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.
View 3 RepliesWhile working on some functions that update my database, I was writing some quick tests just to make sure my functions were executing properly. When it comes time to actually update the database I can pass a transaction to a function and then commit it:
user.Assignment("assignment value for some column in table", connection, transaction)
transaction.Commit()
I am curious if there is a way to write a quick test that can verify that the transaction will actually update certain rows before committing?
(pseudoish-code)
user.Assignment("assignment value for some column in table", connection, transaction)
If Not transaction["SomeColumn"] = "Expected value for SomeColumn"
assert("ColumnName was not going to be updated to the expected value!")
transaction.Rollback()
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
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I'm making a form with a checkbox where if checked a target file is appended with text-A and if Unchecked the file is appended with text-B How can I do this?
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My code simply runs procedure at SQL Server and copy data into excel. Excel is then saved, closed and released from memory. After that I have added code for Cells alignemnt and Cells formatting and problem raised again and excel is again pending in running processes. 4 rows of sheet alignemnt causes that, and when I comment them, then its ok again. Same when I used formatting by .NumberFormat.
Public
Sub Main()
Dim xlApp
As Excel.Application, xlWB
[code]....
Is there any way to determine that a system has automatic updates enabled and has the little yellow security center icon indicating that updates are available? I'd like to drop a little service on one of my servers to monitor for that condition but can't find a good resource to get started.
View 12 RepliesI 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?
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
View 6 Replieslately 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,
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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].....
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?
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.
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?
Any ideas on how I handle the following error thrown in the SqlDataAdapter.Fill as a result of the BeginTrans in the callee?
System.InvalidOperationException = {"ExecuteReader requires the command to have a transaction when the connection assigned to the command is in a pending local transaction.The Transaction property of the command has not been initialized."}
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Public Sub ExecuteTransaction(ByVal connectionString As String) Using connection As New OleDbConnection(connectionString)
Dim command
As New OleDbCommand()
Dim transaction
As OleDbTransaction
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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]
View 1 RepliesI'm creating an application which has an scheduler to print and it checks if there is a pending job on the print queue before it prints the next file. I use a timer which checks if there is any file to be printed on my database. Example, the timer ticks and selected 10 files to be printed, it should print the 10 files 1 at a time, if there's no print queue, that's the only time the next file should print. I think another timer is required which will keeps on checking if print queue is done. How will i do this?
View 2 RepliesI think I'm making a mountain out of a mole hill. I have a DGV that contains 5 columns made up from 2 different DB Tables. Here is the procedure that populates the DGV.
Private Sub SetBindingSources(ByVal strClientID As String)
Try
'This section of code populates the grdAddresses DataGridView
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I have a BindingSource bound to a DataTable.
I use the BS Filter and would like to iterate the filtered dataset of the DataTable using the Bindingsource.
I know I can do a MoveFirst and the MoveNext and each time using the BS.Position get the correct row in the underlying DataTable. But how do I know when the sets ends? I'm sure there must be such a property, but what is it?
I'm trying to display a DataTable using a DataGridView and a BindingSource as such: (assuming the DataGridView1 and BindingSource1 has been added using the IDE)[code]...
View 3 RepliesI am using several tables, say A, B and C. How can I put these into a variable so that I can use e.g.tnameBindingSource to represent the bindingSource according to the parameter passed?I have spent hours trying to do this in vain.
View 1 RepliesI want to convert this vb6 code in vb.net using BindingSource
Do Until recordSet.EOF
if isnull(resordSet!FieldName)=true then
recordSet.delete
end if
recordset.movenext
loop
I have one datagridview control, a BindingNavigation and a Binding control on my form. I populate the datagridview control through the code. Moreover, the datasource properties of the DatagridView and the Binding controls are assigned a value through code (I didn't specify anyting in the properties window). The same for the bindingsource property of the BindingNavigation control (I assign a value trhough code). My code is the following:
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This code brings and shows the right results in the datagridview control, but the navigator control is inactive. I know that I have to bind the controls(DataGridView + BindingNavigator) to the BindingSource control. Is this a problem that I tried to do this by coding?
I have a bit strange problem in my application. I have more binding sources then one in my different forms. All of them work great when editing, deleting the data except one. But this one is a bit different from others. I'm using it only for updating and deleting. You can't add new records using it. And also its dataset doesn't contains any Insert commands in it. That's the difference.Now problem is:
After deleted the rows (using BindingSource.RemoveCurrent), it doesn't mark rows as deleted. I call BindingSource.Count method after deleted rows, it sill counts deleted rows. So it seems it doesn't update the dataset. But it is. Dataset.HasChanges returns true.
How may I filter a bindingsource between 2 numbers? Obviously "column_name BETWEEN Num1 AND Num2" does not work, since between is nor supported.
View 5 RepliesHow may I filter a bindingsource between 2 numbers? Obviously "column_name BETWEEN Num1 AND Num2" does not work, since "between" operator is not supported
View 4 RepliesI'm trying to use the bindingsource.find method to match a datarow column with a user entered text. I know that using BindingSource1.find("columnName", searchString) will work when the user enters the exact string. What I would like to know is how to find a row that is close to the string using a wildcard search... a good example I guess is:dim searchString as string = textbox1.text 'lets say the user enter "se"dim index as integer = myBindingSource.find("columnName", searchString) 'I would like to find the firs record that starts with "se"I can achieve the idea using the bindingsource.filter method but this will interfere with other parts of my application if the bindingsource is changed.
View 6 RepliesI want to sort the binding source column (Product Code) which formatted like (AA-AAA AAA AAAA)
but i do not want straight sort on product code column, i want the sort as :
substring of 1,2 + 8,3 + 3,3 and then the rest of the column.
I know i can do it in the table direct using the OrderBy and the substring function, but the problem is that sort is not static it is dynamic according to different status means it change the substring order.
I'm using a SQL Server database and a bindingsource, and i want to filter a numeric field in order to, for instance, when I write 1, the grid shows all the rows in which that field begins whith 1 (1,10,14...). In order to do this, I have to convert the field to varchar, but VB shows an error message when using cast or convert functions. I have this sentence in my
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I consider myself fairly new to VB.NET, so maybe you could help me here.I have a bindingSource which is bound to a dataset. I have a filter on the bindingsource. My problem is that when I add a new row, with BindingSource.AddNew, even if it does not match the filter criteria, it still isn't filtered out.Could it be that the bindingsource filter never filters out detached rows? If so, what can I do in this situation?
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