LINQ To SQL
Apr 20, 2008Is it possible to use LINQ to SQL with Report Services? If so, are there any examples, tutorials, etc.?
View 1 Replies
ADVERTISEMENT
Max With LINQ
Jan 8, 2008Hello!
I try to get a list of ConditionsVersion where Version is MAX for each ConditionsVersion.
I tried something like this (as seen on http://msdn2.microsoft.com/en-us/vcsharp/aa336747.aspx#maxGrouped):
1 List<ConditionsVersion> list = (from cv in ConditionsVersions2 group cv by cv.FKConditions into cv3 select new { 4 PKConditions = cv.PKConditions,5 FKConditions = cv.FKConditions,6 MaxVersion = cv.GroupBy.Max(cv => cv.Version)7 CTimestamp = cv.Timestamp8 }).ToList();
But it doesn't work. It would be great if someone knows why.
Thank you!
LINQ - What Do You THINK?
Nov 2, 2007Well, just played a little bit with that new thing from Microsoft. Genius! Microsoft presented that step backwards as a step forward.
Say good bye to the 3-tier architecture, now any programmer, after 1 week training, will be able to put SELECT * into the source code. No more stored procedures and logic on a server. No more ugly WHERE clauses. Just SELECT * and pass all records in a loop :)
When I looked at the queries, generated by LINQ in SQL profiler, I noticed that they are generated automatically using the same pattern. It is obvious, of course, but now it would be really difficult to trace a problematic query back to the C# code. All updates to table X will look like as identical twins!
On the other side, it is not so bad. We will have soon a lot of projects, failing when they go to the production and face the real volumes of data. And a long queue of companies, crying and asking to save them. Perfect “job security�. Please, use LINQ! Port all your code to LINQ immediately (Laughing demonically like Dr. Evil)
Hm… a second thought, but what could we suggest to these companies, having performance problems with LINQ 3rd party applications, when there is no source code? Now we could at least modify some stored procedures, and with LINQ looks like the only recommendation could be “contact a developer of that application or buy more a powerful server�.
Linq To Sql
May 28, 2008 Is Linq a feature of sql server 2008 ?
Or is it a feature of DOt net. Visual Studio 2008 ?
Linq To Sql
May 28, 2008Some say linq to sql leads to the death of stored procedures is it correct ?
View 4 Replies View RelatedLinq + Sql Server Everywhere = ?
Nov 8, 2006Will Linq be compatible with Sql Server Everywhere without having to add additional plugins?
View 7 Replies View RelatedLINQ To SQL Question ?
Dec 30, 2007Hullo am using Asp.Net 3.5, I want to create a usercontrol that is supported to all projects to upload file into sqlserver,
the user just give the database connection string,
tablename, column name depending upon their need, here I develop the
code using LINQ technology.
I Write a class with simple format like below,
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.Linq;
/// <summary>
/// Summary description for FILE_MASTER_INSERT
/// </summary>
//namespace Linq2Sql_demo_doc
//{
[System.Data.Linq.Mapping.Table(Name = "FILE_MASTER")]
public partial class FILE_MASTER
{
string Tablename;
public FILE_MASTER()
{
//
// TODO: Add constructor logic here
//
}
[System.Data.Linq.Mapping.Column(Name="filename")]
public string FileName
{
get;
set;
}
[System.Data.Linq.Mapping.Column(Name = "file_content")]
public byte[] file_content
{
get;
set;
}
[System.Data.Linq.Mapping.Column(Name = "file_id", IsPrimaryKey = true, IsDbGenerated = true, CanBeNull = false)]
public int file_id
{
get;
set;
}
}
public class TestDB : DataContext
{
public Table<FILE_MASTER> FILE_MASTERs;
//Initializing base class constructor
public TestDB(string s) : base(s) { }
}
This
is working but, this is suitable only for single table, I expect
depending upon the user input automaticaly the tablename, column name
will change in the yellow block codes .
Is there any way to update the tablename , columnname from any other class?
Thank you. Jeyaseelan
When IDENTITY_INSERT Is Set To OFF. -- LINQ
Jan 21, 2008I'm new to ASP/VS/Linq and I'm having a small problem.
I have one table setup in SQL Server Express 2005 through Visual Studio 2008. The table name is "Users" and has three columns (accountID, userName, email). AccountID is the primary key and set to auto incriment. I've added a couple of records by hand and it works.
I have a single form with a button, a label, and two text boxes. The button code is below. After entering some fake data that does not already exist in the database and clicking the button I get this.
Cannot insert explicit value for identity column in table 'Users' when IDENTITY_INSERT is set to OFF.
I understand that it is trying to insert something into the accountID field but I don't understand why since I'm only providing a username and e-mail address to insert.
Your help is greatly appreciated.protected void Button1_Click(object sender, EventArgs e)
{
MyDatabaseDataContext db = new MyDatabaseDataContext();
var query = from u in db.Users
where u.email == txtEmail.Text
select u;
var count = query.Count();
if (count == 0)
{
//Create a new user object.
User newUser = new User();
newUser.username = txtUsername.Text;
newUser.email = txtEmail.Text;
//Add the user to the User table.
db.Users.InsertOnSubmit(newUser);
db.SubmitChanges();
}
else
{
Label1.Text = txtEmail.Text + " already exists in the database.";
}
Linq ISingleResult
Jan 27, 2008I have a supplier table with all my suppliers in it. I list them in a gridview. In this gridview, there is a link next to each record to an edit page. Below is the code for the edit page. Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim db As New orderLinqDataContext
Dim q = db.selectSupplierByID(Request.QueryString("id"))
Dim r As New System.Data.DataTable
txtFriend.Text = q(0).friendlyName
txtAdd1.Text = q(0).address1
txtAdd2.Text = q(0).address2
txtAdd3.Text = q(0).address3
txtAdd4.Text = q(0).address4
txtName.Text = q(0).supplierName
txtPhone.Text = q(0).phone
txtFax.Text = q(0).fax
txtPostCode.Text = q(0).postCode
End Sub
This causes a runtime error. The error is: "The query results cannot be enumerated more than once." and the txtAdd1.text line is highlighted.
How am I supposed to get at the data so I can fill my text boxes this way?
Thanks,
How To Do Where In Select In Linq?
Mar 7, 2008var query = from cloc in context.t_companylocs where (cloc.ref_company == companyid) && (cloc.street == attributes["Street"]) && (cloc.postalcode == attributes["Postalcode"]) && (cloc.country in countrylist) && (cloc.city in citylist) select cloc; attributes is a Dictionary<string, string> object.countrylist and citylist are List<string> objects.Of course the syntax above doesn't work. It's basically what I'm trying to achieve :-)A quick and dirty solution would be to just drop the two where constraints containing the "where in" statement and handle that part in the following foreach() loop.Can anyone please explain how you would do it properly?regards
View 1 Replies View RelatedLinq To Sql -- Inserting
Mar 12, 2008Does anyone have a good example of how to insert data using System.Data.Linq? All the examples I've seen do something likeNorthwindDataContext db = new NorthwindDataContext();var x = new Product() {...}; db.Products.Add(x);db.SubmitChanges(); However I'm not seeing an Add method on System.Data.Linq.Table<T>. Has this changed? Could I somehow not be generating my model correctly?
View 2 Replies View RelatedLinq To Sql Autogenerated Value
Mar 20, 2008Hello,
How can I get autogenerated value of inserted item with linq to sql?
Thanks
LINQ To SQL Using CONTAINS Or CONTAINSTABLE Possible?
May 12, 2008I would like to use LINQ to generate a sql statement that does not use LIKE, but rather uses CONTAINS. Is this possible? If not, my second question is whether or not I can parameterize a SqlCommand that uses CONTAINS. For example the following statement works just fine when I pass in the parameter via SqlCommand.Parameters.AddWithValue()SELECT * FROM [event] WHERE CONTAINS(comments, @searchTerm1)However, the following results in a variable not defined error.SELECT * FROM [event] WHERE (comments LIKE @searchTerm1)Any ideas? Thanks for your help.
View 1 Replies View RelatedLinq-to-SQL And ASP:Repeater
May 25, 2008Hi there,
In 2005.NET, if I used an asp:repeater, I would load the data from source and then manipulate it like so://load the data from source using a predefined connection and SQL Statement.private void LoadMyDataFromSource(){ try { connection.Open(); OleDbDataReader myReader = comm.ExecuteReader(); rptrCatList.DataSource = myReader; rptrCatList.DataBind(); myReader.Close(); } finally { connection.Close(); }} //catch the ItemDataBound event and manipulate the data how I wish before it's loaded into the Repeater.protected void rptrCatList_ItemDataBound(object sender, RepeaterItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { int title = 4; //this is the index of the column I wish to manipulate((Label)e.Item.FindControl("lblTitle")).Text = ((IDataRecord)e.Item.DataItem).GetString(title) + ":" } }This would give me all the flexbility I ever needed. But now I wish to use linq and since the IDataRecord relies on dataReader sources, I cannot obtain the same flexbility. Can anyone point me in the right direction for obtaining the same kind of flexbility but using a linq-to-SQL dataContext? I wish to manipulate mostData that comes through from my source, so: //loadng the data in via my linq-to-sql context.private void LoadProducts() { MyDataContext db = new MyDataContext (); var all = from p in db.Products_IncontinenceStandards where p.Product_Cat == "Category1" select p; rpterCat.DataSource = all; rpterCat.DataBind(); }This is where I get stuck because, even though I can still capture the ItemDataBound event since I have databound the Repeater to the linqSource, I can't access the individual fields (or this is what I think I can't do!), Does anyone know how to relate to this so I can create the same effect? Many Thanks,Nathan Channon
SSIS Or LINQ
Apr 24, 2008Hi,
I am beginner in SQL Server So excuse me if my question is stange for you.
I have to work on an sql server 2005. I need to extract data from this server in XML file. I have look at a lots of thing and I find two solutions:
- Use SSIS
- Create a home made solution with LINQ in c#
Clearly I do not have enouth experience to see with solution are the most available? Which are the things required to use those solutions?
Thanks
Left Join Using Vb 9.0 And LINQ
Dec 2, 2007Hi Guys,
I started working with linq and vb9.0 but i have a small problem i could feagure how to solve in c# but not in vb
I wanted to make left join or right join on vb 9.0 and linq is it possible or this is only c# feature ?
Waiting to hear from u guys,
Thanks
Softy
Add Multimple Data Using LINQ
Dec 30, 2007Hello, How do I add multiple data using LINQ, this one doesn't work. ... Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click Dim i As Integer For i = 0 To 3 Dim db As personalDataContext = New personalDataContext Dim p As personal = New personal p.name = "John" p.number = "01213" p.picture = "image/image.jpg" db.personals.InsertOnSubmit(p) Next End Sub... cheers,imperialx
View 1 Replies View RelatedMultiple Where Predicates In Linq?
Jan 7, 2008I'm just starting to dabble around with LINQ and all of the examples I've come across all have 1 where clause. Is this intentional such that we are supposed to build queries on top of queries or is there a method in which I can add multiple predicates to my 1 query? I'm sorry if this sounds like a stupid question, I've been googling it to death and reading the few manuals on LINQ but like I said, all of the examples have had 1 where predicate.
Thanks,
Chance
Annoying Problem With LINQ To SQL
May 3, 2008hi, i'm working with LINQ to SQL and i have a table called Account, in that is Type, which is an int in the database but i map it to a AccountType enum, this works fine, but if i go into the dbml designer and change something later on, it gets errors, so i have to change all int->enum mappings back to int, recompile and then set them again! has anyone else had this? kindest regards
View 5 Replies View RelatedSorting By A Numeric In LINQ
May 15, 2008Here's my LINQ code:pl = (from p in db.Table where p.ID == 1 orderby p.NumericField descending select p).Take(7);
As you can see, I'm trying to sort by a numeric field. Specifically, it's a Numeric(5,0) field.
Problem is, the results aren't coming back numeric order. If this is good LINQ code, perhaps it's something else in my app. I just want to make sure this LINQ code is good.
Thanks in advance
Accessing StoredProcedure From LINQ
Jun 2, 2008Can I know the best method to connect the sql server 2008 with Visual studio 2008, it will be helpful if I know how to access the stored procedures in the sqlserver via LINQ.
View 1 Replies View RelatedLinq Joining A Table On Itself?
Oct 1, 2013I am trying to convert the following sql to linq
SELECT R.UserID,R.Cntrl_nbr FROM User R
WHERE (
R.REG_ID=
(SELECT MAX(B.REG_ID)
FROM User B
WHERE R.UserID = B.UserID )
The linq I am using is
var query = (from n2 in q1
where
n2.RegServiceTs == (q1.Where(c1 => c1.UserID == n2.UserID).Max(c2 => c2.REG_ID))
select n2).SingleOrDefault();
This is slow and is there a better way to do this?
CLR Triggers, Linq, And Transactions
Aug 14, 2007I'm trying convert my working CLR Trigger to a Linq-based implementation, but I don't seem to be able to get Linq to cooperate with the Trigger's context transaction (a local SubordinateTransaction with IsolationLevel="ReadCommitted").
For brevity's sake I've boiled down my scenario to a bare minimum: A SQL table [Test] with three columns (int Manual, int Automatic, IDENTITY int ID) needs any external updates on its [Manual] column to be applied to its [Automatic] column (with an additional sign change) through a Trigger.
A fairly direct translation of my non-Linq CLR Trigger to Linq yields the following code (the [Trigger_TestLinQs] SQL table has been modified to point to the Trigger's "INSERTED" table, [TestLinQs] points to the actual SQL table):
Code Snippet[SqlTrigger(Name = "LinQTrigger", Target = "dbo.TestLinQ", Event = "FOR INSERT, UPDATE")]
public static void LinQTrigger()
{
SqlTriggerContext triggerContext = SqlContext.TriggerContext;
if (triggerContext.TriggerAction == TriggerAction.Insert || triggerContext.TriggerAction == TriggerAction.Update) {
//using (TransactionScope scope = new TransactionScope(Transaction.Current)) { /* err 6549 */ using (SqlConnection connection = new SqlConnection("context connection=true")) {
connection.Open();
using (MyDataContext context = new MyDataContext(connection)) {
List<int[]> updates = new List<int[]>();
foreach (Trigger_TestLinQ test in (from t in context.Trigger_TestLinQs select t)) { /* err 6522 */
if (test.Manual != null && triggerContext.IsUpdatedColumn(0))
updates.Add(new int[] { test.ID, -test.Manual.Value });
}
foreach (int[] update in updates) {
dbo.TestLinQ test = (from t in context.TestLinQs where t.ID == update[0] select t).Single<dbo.TestLinQ>();
test.Automatic = update[1];
}
context.SubmitChanges();
}
}
// scope.Complete(); //}
}
}
Running this on SQL Server 2005 / .NET 3.5 beta2 produces an Error 6522 "Cannot enlist in the transaction because a local transaction is in progress on the connection." in the line executing the Linq query because the Linq DataContext apparently insists on opening a transaction.
The recommended pattern for DataContext query operations - running them inside a TransactionScope as indicated by the commented-out sections - unfortunately leads to a different Error 6549 in the TransactionScope constructor complaining about a missing MSDTC. And there shouldn't be a need for a distributed transaction here, should there?
Using different TransactionScope constructors (TransactionScopeOptions.Required, TransactionOptions(){IsolationLevel=ReadCommitted}) did not make any difference, either.
What am I doing wrong here? Is there any way for the Linq DataContext to attach to the CLR Trigger's ambient transaction?
Application Hangs With LINQ To SQL/SQL CE
Apr 17, 2008We have an application that is built with WPF/.net 3.5 and leverages LINQ to SQL. Everything runs as expected when our application connects to MS SQL Server 2005. We have made a SQL CE version of our database using the Microsoft SYNC framework, and SQLMetal.exe to generate our .dbml.
The issue we are running into is that our application hangs while our LINQ to SQL objects are delay loading an EntitySet at random places throughout our code. After futher looking into the issue, and testing our published application on various workstations, we have discovered that the application does work on one computer that has SQL CE version 3.05.5365.0000. It does not however work on any computers that have SQL CE version 3.05.5386.0000.
We are logging the SQL queries that the LINQ to SQL is generating and when we execute them in the the Visual Studio 2008 Query Analyzer, they run successfully.
Any ideas are appreciated as we have hit a dead end.
Thanks!
LinQ Enabled Website Problem.
Sep 1, 2007I am getting a reference problem in APP_Code when I am creaing LinQ enabled website. When I am creating LinQ enabled website at that time it adds some dll like System.Query, System.Data.DLinq, System.Xml.XLinq and in web.config file it adds
<system.codedom> <compilers> <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharp3CodeProvider, CSharp3CodeDomProvider"/> </compilers> </system.codedom>
automatically. Now the problem is when I add references like System.Query it does not show the Query namespace (It does not show any of the external dll added in the bin folder). And if we comment the
<system.codedom> <compilers> <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharp3CodeProvider, CSharp3CodeDomProvider"/> </compilers> </system.codedom>
in web.config file it works properly that means it shows System.Query and other refrences.
Please if there is any solution do reply,
Thank You..
Can't Get Linq To Recognize That Sproc Has Changed
Dec 21, 2007I have a GridView that is populated by a stored procedure via linq. I changed the stored procedure to return an additional column, but I can't get the additional column to show up in the GridView. The GridView has autogeneratecolumns=true, so if I were using a SqlDataSource the new column would show up automagically. But now it is not showing up and I cannot reference it. I can't figure out how to make linq recognize that my stored procedure has changed. I have tried deleting the sproc definition from the dbml file, making sure the partial class is removed the .vb file, refreshing the stored procedures list in database explorer, and adding the sproc definition back again (a hassle), but still it insists on defining only the original columns and not the new column. How do get linq to get back in sync with the database?
View 1 Replies View RelatedWebsite Using LINQ To SQL Development V Live
Feb 8, 2008Hello,
I have my local development evrioment and my live webserver in colo. The two different machinces both have SQL2005 and copies of roughly the same database. I use the one for developement and the other obviously for production. Currently I read in different connection strings from my web.config file for my live version v my development version so I can have different database names and connection strings.
I'm looking at moving to LINQ, but I can't figure out how I'd achive an equivelent flexibility as database names and connection strings seem to be hardcoded in to the class using it's designer. Obviously if modifing this wasn't possible, nobody would be using LINQ, so how do I work around this?
Thanks,
Joel Barsotti
Returning The Results Of A Linq Query
Feb 29, 2008I need some help. I have a function that used to use ADO.NET to return a dataview. Now I'm using linq, and I don't know how to make this work anymore.my original function looked like this: public DataView getIssue() { //do some ADO, return the dataview return ds.Tables["Articles"].DefaultView; } With this I could write Gridview1.dataSource = getIssue();I want to do the same thing with Linq, but I'm running into some trouble:Here's my function now:public DataView getIssue() { var query = from a in db.Articles join i in db.Issues on a.IssueID equals i.IssueID select a; DataView dv = new DataView(); dv = query.asdatatable(); return query; }OK, first off I can't use asdatatable since I am using a join, so I can't make the results of my query a dataview. I can't return the results of my query in this function, something that seemed simple to do in Linq now seems like something that may only be possible in ADO.Thanks for your time
View 5 Replies View RelatedLINQ And StoredProcedure Output Parameter
Mar 25, 2008Hi to all , I wrote a stiored procedure like below SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOALTER PROCEDURE SELET_AND_RETURN ( @opId Nvarchar(50) output)ASBEGIN SET NOCOUNT ON; SELECT @opId = NAME FROM TABLE1 PRINT @opId RETURN @opId;ENDGONow i include this procedure into my project, my problem is i dont know how to pass the output parameter from front end coding,
View 2 Replies View RelatedLinq To SQL Varbinary For Large Files
Jun 11, 2008Hello,
I have decided to use Linq for my current ASP.NET project and so far it has been good, but now I am implementing a system that will allow users to upload binary content such as pictures and videos. For ease of management and security, I have decided to store this content directly in the database. The performance hit is a minor concern because very few user-uploaded images/videos will be seen on any given page (usually just one).
From the limited tutorials I have seen on the internet, Linq supports the SQL Server varbinary column through its System.Linq.Binary class. This class does not appear to support STREAMS and instead opts to load all of the contents into memory. This content can then be converted to an array of bytes, which can then be output to the browser via the response stream. This is not good. What if I am sending a video that is very large? Varbinary supports up to 2 GB. I can't have a 2 GB video sitting in memory. It makes a lot more sense to stream it via a small buffer.
Obviously, I am going to limit the size of the content that users can upload, but the core problem remains. If I limit content size to 2 MB and I have 2 GB of memory on the server, then I can only serve 1000 users concurrently. In reality, that number would be much less because of other processes running on the server.
Is there no way to stream data from a varbinary column with Linq using a small buffer of bytes?
Do I need to implement some custom logic on my Linq classes? Since these classes are automatically generated, how would I do such a thing?
Thanks.
Using LINQ And Context Acts Like It Is In Transaction.
Apr 18, 2008I am using VS2008 Team Edition under Vista with SQL Compact 3.5
I am trying to develop an app using C# and LINQ and take advantage of the Sync services. The problem is that everything seems to work but nothing ever really gets saved out to the local .sdf file. I have all the SQL commands logged to the the console and they seem fine. I have SubmitChanges() wrapped in a try/catch and no exceptions are thrown. When I requery the context for the data the new added rows do show up. If while the application is open, I go to VS2008 and query the file I just added to, I don't see the new rows. If I exit the application and try I still don't see them. If I restart the application the rows show up. If I exit the app and refresh the connection to the .sdf file in VS and then restart the application the inserted records are gone.
They act exactly as if when I made my connection to the database I started a transaction (which I didn't do, at least no explicitly) that I never commit. Did I miss some basic point about opening a connection to SQL compact?
I connect when the app launches and I store the context in a member variable of my class which doesn't go out of scope until the application quits. I tried creating a new connection in a local method right around the call to SubmitChanges() but it behaved the same.
Below is the console output from adding the record and then updating it (two calls to SubmitChanges() )
INSERT INTO [Milestone]([Milestone_Key], [MilestoneType_Key], [Inspection_Key], [MilestoneDate], [Description], [RowVersion], [ModifiedOn], [ModifiedBy_Key], [CreationDate])
VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8)
-- @p0: Input Guid (Size = 0; Prec = 0; Scale = 0) [74ec904a-0c8d-46e5-8bea-af066d2c2f79]
-- @p1: Input Int32 (Size = 0; Prec = 0; Scale = 0) [3]
-- @p2: Input Guid (Size = 0; Prec = 0; Scale = 0) [57702e12-e0d8-487e-bf80-8066bf9ebdd5]
-- @p3: Input DateTime (Size = 0; Prec = 0; Scale = 0) [4/17/2008 6:50:52 PM]
-- @p4: Input String (Size = 0; Prec = 0; Scale = 0) []
-- @p5: Input Binary (Size = 8; Prec = 0; Scale = 0) []
-- @p6: Input DateTime (Size = 0; Prec = 0; Scale = 0) [4/17/2008 6:50:52 PM]
-- @p7: Input Int32 (Size = 0; Prec = 0; Scale = 0) [0]
-- @p8: Input Int64 (Size = 0; Prec = 0; Scale = 0) [0]
-- Context: SqlProvider(SqlCE) Model: AttributedMetaModel Build: 3.5.21022.8
SELECT [t0].[Milestone_Key], [t0].[MilestoneType_Key], [t0].[Inspection_Key], [t0].[MilestoneDate], [t0].[Description], [t0].[RowVersion], [t0].[ModifiedOn], [t0].[ModifiedBy_Key], [t0].[CreationDate]
FROM [Milestone] AS [t0]
WHERE [t0].[Inspection_Key] = @p0
ORDER BY [t0].[MilestoneDate]
-- @p0: Input Guid (Size = 0; Prec = 0; Scale = 0) [57702e12-e0d8-487e-bf80-8066bf9ebdd5]
-- Context: SqlProvider(SqlCE) Model: AttributedMetaModel Build: 3.5.21022.8
The thread 0x2604 has exited with code 0 (0x0).
UPDATE [Milestone]
SET [Description] = @p7
WHERE ([Milestone_Key] = @p0) AND ([MilestoneType_Key] = @p1) AND ([Inspection_Key] = @p2) AND ([MilestoneDate] = @p3) AND ([RowVersion] IS NULL) AND ([ModifiedOn] = @p4) AND ([ModifiedBy_Key] = @p5) AND ([CreationDate] = @p6)
-- @p0: Input Guid (Size = 0; Prec = 0; Scale = 0) [74ec904a-0c8d-46e5-8bea-af066d2c2f79]
-- @p1: Input Int32 (Size = 0; Prec = 0; Scale = 0) [3]
-- @p2: Input Guid (Size = 0; Prec = 0; Scale = 0) [57702e12-e0d8-487e-bf80-8066bf9ebdd5]
-- @p3: Input DateTime (Size = 0; Prec = 0; Scale = 0) [4/17/2008 6:50:52 PM]
-- @p4: Input DateTime (Size = 0; Prec = 0; Scale = 0) [4/17/2008 6:50:52 PM]
-- @p5: Input Int32 (Size = 0; Prec = 0; Scale = 0) [0]
-- @p6: Input Int64 (Size = 0; Prec = 0; Scale = 0) [0]
-- @p7: Input String (Size = 0; Prec = 0; Scale = 0) [added a record then changed a field and re-saved.]
-- Context: SqlProvider(SqlCE) Model: AttributedMetaModel Build: 3.5.21022.8
LINQ Layer - How To Invoke A Sort Function
Jun 5, 2007
Dear all,
I'm trying to create a BLL for an objectdatasource to used for a sorted DataGrid. I am trying to learn about how to use LINQ and I'm sure this is a simple question.
var query = (from p in db.MP3Collections select p).OrderBy(?????????);
Now I want to invoke the following method List<MP3Collection> GetAllMP3s(string sortColumns), which can contain a string name for the field in MP3Collection that is to be sorted (and optionally the "desc" tag).
Now I'm resorting tocoding the query on a case by case basis, which is very tiresome (see the partial code below). This works fine, but is very long and tedious coding. I'm not sure how to go about neatening the code, though am sure it involves the ?????? space above.
Any ideas?
public static List<MP3Collection> GetAllMP3s(string sortColumns)
{System.Diagnostics.Debug.WriteLine("Pure sort expression: " + sortColumns);
bool descending = false;if (sortColumns.ToLowerInvariant().EndsWith(" desc"))
{
sortColumns = sortColumns.Substring(0, sortColumns.Length - 5);descending = true;
}string[] columnNames = sortColumns.Split(',');
MP3DataClassesDataContext db = new MP3DataClassesDataContext();
List<MP3Collection> query = (from p in db.MP3Collections select p).OrderByDescending(p => p.fileName).ToList<MP3Collection>();foreach (string columnName in columnNames)
{switch (columnName.Trim().ToLowerInvariant())
{case "filename":if (descending)
{
query = (from p in db.MP3Collections select p).OrderByDescending(p => p.fileName).ToList<MP3Collection>();System.Diagnostics.Debug.WriteLine("Sorting filename descending");
}
else
{query = (from p in db.MP3Collections select p).OrderBy(p => p.fileName).ToList<MP3Collection>();System.Diagnostics.Debug.WriteLine("Sorting filename ascending");
}
break;case "filepath":if (descending)
{
query = (from p in db.MP3Collections select p).OrderByDescending(p => p.filePath).ToList<MP3Collection>();System.Diagnostics.Debug.WriteLine("Sorting filepath descending");
}
else
{query = (from p in db.MP3Collections select p).OrderBy(p => p.filePath).ToList<MP3Collection>();System.Diagnostics.Debug.WriteLine("Sorting filepath ascending");
}
break;
//OTHER CASES HEREdefault:
query = (from p in db.MP3Collections select p).OrderBy(p => p.filePath).ToList<MP3Collection>();
//throw new ArgumentException("SortColumns contains an invalid column name.");break;
}
}
//var query = (from p in db.MP3Collections select p).OrderBy(p=>p.fileName).ToList<MP3Collection>();return query;
}
How To Know The Record I Want To Query Doesn't Exist Via LINQ?
Aug 13, 2007Hi all:
for example: testDataContext db=new testDataContext();var res=db.tables.single(p=>p.columnName=="hi");
if there is a record in the database, it works well, but if there isn't , it will throw an exception, then , How could I know the record exists or not ? I don't think exception is a resonable way. and in my opinion, there should be--------even must be ------a resonable way , to evaluate the query result to a bool variable, then program could judge the bool variable like :
if(bExist) show("yes, I find it");else show("sorry, the record doesn't exist in the database");
I can't imagine I got the bool variable via exception...
thanks to all..