I need some help with correctly implementing the USING statement with strongly typed TableAdapters..[code]How can I use the USING keyword instead of Try.. Finally for the connection object?
View 2 RepliesI have read and worked through all of the examples in the book "ADO.NET 2.O", but there is so much there with so many ways to handle data, I am having difficulty translating the examples into my own real life application. I am confused about creating runtime connection strings, connection strings in my app.config file, connection strings in the properties for a sql connection control, etc.
I have a midichildform with a datagridview control, and I use a table adapter to edit and update the SQL Server 2005 Express edition database. There is no problem there. However, I also have a button control that I want to use to "process" the data that has been updated with the table adapter. I want to open the updated table, read each record on at a time, manipulate the data and add a records to another table. Do I have to create a connection string and an oleDBconnection? Or can I somehow use the connection string that is in my app.config file? [Code]
When a person makes changes on my datagridview and closes it, I want it to automatically go into the database and update in a new column (which is already been created) the text "changed".
Everything in my tableadapters already works. Its just the VB part which I dont know how to call the update command. Here is what I have in my updatedataset().
Private Sub UpdateDataSet()
Dim datasetChanges As datasetTs = New datasetTs
Me.bindingsourcet1.EndEdit()
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Most of my programs use table adapters, and the connection strings are stored in app settings. This works fine, but was a real PITA when switching from development to production environment. I had to change manually the connection strings before and after starting my work on any app.
After a bit of research I found how to switch connection strings for table adapters dynamically. By simply adding a custom property for connectionString, I was able to acheive this. But I still have to add code in the new event for each application so the connection strings get switched when it loads. (My connection strings are kept as an app property setting in a common DLL. I just keep one copy of the DLL with my connection strings locally, and one copy o the DLL with the production connection strings on the production server.)
I'd like to take this one step further and have either have the datasets change the connection strings for all table adapters they each contain when they load using the new event, or do the same from a VB module. I may have up to 3 datasets at any one time.
I added few new tables on data sheet (file name nwinddata.xsd) but the new added table adapters does not appear in toolbox whereas the old adapters were appearing. I read somewhere and followed their advice to delete the project and re add the project to the solution explorer, did that, now i can't even see old adapters in tool box all gone.When i restored my backup old adapters appear in toolblx but few days of will be lost which i don't want.
View 2 RepliesI need to change the connection string of all tableadapters at runtime, can anyone tell me for the best way to do it?I have a conection string in my settings, that i can't change at runtime (application scope), i could go to dataset.designer and change the value to a new variable but i don't think this is a good method.
View 3 RepliesCause I just dont get whats going on here. I have a bunch of combo boxes linked to their own Tables in my database, 14 in total. My problem is that only 13 of them work and every one I add after 13 doesnt work for some reason.So I make a ComboBox, press the arrow in the upper right corner and click "Use Data Bound Items", Then I fill in the rest as it should be. But only the "Selected Value" function actually works. I can fill in data to my other tables manually through this ComboBox, but I can not view my Data Source! If I use the same ComboBox and use any other Table it works, but not anything past my 13th table. The BindingSource is there, so is the TableAdapter. If I preview a select quary to the database it works as it should. But for not in the ComboBox!
Its driving me mad, can someone explain to me what might be going on here?
i have a problem. I have database with a tableadpater. i want to get the userid with this tableadapter.
Dim dsGN As New ForumTableAdapters.Message2TableAdapter
Dim dtBetrieb As Data.DataTable = dsGN.GetUserIdFromThisMessage(ConversationID)
For Each objRow As dsGN.Message2Row In dtBetrieb.Rows
mystring = objRow.UserId.ToString
Next
i get the error "dsGN.Message2Row is not defined" The Name ob my table in the database is "Message"
I'd like to keep all my SQL data related code in a separate class and only have UI related code in my main form. However, the TableAdapters are automatically placed on the main form and, of course, the auto-generated code placed in the Form_Load event.
Obviously, it's easier to keep it like that but is it possible to move them to a different class?
I am retrieving data from my database using a TableAdapter. I was wondering if there is some way I can tell (or be informed) that the data has changed and I therefore need to do another Fill? That way I can just Fill on demand rather than every time the user requests to see the information and I am forced to do a Fill before showing the data because I don't know if is current or not. For the record I am using an ODBC connection string to access a Pervasive PSQL database
EDIT I was thinking I could check the last write time of the MKD file to check if this has changed but this doesn't seem to be reliable as it is not written to until the connection is closed. Does anyone know the circumstances when this is written?
For some reason I'm unable to set the commandtext of the tableadapter. I have the following code:
'Prepare the sqlcommand
Dim dd As System.Data.SqlClient.SqlCommand
dd = new System.Data.SqlClient.SqlCommand
dd.CommandText = SqlUsers
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I was Created TableAdapter through Configuration Wizard , and i applied joins and Filters on the wizard. Finally i am getting the rows which i want, and now one table was created in my dataset.
If i update few records in my database, is there update also in this table?? why b`se this table is not in the Database right?
I am using an Access database (mdb file) and for the first time ever I'm connecting to it using a bunch of TableAdapters created in a DataSet.xsd file.I added an Insert query to a TableAdapter, and now I need to retrieve the ID (autonumber) of the last inserted record. Usually, I would send a "SELECT SCOPE_IDENTITY()" query and it would return the ID, but for some reason I cannot get this to work with the TableAdapter.
I tried two methods:1. Add the SELECT SCOPE_IDENTITY() query directly after the INSERT query in the TableAdapter. This method is described in every website I found by googling my problem. Suppose my INSERT query is this:
INSERT INTO Test VALUES("1", "2", "3")
then I should now modify it into
INSERT INTO Test VALUES("1", "2", "3");
SELECT SCOPE_IDENTITY()
I also changed the ExecuteMode to Scalar.
Ok, I run this code, but it doesn't work. It gives me an error saying Characters found after end of SQL statement.Is it because I am using Access and not SQL Server maybe? I dunno... But whatever I try it doesn't work. It's not a spelling error, and I did type the semicolon to separate the two queries so as far as I know it should work.2. Add a separate Select query (selected 'Select query that returns a single value' in the designer) that simply executes this:
SELECT SCOPE_IDENTITY()Then after using the Insert query I can simply call this query method and get the last Id. But unfortunately this doesn't work either. It doesn't even let me add this query in the designer, it says Unable to parse query text.
Running off my laptop: Visual Basic 2010 Express & SQL Server 2008 . I've successfully been able to use the connection wizard to connect to my database in vb.net and read/write data using datasets/tableadapters/binding_source etc.
Now I am trying to create an SQL connection via code to connect to my database to do some more complicated queries. I was successful in being able to connect to my database with SQL, but by doing so it produces an error when it tries to run any .Fill() methods from my TableAdapters below. The error produced is the following: "SqlException was unhandled. Cannot open user default database. Login failed. Login failed for user 'Chris-PCChris'".
If I remove my SQL connection code, the TableAdapter.Fill() methods will work fine.
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In VB6 I load a recordset containg all of the records (6 fields per record)in a table into an XArray and then manipulate the records in the array and then write them back to the original table. The array issorted by the first field (1 to maybe 8000 or more) I need to find records in the array by an ID field and then move them (because of some external criteria that happens many times) from say number 400 to number 375. Then all of the other records between 375 and 399 were renumbered up 1 to fill the gaps left by the move.
The XArray worked well as it could find and also move to a next record easily to facilitate the revisions to each record quickly. Everything is done in VB6 in code and nothing visual needs to be shown to the user until say 2000 of these external changes are complete. What is the best, most efficient way to do this in the .Net framework in VB2010. Datasets, Dataviews. tableadapters, arrays. enums ?
See
Public Class Form1
Dim sql As String
Dim conn As New OleDb.OleDbConnection
Dim da As New OleDb.OleDbDataAdapter
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The problem, The INSERT statement works fine in the form load but not in the button click event?
I was convinced that If <expression> Then <statement [:statement]> Else [statements] in concrete form of If a = b Then SayHello() Else SayBye() End has sense. I read article on msdn on If-then-else, but I forgot why I was reading, so I concluded, that snippet above means this
If a = b Then HelloIsSaid : IsNotEnded Else ByeIsSaid : IsEnded But I have tested it now, and I see, that Else without statement is nothing more than decoration. It would be pretty good if it had function I described. Do you think its good request? Or do you know any circumstance where this Else has some function?
y friend and I are re-learning Visual Basic, and we are stumped on this bit of code.
For intAsterisks As Integer = 0 To intLine - 1
lblAsterisks.Text = lblAsterisks.Text + "*"
Next
I have the following SQL:
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I want to put it (the select count statement) in this LINQ statement so I can get the sales count in my linq statement: Dim TheLeads = (From L In DB.Leads Where L.IsDeleted = False Select L).ToList() Is this possible to do in LINQ?
How do I assign a My.Settings.Item connection string to cmd.Connection connection string value?
Dim cmd As New SqlCommand()
cmd.Connection = My.Settings.Item("csStaffHoursWorked")
cmd.CommandType = CommandType.StoredProcedure
cmd.CommandText = "spSaveDeltekImport"
add an if statement and an exit statement to my do loop that exits when my future value (FV) is greater than 1000, then to change the exit statement to a continue statement so my loop will continue even though my fv is greater then 1000, point is to get this to run even though my if statement doesnt do anything. problem something wrong in my code and an exception error (xception of type 'System.OverflowException' occurred in mscorlib.dll)
so can someone show me where or why I have an error is, what am I overthinking now! I could use a hint, OMG i could use a tutor for that matter
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A co-worker wants to convert the following IfThenElseIf statement into a Select Case statement.
Explain why this is not possible.
If temperature = 100 Then
X = 0
ElseIf population > 1000 Then
X = 1
ElseIf rate < .1 Then
X = -1
End If
I cant get this SQL statement to insert any of the values in the form to add to the database
sql
sql = "INSERT INTO prevresults (ExamDate, ExamTime, CorrectAnswers, PassPercentage) VALUES (date.now, time.now, rightanswers, percentage.text)"
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Is there a way to display the connection properties dialog for connection string browsing(for database) in run time?
As I want the user to be able to connect to various database using the GUI.
i have an application. which is executed after every 5 mins. i have an open connection but it gives me the following error:
ExecuteScalar requires an open and available Connection. The connection's current state is closed.
my code is something like this. I have shown where all i am using ExceuteScalar()
Sub Main()
Try
connection.open()
cmd.ExecuteScalar()
[code]....
After running the following sub (VS debugger), I try to detach the database in SSMS, but it shows the connection open still and won't let me detach. If I close program in debugger, the database shows no connections. I check the dataadapter's connection in the finally block and is shows closed. What gives
Private Function ClientMasterDBFiles(ByVal MasterClientDBConnection As String, ByVal DBName As String) As DataTable
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I have a simple scraper. It works on some websites, but on some there is this Error:
Quote:
IOException was unhandled Unable to read data from the transport connection: The connection was closed
It is occuring at "Dim htmlresults As String = Urlcontents.ReadToEnd()".
'Create the HttpWebRequest object
Dim req As HttpWebRequest = WebRequest.Create(URL)
'Set the timeout to 1 second (or 1,000 milliseconds)
req.Timeout = 10000
[code]....
I am attempting to write a program that will disable the Local Area Connection while leaving the Wireless connection enabled. My company is using net-books in our stores to demo air-cards and we need to keep them off of the LAN. I'm new to VB and VB.net, and it's been a while since I did any type of programming. I've gathered some code that others have posted in forums and tutorials and I'm working through a tutorial book, but I finally believe that I am stuck.
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i make a class and when i call on form then that error occurs "ExecuteNonQuery requires an open and available connection, the connection Current stat is close "
Class Code isImports System.Data.SqlClientImports System.DataImports System.StringPublic Class DatabaseKits Dim Cn As New SqlClient.SqlConnection Public Function BuildConnection() As Boolean Try Cn.ConnectionString = "Persist Security Info=False;Integrated Security=True;Trusted_Connection=Yes;database=BizAimsPro2008;server=Server-2k3s" BuildConnection =
[code]....
I am connecting to a data stream that pushes data continuously and when I tried to set up a network stream I just could not connect and kept getting the 'not found' error. I used the httpwebrequest with webrequest.keepalive = true and started to consume the data by reading into a buffer and then appending to a stringbuilder. Once the stringbuilder reaches max size I flush it to a text file. The problem is that I get disconnected from the data stream because I am not reading the data fast enough. I need to keep the connection open and read the data while ensuring data gets stored in text files. If I use method "CONNECT" it does not connect to the stream.
While (True)
webrequest = DirectCast(Net.WebRequest.Create(url), HttpWebRequest)
webrequest.Credentials = New System.Net.NetworkCredential(username, password)
webrequest.Method = "GET"
[code]....
should I increase the buffer size and if so what is the max? that would mean I can read more data at a time and keep up with incoming push. Disparate here.
ACtually also I noticed that it gets stuck on this line
numbytesread = responseStream.Read(bufferread, 0, BUFFER_SIZE)
and then eventually I get disconnected.