Is any way to select all fields in a query but modifying one field like this?
var notes = from n in myContext.Notes
select new
{
... // all fiedls
date = n.date.ToString("MM/YYYY") // but one field edited
}
this is the query I want but less verbose when I have several properties.
var note = await _dbContext.ClientChartNotes
.Select(s => new
{
s.ClientChartNoteId,
s.ClientId,
s.ChartNoteType,
s.Title,
s.Note,
ChartNoteDate = s.ChartNoteDate.ToString("MM/dd/yyyy")
})
.FirstOrDefaultAsync(s => s.ClientChartNoteId.Equals(id));
Lambda preferred.
Thanks
Edit: to include original query.
I recommend selecting the Note itself and the additional field.
var notes = from n in myContext.Notes
select new
{
Note= n
NewDate = n.date.ToString("MM/YYYY")
}
So your notes will have all the Original Note and the additional properties you added in the result.
Your query using lambda:
var fetchedNote = await myDbContext.Notes // get the collection of all Notes
.Where(note => note.ClientChartNoteId == Id) // take only those notes that ...
.Select(note => new // from every remaining note, make one new object
{ // with only the properties you plan to use
Title = note.Title, // some are original values
...
Date = note.Data.ToString(...), // some are calculated values
})
.FirstOrDefaultAsync();
Related
Well, im doing a linq query to get a list of results with the same column, and then i need to replace that column value with a new one.
First Code:
var db = GetContext();
var result = from f in GetContext().ProjectStateHistories
where f.ProjectId.Equals(oldProjectId)
select f;
foreach (var item in result)
{
var projectStateHistoryUpdate = db.ProjectStateHistories.Find(item.Id);
projectStateHistoryUpdate.ProjectId = newProjectId;
db.Entry(projectStateHistoryUpdate).State = EntityState.Modified;
}
db.SaveChanges();
I searched for some answers, and i found that i can use Select, and make a new object (Linq replace null/empty value with another value)
Second Code:
var result = (from f in GetContext().ProjectStateHistories
where f.ProjectId.Equals(oldProjectId)
select f).Select(d=> new { Id = d.Id, EventName = d.EventName, LogUser = d.LogUser, ProjectId = newProjectId, TimeStamp = d.TimeStamp });
And even, Third Code:
var db = GetContext();
var result = (from f in db.ProjectStateHistories
where f.ProjectId.Equals(oldProjectId)
select f).Select(d=> new { ProjectId = newProjectId});
But only the First Code works.
I wanted to ask what i am doing wrong, since i think it is better to change the value with a query, instead of using a foreach.
See code below:
var db = GetContext();
(from f in db.ProjectStateHistories
where f.ProjectId.Equals(oldProjectId)
select f)
.ToList()
.ForEach(i => i.ProjectId = newProjectId);
db.SaveChanges();
Alternatively:
var db = GetContext();
db.ProjectStateHistories
.Where(f => f.ProjectId.Equals(oldProjectId))
.ToList()
.ForEach(f => f.ProjectId = newProjectId);
db.SaveChanges();
The shortest way I know of to replace your code is this:
var db = getcontext();
db.ProjectStateHistories
.Where(f => f.ProjectId.Equals(oldProjectId))
.ToList()
.ForEach(f => f.ProjectId = newProjectId);
db.SaveChanges();
Other answers can be found here
I've just had a thought that could help you, I am just free coding here!
If you just put the for each as part of the select, and then save your changes will that work?
foreach (var source in db.ProjectStateHistories.Where(x => x.ProjectId == oldProjectId))
{
source.ProjectId= newProjectId;
db.Entry(source).State = EntityState.Modified;
}
db.SaveChanges();
I think this is a more efficient way of doing it.
Also the .Select() method is only really useful if you need to Project to a view Model, it won't change the variables in the database, just show them in the newly declared object.
Thanks,
Phill
I am trying get the data which is contains single word with in the word.Like below query.
List<Models.tbluser> memberslist = new List<Models.tbluser>();
var obct = (from memlist in objcontext.tblusers
where memlist.logname.Contains(member)
select new
{
userid = memlist.userid,
logname = memlist.logname,
decription = memlist.description
}).ToList();
foreach (var item in obct)
{
memberslist.Add(new tbluser
{
userid = item.userid,
logname = item.logname,
description = item.decription
});
}
return Json(memberslist);
But here my problem is i need to search with out case sensitive.
For example
If i search with 'a' i need to get data like Admin,Administrator,User Data.
But i am not getting all these because i am searching with Contains() method.Please let me know how can i get all value either the search value is case sensitive less also.
Change your where condition to be:
memlist.logname.ToUpper().Contains(member.ToUpper())
As a side note, you can shorten your query a bit (you don't need to create an intermediary list):
var memberslist = objcontext.tblusers
.Where(x => x.logname.ToUpper().Contains(member.ToUpper())
.AsEnumerable()
.Select(x => new tbluser
{
userid = x.userid,
logname = x.logname,
decription = x.description
})
.ToList();
return Json(memberslist);
You can change them to Lower or Upper Case when checking the condition using ToLower() or ToUpper():
var obct = (from memlist in objcontext.tblusers
where memlist.logname.ToLower().Contains(member.ToLower())
select new
{
userid = memlist.userid,
logname = memlist.logname,
decription = memlist.description
}).ToList();
I have this need to know how many rows have the same month from a table and I have no idea of how to do it. I thought I'd try some LINQ but I've never used it before so I don't even know if it's possible. Please help me out!
public ActionResult returTest()
{
ViewData["RowsWithSameMonth"] = // I'm guessing I can put some LINQ here?
var returer = from s in db2.ReturerDB select s;
return View(returer.ToList());
}
The ideal would be to get, maybe a two dimensional array with the month in the first cell and the amount of rows from the db in the second?
I'd like the result to be sort of :
string[,] statistics = new string[,]
{
{"2013-11", "5"},
{"2013-12", "10"},
{"2014-01", "3"}
};
Is this doable? Or should I just query the database and do a whole lot of stuff? I'm thinking that I can solve this on my own, but it would mean a lot of ugly code. Background: self taught C# developer at IT-company with 1 years experience of ugly codesmanship and no official degree of any kind.
EDIT
var returer = from s in db2.ReturerDB select s;
var dateRange = returer.ToList();
var groupedData = dateRange.GroupBy(dateRow => dateRow.ToString())
.OrderBy(monthGroup => monthGroup.Key)
.Select(monthGroup => new
{
Month = monthGroup.Key,
MountCount = monthGroup.Count()
});
string test01 = "";
string test02 = "";
foreach (var item in groupedData)
{
test01 = item.Month.ToString();
test02 = item.MountCount.ToString();
}
In debug, test01 is "Namespace.Models.ReturerDB" and test02 is "6" as was expected, or at least wanted. What am I doing wrong?
You can do this:
var groupedData = db2.ReturerDB.GroupBy(r => new { r.Date.Year, r.Date.Month })
.Select(g => new { g.Key.Year, g.Key.Month, Count = g.Count() })
.OrderBy(x => x.Year).ThenBy(x => x.Month);
.ToList();
var result = groupedData
.ToDictionary(g => string.Format("{0}-{1:00}", g.Year, g.Month),
g => g.Count);
Which will give you
Key Value
---------------
2013-11 5
2013-12 10
2014-01 3
(Creating a dictionary is slightly easier than a two-dimensional array)
This will work against a SQL back-end like entity framework of linq-to-sql, because the expressions r.Date.Year and r.Date.Month can be translated into SQL.
with a nod to mehrandvd, here is how you'd achieve this using linq method chain approach:
var dateRange = { // your base collection with the dates};
// make sure you change MyDateField to match your won datetime field
var groupedData = dateRange
.GroupBy(dateRow => dateRow.MyDateField.ToString("yyyy-mm"))
.OrderBy(monthGroup => monthGroup.Key)
.Select(monthGroup => new
{
Month = monthGroup.Key,
MountCount = monthGroup.Count()
});
This would give you the results you required, as per the OP.
[edit] - as requested, example of how to access the newly created anonymous type:
foreach (var item in groupedData)
{
Console.WriteLine(item.Month);
Console.WriteLine(item.MountCount);
}
OR, you could return the whole caboodle as a jsonresult to your client app and iterate inside that, i.e the final line of your view would be:
return Json(groupedData, JsonRequestBehavior.AllowGet);
hope this clarifies.
What you need is grouping.
Considering you have a list of dates a solution would be this:
var dateRows = // Get from database
var monthlyRows = from dateRow in dateRows
group dateRow by dateRow.ToString("yyyy/mm") into monthGroup
orderby monthGroup.Key
select new { Month=monthGroup.Key, MountCount=monthGroup.Count };
// Your results would be a list of objects which have `Month` and `MonthCount` properties.
// {Month="2014/01", MonthCount=24}
// {Month="2014/02", MonthCount=28}
I have a linq query in which I need to be able to select an variable number of fields from a datatable. I do know all of the fields that could be included, but only two will for sure be in the datatable. I also will know which fields are included in the datatable (it will just be different depending on the user's selections). Right now I set up something like this:
var query = from item in dt.AsEnumerable()
group item by item.Field<string>("ID") into g
select new
{
ID = g.Key, //required
Status = g.Min(i => dostuff(i,"Status")), //not required
Disc = g.Min(i => dostuff(i,"Disc")), //not required
Loc = String.Join<string>(",", from i in g select i.Field<string>("Loc")) //required
};
dostuff(DataRow i,string field)
{
try
{
return i.Field<string>(field);
}
catch
{
return null;
}
}
So dostuff basically is just checking whether or not that field exists in the dataset, and then I would just need to ignore the non-existant fields when working with the query results, which would not be too difficult. However, it seems like there is probably a better way to do this, but I've had a tough time finding anything via Google about using a dynamic select clause.
You could do it with dynamic type (nb, I did not test so this might have typos.):
var query =dt.AsEnumerable().GroupBy(item => item.Field<string>("ID"))
.Select(g => {
dynamic t = new System.Dynamic.ExpandoObject();
if (g.Table.Columns.Any(c => c.ColumnName == "Status"))
t.Status = g.Field<string>("Status");
if (g.Table.Columns.Any(c => c.ColumnName == "Disc"))
t.Disc = g.Field<string>("Disc");
t.ID = g.Key;
t.Loc = String.Join<string>(",",g.Select(i => i.Field<string>("Loc")));
return t;
}
I have a linq query that works when it I had a list of a single value now that I change to having a List that has several properties I need to change the where clause
So this works:
List<string> etchList = new List<string>();
etchList.Add("24");
var etchVect = (from vio in AddPlas
where etchList.Any(v => vio.Key.Formatted.Equals(v))
let firstOrDefault = vio.Shapes.FirstOrDefault()
where firstOrDefault != null
select new
{
EtchVectors = firstOrDefault.Formatted
}).ToList();
However I have a new hard coded list (which will represent incoming data:
List<ExcelViolations> excelViolations = new List<ExcelViolations>();
excelViolations.Add(new ExcelViolations
{
VioID = 24,
RuleType = "SPACING",
VioType = "Line-Line",
XCoordinate = 6132,
YCoordinate = 10031.46
});
So the NEW Linq query looks like this, but is obviously will not work as
AddPlas is a List and so using this other list of excelviolations, I wish to have it do where on each one of the properties in the excelviolations list
var etchVect = (from vio in AddPlas
where excelViolations.Any(vioId => vio.Key.Formatted.Equals(vioId))
let firstOrDefault = vio.Shapes.FirstOrDefault()
select new
{
EtchVectors = firstOrDefault.Formatted
}).ToList();
Now, since this is a list within a list, I would like to do something like add in each of the properties
so for example:
where excelViolations.VioID.Any(vioId => vio.Key.Formatted.Equals(vioId))
However that is not possible, but you see that I'm trying to access the property of VioID that is in the excelViolations and match it to the Key which is in vio list
Just change this line
where excelViolations.Any(vioId => vio.Key.Formatted.Equals(vioId))
to
where excelViolations.Any(excelVio => vio.Key.Formatted.Equals(excelVio.VioID))
then i thought it will works