ADO.NET :: Possible To Generate Dynamic LINQ Statement?
Nov 29, 2010
Is it possible to generate dynamic LINQ statements? I need to be able to build conditional "WHERE" clauses for some of my LINQ statements. I don't want to write a giant block of code to hand every possible combination of filters, sorts and groups. I found a article online that outlines how to use string based where clauses here. Does LINQ in framework 4.0 no longer support this? Every example I've found has giant walls of virtually unreadable, must likely unmaintainable code.
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Nov 25, 2010
I have a page with filters and accordingly to what the user selects, it has to generate a query. I'm using this code:
[code]....
However Linq-To-Sharepoint doesn't convert most of this to CAML and the list I'm querying has more than 50000 items. It takes about 4-8 seconds to retrieve the items which is not acceptable.
I've been trying to generate a dynamic query but so far I haven't been able to get it to work.
With AND and OR operations to generate the query I could put all those conditions on code and increase performance.
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Mar 5, 2010
I am having trouble with this I have 3 Data tables i use over and over again which are cached I would like to write a LINQ statement which would do the following is this possible?
T-SQL VERSION:
SELECT P.[CID],P.[AID]
,B.[AID], B.[Data], B.[Status], B.[Language]
FROM MY_TABLE_1 P
JOIN
(
SELECT A.[AID], A.[Data], A.[Status], A.[Language] FROM MY_TABLE_2 A
UNION ALL
SELECT B.[AID], B.[Data], B.[Status], B.[Language] FROM MY_TABLE_3 B
) B on P.[AID] = B.[AID]
WHERE B.[Language] = 'EN' OR B.[Language] = 'ANY' AND B.STATUS = 1 AND B.[Language] = 'EN' OR B.[Language] = 'ANY' AND B.STATUS = 1
Then i would like it to create a result set of the following
Results:
|CID|AID|DATA|STATUS|LANGUAGE
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Apr 20, 2010
I've added the Dynamic.cs file to my project and have set it's Build Action = Compile in order to get the System.Linq.Dynamic namespace.
However, when I try to use any of the new code I am getting an ambiguous call error; see below.
[Code]....
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Feb 11, 2011
I want to use "if statement" in Linq query. How can I do this situation?
For example:
if txtAge.Text=="", I will not use that in Linq Query.
else txtAge.Text!="", I will use that in Linq Query.
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Dec 13, 2010
I have a sp that generates a result looks like below
Userid orgid
1 100
1 200
1 400
2 100
I would like to generate a string something like below by looping thru the output result data table using ado.netUserid 1 should generate It needs to generate below statement surround by {} and separated by comma(,) if it has multiple orgids.. and orgid( after & ) need to be dynamically assigned in the string based on the table..
{[Org].[org ID].&[100], [Org].[org ID].&[200] ,[Org].[org ID].&[400] }
Userid =2
{[Org].[org ID].&[100] }
How can I dynamically generate this statement? I can generate the stament if there is only one orgid for user but if you have multiple orgs .. not sure how Ic an concatenate multiple orgids by comma..
AllowedSet = "{[Client].[Client ID].&[" + ClientID +
"]}";
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May 4, 2010
in generate the Stored Procedures when using Create TableAdapter configuration Wizard in VS.it can not generate the Stored Procedures for Delete and Update Commands, but it generated for Select and Insert. i tried many times, but still get the same problem.
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Dec 24, 2010
We would like to perform something like this
string strCondition = "FirstName=='abc'"
from p in People.Where(strCondition) select p
In our architecture we are usign both Linq-Sql as well Linq-Entity. So please give some thoughts wehter it is possible or not and is there any way to perform this?
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Sep 29, 2010
Is this LINQ statment vulnerable to SQL injection?
var result = from b in context.tests
where b.id == inputTextBox.Text
select b;
where context is an Entity and tests is a table. I'm trying to learn LINQ and I thought that the benefit of it was that it wasn't vulnerable to sql injection, but some stuff I've see has said differently. Would I need to parametrize this LINQ statement to make it safer? If so, How? Also would this be considered linq to sql or linq to entities?
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Mar 23, 2011
I am new to LINQ. I have a GridView which I am populating using LINQ. My LINQ statement is taking query string from previous page. The query string is in string format. Here is the code:
protected void Page_Load(object sender, EventArgs e)
{
string getEntity = Request.QueryString["EntityID"];
[code]...
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Mar 5, 2010
I am trying to have the collection of order IDs be used in my where statement how come i can't get this to work?
List<int> orders = new List<int>(){1,2,3,4,5};
DataTable dtTable1 = getOrders();
DataTable dtTable2 = getOrderDetails();
var results = from a in dtTable1.AsEnumerable()
join b in dtTable2.AsEnumerable() on a.Field<int>("ID") equals b.Field<int>("ID")
where orders.Contains(b.Field<int>("OrderID"))
select a;
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Mar 4, 2011
have following method which returns "List"
public List<DistributionGroup> GetDistributionGroupsByUserId(Guid userId)
{
return (from dgu in db.DistributionGroup_Users where dgu.UserId == userId select
[code]...
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Mar 23, 2011
I have a GridView which is not bound to any DataSource. In my page load event I am writing this code:
protected void Page_Load(object sender, EventArgs e)
{
string getEntity = Request.QueryString["EntityID"];
int getIntEntity = Int16.Parse(getEntity);
[Code]....
Now I can see the the value is coming from previous page, but my GridView is not populating anything. What I am doing wrong here?
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Nov 27, 2010
OK So I know WHY I am having the error I am getting. I don't know HOW to fix it. Basically, if the user doesn't have a certain permission, I need to join another table. But .NET is so picky I can't just make two different queries in an IF statement and then use it outside of the if statement. I can think of some ugly work arounds for this, but I would rather not. I am fairly new to .NET I know just enough to be dangerous.
[code]....
I get the error: Unable to cast object of type
'System.Data.Linq.DataQuery1[VB$AnonymousType_111[System.Guid,System.String,System.String,System.String,System.String,System.Nullable1[System.DateTime],System.Nullable1[System.DateTime],System.Nullable1[System.Guid],System.Nullable1[System.DateTime],System.Nullable1[System.Guid],System.Nullable1[System.DateTime]]]' to type 'System.Collections.Generic.IEnumerable`1[Ten11CRMLib.Company]'.
because of this: Dim l As IEnumerable(Of Company) its not just IEnumerable of a Company, its got the source in it. I have to explicitly select source to use it in my datagrid. Can I make Dim l something that will make it stop complaining?
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Jan 18, 2011
[Code]....
[Code]....
creating Linq query in return statement
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Apr 5, 2010
[Code]....
I must have a LINQ Statement does i can show if my Time in the DB <= as the Time where i become from my Session +60 Minutes ??
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Jun 22, 2010
I have a method to execute two "Update" sql statements.
The first one works fine and the second one I can't get to work for nothing.
Here is the entire method:
[Code]....
The error I am getting is "Incorrect syntax near '05'."
It is occuring on the next to the last line which is:
dc.ExecuteCommand(sql);
I update the variable "sql" first so I can debug. At the time it crashes the value of sql is:
"Update Blogs set Status = 'Archived', ArchiveDate = 06/22/2010 05:14:46 PM Where (BlogID != 1) and (Status = 'Published') and (AuthorID = 9e37e028-c205-4903-920e-e8643b30a724)"
It appears to be the ArchiveDate that is causing the problem here. The "05" is the hour of the time portion. Both ArcgiveDate and PublishDate are defined exactly the same in the database. If you look at the first dc.ExecuteCommand it does exactly the same
thing with PublishDate (DateTime column) in the same table and it works just fine.
Then I modifed the code and remove the ArchiveDate from the sql statement then I get the error:
"Incorrect syntax near 'e028'."
which as you can see is part of the AuthorIDs value in the where clause. So I am assuming both the date and the Guid / Author ID is causing problems. I have tried enclosing the values in quotes but I just cant make this work even though it seems to be working fine in other places.
I even remove the code for the author ID and left in the code for the ArchiveDate and it still does not work so I have proved that both are causing a problem.
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Aug 18, 2010
My application includes BUILDING table with columns BUILDING_ID, NAME, TOWN_ID, I run the LINQ query listed below and need to append two letters to buildings.NAME based on TOWN_ID. I assume that I need to place an "if" or "select" statement inside the query but I can not figure out how to do that,
[Code]....
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Mar 26, 2010
I am trying to insert a new account in my Acccounts table with linq. I tried using the EntityModel and Linq2Sql. I get no insert into my database nor an exception of any kind.
public static Linq2SQLDataContext dataContext {
get { return new Linq2SQLDataContext(); }
}
[code]...
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Mar 12, 2011
Right now I have an error if f.ParentID is null:
DataSet1.TreeItemRow[]
TreeItemRows = (from f
in tidt
where (f.ParentID == TreeItemId)
select f).ToArray();
I must continue if f.ParentID is null, I don't want to include null fileds in the array. What is the right syntax for that is linq sql?
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Sep 1, 2010
creating a dynamic select statement, so far my SP look like below
[code]....
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May 25, 2010
I am using Linq to SQL. Tables have timestamp columns and I am using regular Linq methodology in ASP.NET MVC.I do use detached entities and always try to do updates without first querying the database for the original entity. To update an entity I use context.Attach(entity, true) followed by context.SubmitChanges() and all is fine. The sql statement that gets executed looks like:
[Code]...
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Dec 15, 2010
Using linq to entities i am connecting to a database, the database has tables in it that has payments that have a multi to multi relationship with jobs. This is acheived via an allocs table. I want a list box with all the jobs that has a column called due price which takes all of the allocations of payments for this job and takes that away from the job price. However, using the below linq to entities statement. The problem is that if the job has no allocations it returns null and therefore the due payment is empty. What i really want is for the due payment to be the job price if there are no allocations however, i cannot think of a way around this.
var jobs = from j in data.jobs
where j.property.customer.id == customerid
&& j.completed != null
select new
{
j.id,
j.price,
dueprice = j.price - ( from a in data.allocs
where a.job.id == j.id
select a.amount ).Sum(),
lineone = j.property.lineone,
postcode = j.property.postcode,
jobtype = j.jobtype.name,
j.completed
};
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Aug 8, 2010
I have the following statement:
List<string> tracks = new List<string> { "ABC", "DEF" };
var items = (from i in Agenda.AgendaSessions
select i).Where(p => p.Tracks.Any(s => tracks.Contains(s.Code)));
this returns all sessions which track contains either ABC or DEF, now when I rewrite the statement like the following, it returns All sessions regardless, as if the clause always yeilds into true,
var items = from i in Agenda.AgendaSessions
where i.Tracks.Any(s=> tracks.Contains(s.Code))
select i;
Update
if there are other clauses within the where, does that affect the results?
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Aug 2, 2010
when I click 'create new site' link/button it will redirect me to some page and ask me some questions related to that site which I am about to create .. At the moment it display me question and for input their respective control like to choosing category it display me drop down list ... for business name textbox is displayed. and so on ...
So my question is how can I do the same task ? that is what ever the question is their respective control is displayed for getting information ..
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