBy(G => G.Employee)
.Select(e =>new EmployeeCount
{
employee = e.Key,
count = e.Count()
}).ToList();
//Now add the result to the object you are passing to the View
Also keep in mind that you are not instantiating objects of type View_VisitorsForm but an anonymous object so assigning the result to empcount yet alone with the added FirstOrDefault will not compile
To pass this structure to the View and present it check this question

hope this helps you
var query = db.View_VisitorsForm.Where(o => o.VisitingDate >= new DateTime(2016,10,01) && o.VisitingDate <= new DateTime(2016, 10, 30)).GroupBy(G => G.Employee)
foreach (var item in query)
{
Console.WriteLine($"Employee Id {item.Key} : Count :{item.Count()}");
}

Orderby a string column in linq causes an error

I have a query like this :
List<PresentClass.userpresentation> q =
(dbconnect.tblUsers.Where(
i => i.permission == permission)
.Select(arg => new PresentClass.userpresentation {
email = arg.email, pass = arg.password,
name = arg.name+" "+arg.family })).ToList();
After adding an orderby :
List<PresentClass.userpresentation> q =
(dbconnect.tblUsers.Where(
i => i.permission == permission)
.Select(arg => new PresentClass.userpresentation {
email = arg.email, pass = arg.password,
name = arg.name+" "+arg.family })).OrderBy(i=>i.family).ToList();
I got this error :
The member
'Novitiate.AdminPortal.PresentationClass.PresentClass+userpresentation.family'
has no supported translation to SQL.
My class:
public class userpresentation
{
public string username { set; get; }
public string email { set; get; }
public string family { set; get; }
public string name { set; get; }
public string pass{ set; get; }
}
Why?

It looks like it's trying to translate the OrderBy() into a SQL statement on your projection.
Try adding the OrderBy() before Select() if you want the database to do the ordering, or after the ToList() if you want to do the ordering once the collection has been loaded.
var q = (dbconnect.tblUsers.Where(i => i.permission == permission)
.OrderBy(i=>i.family)
.Select(arg => new PresentClass.userpresentation {
email = arg.email,
pass = arg.password,
name = arg.name+" "+arg.family
})).ToList();

parse a string with name-value pairs

How can I parse the following string of name-value pair in C#:
string studentDetail = "StudentId=J1123,FirstName=Jack,LastName=Welch,StudentId=k3342,FirstName=Steve,LastName=Smith"
The purpose of parsing this array is to insert values in DB using Linq to SQL:
[HttpPost]
public ActionResult SaveStudent(string studentDetail)
{
DataContext db = new DataContext();
Student student = new Student();
{
student.StudentID = //StudentID
student.FirstName = //FirstName
student.LastName = //LastName
};
db.Student.InsertOnSubmit(student);
db.SubmitChanges();
return View();
}
What is the best way of approaching this?

You can split on the comma, then on the equals sign. I put the data into a dictionary for easy access.
string input = "StudentId=J1123,FirstName=Jack,LastName=Welch";
Dictionary<string,string> keyValuePairs = input.Split(',')
.Select(value => value.Split('='))
.ToDictionary(pair => pair[0], pair => pair[1]);
string studentId = keyValuePairs["StudentId"];
Note that this isn't validating the input at all to ensure that there are no commas in values, no keys without values, missing keys, etc.

Because the individual student records are not delimited in the input, I would do something like the following:
public class Student
{
public string Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
and then:
private List<Student> DoSplit(string input)
{
var theReturn = new List<Student>();
input = input.Replace(",StudentId=", "|,StudentId=");
var students = input.Split('|');
foreach (var student in students)
{
var attribs = student.Split(',');
if (attribs.Count() == 3)
{
var s = new Student();
s.Id = attribs[0].Substring(attribs[0].LastIndexOf('='));
s.FirstName = attribs[1].Substring(attribs[1].LastIndexOf('='));
s.LastName = attribs[2].Substring(attribs[2].LastIndexOf('='));
theReturn.Add(s);
}
}
return theReturn;
}
Again, it's a bit naive because if content contains "=", ",", or "|", there will be failures. You should add some checking in there as well.

Eric Petroelje had a very nice answer at https://stackoverflow.com/a/2049079/59996
Try System.Web.HttpUtility.ParseQueryString, passing in everything
after the question mark. You would need to use the System.Web
assembly, but it shouldn't require a web context.
(I'm not sure why these two questions aren't linked)
I was able to parse a string of the form a=1&b=2&c=3 using the following code
NameValueCollection nameValueCollection = HttpUtility.ParseQueryString(submission);