C# - Convert SQL To LinqToSql?
Feb 23, 2012
I'm going to use an existing query on an SQLCE database on Windows Phone. From what I understand, the only way to access a local db is via Linq2Sql.So, your challenge, if you choose to accept it, is to convert this fairly complicated query to Linq. I have doubts whether the linq driver is smart enough to use the exists functions.The inserts are for context only, to give you an idea of the db structure
DECLARE @OrderProducts TABLE(OrderID INT, ProductID INT);
DECLARE @Products TABLE(ProductID INT, ProductName VARCHAR(32));
INSERT @Products VALUES
[code]....
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Oct 28, 2011
I wonder if somebody could point me in the right direction. I've recently started playing with LinqToSQL and love the strongly typed data objects etc.I'm just struggling to understand the impact on database performance etc. For example, say I was developing a simple user profile page. The page shows basic information about the user, some information on their recent activity, and a list of unread notifications.
If I was developing a stored procedure for this page, I could create a single SP which returns multiple datatables covering all of the required information - resulting in a single db call.
However, using LinqToSQL, this could results in many calls - one for user info, atleast one for activity, atleast one for notifications, if I then want further info on notifications this may result in further calls - multiple db calls.
Should I be worried about the number of db calls happenning as a result of using this design pattern? Ie, are the multiple db handshakes etc going to degrade my db etc?
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Sep 14, 2010
I'm using LinqToSql to talk to my database. It's working great but I would like to know if there are pending changes. I know how to endedit() and submitchanges() on the underlying context. But is there a property that will tell me if changes have been made? I've looked through the properties and methods of both the bindingsource object and the datacontext but nothing is popping out at me.
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Nov 2, 2009
I have a DataGridView.datasource bound to LinkToSql. I fill the data based on a sequence number. If the sequence number is not part of the the data, I will need to add a record. This should be easy and make sence, but it would appear, at least to me to be a bit more difficult.The grid will not add a new record if the LinqToSql query is empty
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Jan 21, 2010
lately I've been experiencing LinqToSql + Sql Server Express 2005, and it was a great journey (muddy) anyway .... I'm at the point that I want to make a Backup/Restore for the database backup for SSE is as easy as a simple copy paste of the mdf file, but the problem that I can't copy the file while the server is using it, server doesn't let the file go untill the app is closed or after about 4 - 6 minutes of idle time,
[Code]...
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Aug 19, 2010
I have a linqtosql dbml where I dropped a stored procedure into the designer interface.
Stored procedure name:
GetUser(@userid int)
Select * from users_tbl where userid=@userid
[code].....
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Feb 15, 2011
I'm using LinqToSql classes in an ASP.NET website and let's say I have an entity named Testimonials. Two pages utilize this type - the first being a list of all existing Testimonial records and the second being an add / editor with which to manage the records. [Code] This allows population a DataGrid with the returned items, however on the add / editor page we alter the query ever so slightly: [Code] This query dies, prior to even trying to populate anything, with the following message: [Code]
I have pretty much identical methods for other data objects which have been and still are executing just fine. One immediate difference I can think of is that this table has been recently updated in the database, removed from the dbml designer and re-added to the dbml designer. None of the other tables have undergone this process for some time. [Code] Why is this exception occurring and how can I configure my project appropriately to correct the issue?
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Sep 8, 2009
I have a smalldatetime column in SQL that can have a null value, but when I try to insert a null value using SqlTypes.SqlDateTime.Null and LINQtoSQL it puts in 1/1/1900 instead of NULL.
What is the best method to insert a null, or am I doing it at the moment. If I am using the correct method at the moment, what should be done to prevent the 1/1/1900 being displayed on my fields in a WPF application.
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Sep 16, 2009
Dim query = (From p in Parent _
select _
p.ID, _
Tags = String.Join("|", p.Child.Select(Function(c) c.Tag.TagName).ToArray)).Take(100)
In the above query, when using Take to limit the rows returned, a separate SQL query is executed for each row to return the 'Tags' field. If I remove Take(100), a single query to sent to Sql Server.So, how do I limit the number of rows returned, while preventing a new sub query being executed for each row?
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Aug 23, 2011
On a client i have an anonymous list containing a multi-column primary key previously selected from the DB.Then i need to select all the records from the DB that equals the primary key list i have stored in the memory.[code]
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Feb 22, 2010
See where my vb.net equivalent of a working c# assignment statement is not working?
bytes(i / 2) = Convert.ToByte(hex.Substring(i, 1), 16)
Here's the c# followed by the vb.net function.
private byte[] StringToByteArray(String hex)
{
int NumberChars = hex.Length;
byte[] bytes = new byte[NumberChars / 2];
[CODE]...
And the vb.net that is throwing the error within the for loop
Private Function StringToByteArray(ByVal hex As String) As Byte()
Dim NumberChars As Int16 = CShort(hex.Length)
[CODE]...
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Dec 8, 2009
my project was intially mandated to be done in c#.however a large contributor to the project wrote much of the business logic, which he knows well, in vb.net.How difficult would it be to convert the following c# code into vb.net.
[Code]...
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Oct 30, 2010
i wanna try to convert this ASM code into vb.net or at least find a solution that will allow me to enable this script after creating a handle on a kernel32 process.
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Apr 7, 2012
I am looking for some library or code that will allow me to convert mp4 video to mp3I want it to be for free and compatible with the latest .NET framework (4).Also, if possible, I am looking for a free ffmpeg wrapper than I can have in my vb.net application without trial or messageboxes.
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Aug 11, 2010
Will Microsoft Visual Studio 2008 convert my app to an app I can use on the Internet. I've used it to help convert up from 2005 but I'm looking so save time in creating a web app version.
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Aug 11, 2009
I developed a windows application in VS2008 as 2.0 . I would like to migrate to 3.5 . This really basic but how do I do that? It seems like I should just change a few parms somewhere, but I can't find it.
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Jul 2, 2007
I have my running application in vb 6.0, & needs to convert in C# .Net platform
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Jan 8, 2010
How do I convert a hex to an int. I know:
Dim hex as String = "FFFF"
Dim int as Integer = Val("&h" & hex)
The problem is that it only returns a signed integer, so the example above gives -1 instead of 65535. Is there a way to make Val return a Long instead f.ex. , or an other way ?
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Mar 27, 2009
as the title sayshow can i convert a bmp file to jpg file "real conversion not only changing the file file extension"or to a gif file
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Aug 3, 2011
typedef
struct {
unsigned
long
[code]....
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Jul 20, 2011
I was wondering if someone could convert the following to VB.NET.
[code]...
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Oct 7, 2009
I have some C# source code that I got off the Internet and I want it in VB.NET. How would you convert it because I don't know C#.
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Sep 10, 2009
I got this class parameters in C# and I can't convert one parameter to VB. [:(]
public static string PageLinks(this HtmlHelper html, int currentPage,
int totalPages, Func<int, string> pageUrl)
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May 6, 2010
Is there any tools that I can use to convert c++ code into vb.net code?
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Apr 12, 2009
How can i convert doc in vb(windows application form) pdf format+free pdf generator can i download n can be used in vb.net.
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Dec 12, 2010
convert below code from C# to VB
protected void Page_Load(object sender, EventArgs e)
{
Validator1.Enabled = Request[DDL1.UniqueID] == "2" ? false : true;
}
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Apr 14, 2011
I'm currently converting a VB6 app to vb.net 2010 and i'm struggling to convert the following code and was hoping that someone could assist me. Im rather new to .Net [code]...
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May 13, 2009
How to convert to jpg file to Pdf file using vb.net
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Sep 28, 2010
I have the below code that searches through directories and displays the largest file in the directory. the problem is that it displays it in KB - how on earth do I convert it to MB? The file size comes out way too large so want easier reading
Private Sub btnGetMax_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGetMax.Click
ClearList()
[Code]....
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May 18, 2009
How can I convert mdf to mdb thru vb.net code? I know it can be done using Access Import but I don't want my client to open Access just to convert a database from mdf to mdb. It will be more convenient for my client to just click a button in my vb.net apps to convert mdf to mdb.
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