Search results matching tag 'Linq'

Exception in Linq query

chintanpshah — Tue, 08 Dec 2009 05:00:00 GMT

i am using linq and i am getting a result from

var query = from c in db.tempEmployees
join o in db.tempDepartments on c.DepartmentID equals o.DepartmentID
join de in db.tempEmployee_Departments on new { o.DepartmentID, c.EmployeeID } equals new { de.DepartmentID, de.EmployeeID }
where FNames.Contains(c.FName)   
select new
{
	c.EmployeeID,
	c.FName,
	c.LName,
	c.BirthDate,
	c.DepartmentID,
	c.Email,
	c.Created_UserID,
	c.Gender,
	c.LC_TS,
	c.LC_Userid,
	c.Weight,
	o.Name,
	de.Salary,
	de.Created_TS
};

foreach (var result in query)
{
	//TO DO..
}

Whenever query does not returns rows, exception occurs.
How to handle it?

Dynamic Aggregating columns using linq

mrp123 — Sat, 05 Dec 2009 05:00:00 GMT

I have a datatable like below, the Sales team can have any numbers (in the below example only two columns sales1and sales2)

FactoryName   MachineName   StartTime       Sales1   Sales2
Fact 1           M1   2009-11-06T00:00:00+05:30   1   2
Fact 1           M2   2009-11-06T00:00:00+05:30   1   2
Fact 2           M1   2009-11-06T00:00:00+05:30   5   6
Fact 2           M2   2009-11-06T00:00:00+05:30   7   7
Fact 2           M3   2009-11-06T00:00:00+05:30   8   8
Fact 1           M1   2009-11-07T00:00:00+05:30   9   9
Fact 1           M2   2009-11-07T00:00:00+05:30   10   100
Fact 2           M1   2009-11-07T00:00:00+05:30   15   1
Fact 2           M2   2009-11-07T00:00:00+05:30   12   2
Fact 2           M3   2009-11-07T00:00:00+05:30   16   3

I want to write a linq query which should return me like below ,for each factoryname,day I need the sum of sales1 and sales2 ( this sales 1 and sale2 is not static columns this can be any noumber of columns) ,basically I need help for achieving this using dynamic linq

FactoryName   StartTime                  Sales1 Sales2
Fact1           2009-11-06T00:00:00+05:30   2   4
Fact2           2009-11-06T00:00:00+05:30   20   21
Fact1           2009-11-06T00:00:00+05:30   19   109
Fact2           2009-11-06T00:00:00+05:30   43   6

var MyQuery = (from table in myDataset.Tables[0].AsEnumerable()
                                  orderby table["StartTime"]
                                  group table by new { FactoryName = table["FactoryName"], StartTime = table["StartTime"] }
                                      into myGroupedTable
                                      select new
                                      {
                                          FactoryName = myGroupedTable.Key.FactoryName,
                                          StartTime = myGroupedTable.Key.StartTime,
                                          sales1 = myGroupedTable.Sum(table => table.Field<Double?>("sales1")),
                      sales2 = myGroupedTable.Sum(table => table.Field<Double?>("sales2"))
                                      });

the above query returns me the data which I want ,but my problem is in the dataset (myDataset.Tables[0]) I may have any number of columns for sales ( like sales1,sales2,sales3 ,sales4 etc...) I need the sum of all those sales columns independently .How can I do that ? please help me with some code snippet

How to query an xml document having xmlns prefixes by Linq?

arefkarimi — Wed, 02 Dec 2009 05:00:00 GMT

Hi gurus,

I have created a Workflow application in MOSS 2007. In the workflow code I get the Initiation Data as an xml. Like the one bellow:

// 0) fix(e,"cb");} if (e.className=="di"){if (e.children(0).innerText.indexOf("\n")>0) fix(e,"db");} e.id=""; } function fix(e,cl){ e.className=cl; e.style.display="block"; j=e.parentElement.children(0); j.className="c"; k=j.children(0); k.style.visibility="visible"; k.href="#"; } function ch(e){ mark=e.children(0).children(0); if (mark.innerText=="+"){ mark.innerText="-"; for (var i=1;i

- <my:Main xml:lang="en-US" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD/2009-11-30T11:01:02" xmlns:xd="http://schemas.microsoft.com/office/infopath/2003">

<my:MyManager>office\aref</my:MyManager>

</my:Main>

As you see. there is a "my" prefix at the begining of each element. That thing prevents me from querying the xml in order to find the value of MyManager element. I try to get the value by this code:

private string GetMyManager(string initiationData)
        {
            XmlTextReader reader = new XmlTextReader(new StringReader(initiationData));
            XDocument doc = XDocument.Load(reader);
            return doc.Elements().First().Element("MyManager").Value;
        }

both .Element("MyManager") and .Element("My:Manager") throw exception.

Thanks for any help in advance

Re: Programmatically set value of LINQ where parameter?

mkamoski — Tue, 01 Dec 2009 05:00:00 GMT

I am sorry that I do not have a specific answer.

However, you should look at this...

http://code.google.com/p/coolite-mvc/source/browse/trunk/Coolite.Toolkit.MVC/Code/DynamicLibrary.cs?spec=svn20&r=

...which is a really nice DynamicLibrary that allows one to write dynamic where statements with Linq.

I have a full working sample here...

http://mkamoski1.wordpress.com/2009/12/01/t4-t4-toolbox-linq-to-sql-entity-base-code-sample/

...which you are free to check out, etc.

HTH.

Thank you.

-- Mark Kamoski

LINQ data retriving behavior

Aravind00kumar — Mon, 30 Nov 2009 05:00:00 GMT

Hi,

I need a small help in understanding LINQ behavior.

In database there is a table as follows

[USERINFO]- Table name

USERNAME	PASSWORD	EMAIL	SECQUESTION	SECANSWER	STATUS
Smith	Smithpw	smith@hotmail.com	A	B	True
John	Johnpw	john@gmail.com	AA	BB	False
Jackman	Jackmanpw	jm@gs.com	AB	BA	True
Joseph	Josephpw	jp@tenon.com	ABA	BAB	True

Stored procedures as follows
CREARE GetAll Users

SELECT * FROM USERINFO

I wrote a LINQ query as follows. (I want only user name)

Public List<string> GetAllUsernames()

{

List<string> unames = new List<string>();

MyDBDataContext mdx = new MyDBDataConext();

var x = from temp in mdx.GetAllUsers() select (string) temp.USERID;

foreach (string xt in x)

{

unames.Add(xt);

}

Return unames;

}

So far everything is ok; my question is I need only the names of the users who are in the [USERINFO] table. To retrieve this data I called the stored procedure GetAllUsers(), even I got the correct answer. But only to retrieve the username executing ‘GelAllUsers’ procedure is correct?. Because that procedure is returning the USERINFO table’s all the fields rather than usernames. So I think it may cause to performance down/security threat.

So I want to know how the LINQ involves in execution of this model…

Please explain in detail that I can’t go wrong with LINQ.

I know one solution that is write one more procedure that returns only username

SELECT USERNAME FROM USERINFO

But if I do like this, then what is the specialty of LINQ,

I don’t think so that it is the replacement or advanced behavior to get the data from database without writing SqlConnection cn = new SQLConnection(st).. and etc…

To overcome this headache “Microsoft Enterprise Library” is already there in the market.

So why LINQ..?

Even I know one feature that is LINQ can retrieve (Query string) data in the similar way from XML, DataBase, Generic Objects… I don’t think it is only the great feature to use LINQ.

Don’t suggest me to read ebooks kind of things because I didn’t found solution in any book

Question 2:

How to call procedure that Insert data into database..??

Thanks& Regards,

Aravind Kumar | Aravindkumarmail@gmail.com

LINQ help for select functions

aspcheetah — Sat, 28 Nov 2009 05:00:00 GMT

Hi,

Currently I have the following functions. As you can see subroutines are identical except for the Where clause.

Is there a way to assign this where clause dynamically and avoid creating separate methods?

 The main issue is how to get myissue.useremail or any other property passed in dynamically? Is there a way to assign such a statement to a variable?

 Private Sub EmailSearch()
        Dim myDBML As New DataClassesDataContext()
        Dim myIssues = From myIssue In myDBML.issues _
                       Where myIssue.useremail = textbox1.Value _
                       Select myIssue.subject
        BindGrid(myIssues)


    End Sub

    Private Sub DateSearch()
        Dim myDBML As New DataClassesDataContext()
        Dim myIssues = From myIssue In myDBML.issues _
                       Where myIssue.mydate = textbox1.Value _
                       Select myIssue.subject
        BindGrid(myIssues)


    End Sub


    Private Sub TicketSearch()
        Dim myDBML As New DataClassesDataContext()
        Try
            Dim myIssues = From myIssue In myDBML.issues _
                       Where myIssue.cid = Convert.ToInt64(textbox1.Value) _
                       Select myIssue.subject
            BindGrid(myIssues)

        Catch ex As Exception
            label1.Text = ex.Message

        End Try
        

    End Sub

LINQ database model to SQL diagram?

SkykeN — Thu, 26 Nov 2009 05:00:00 GMT

Hallo, I took over a project from someone and I have to change the database (add columns, add associations,...).

Now when I work with linq I make an SQL diagram in SQL first and then make the linq database model so when I change something I just delete the model and let VS automaticly generate a new one with the modifications.

But this guy made all connections and so in the LINQ DBML itself so when I delete it and add it again all connections are gone.

Is there a solution for this? Something that converts the LINQ DBML to an SQL diagram. Because else I will have the make the diagram all over again in SQL and it's a BIG database...

Re: textbox subtotal

aquaren — Tue, 24 Nov 2009 05:00:00 GMT

Here is one way to do it.

        Function CalculateSubtotal(ByVal values As IList(Of String)) As Double

            Return values.Sum(Function(x) CDbl(x))

        End Function

        Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click

            Dim values As IList(Of String) = New List(Of String)
            Dim profit As Double

            values.Add(TextBox1.Text)
            values.Add(TextBox2.Text)
            values.Add(TextBox3.Text)
            values.Add(TextBox4.Text)
            values.Add(TextBox5.Text)

            profit = CalculateSubtotal(values)

        End Sub

This way you can just add the textboxes you want to the values list for subtotaling, and you only have to do the value conversion once in the CalculateSubtotal method

Re: how to make linq query a class property ?

ali62b — Tue, 24 Nov 2009 05:00:00 GMT

instead of T write the class name of the returned object from query.

Movie , Person , ....

or if it not exists in your model ,create a class that has the properties of the returned object and use that instead of T .

hope this helps.

Re: Deleting a record including related records in LINQ

jclark434175 — Mon, 16 Nov 2009 05:00:00 GMT

Hey I wrote a blog post about how to perform deletes with LINQ. Check out my blogpost and if you still have some questions feel free to post your issue.

http://joshua-clark.blogspot.com/2008/05/how-to-perform-deletes-with-linq-to-sql.html

Hope this helps