Dataview Generates Reset Event After Dataadapter.fill On Datatable?
Jan 9, 2011
VB2010, MySql I have a dataview generated from a datatable using a rowfilter.I have event handlers listening to the dataview.listchanged event. To keep the datatable (in memory) in sync with the mysql database (on a remote server), i issue datadapter.fill commands every now and then, the objective being that only the changed rows in the datatable (as a result of the fill) would generate a listchanged event on the dataview.To my surprise the dataview_listchanged event fires after refresh by the dataadapter.fill method, however the ListChangedType it gives is: ListChangedType = reset. I would have expected a ListChangedType.ItemChanged for every changed datarow.Since the dataview is used to populate a large storage yard, i am now forced to repopulate the whole storage yard, which is a time consuming business.Is there a way to only generate DataView.ListChanged events for rows in the datatable that are actually changed by the datadapter.fill method?
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Mar 12, 2011
At the top of my code for the form I have the following statements (and some other unrelated ones to):
Dim LastDataRow As DataRow
Public Event RowChanged As DataRowChangeEventHandler
When my form loads I run the following line of code:
AddHandler dt.RowChanged, New DataRowChangeEventHandler(AddressOf Row_Changed)
After the form loads I have a FetchData button which connects to the database and brings the records into a datatable object. During this fill operation my Row_Changed event fires (for every record I think) and tries to run DataAdapter.Update(DataTable) (pseudocode) which ultimately fails because I haven't yet created commands. The error I get in my Row_Changed procedure is:
Update requires a valid InsertCommand when passed DataRow collection with new rows.I hadn't even planned to use an InsertCommand at all since I will not be allowing users to insert records from this form. I do plan to allow them to delete or modify existing records, but not insert new ones.run my AddHandler statement after filling the datatable. However, I'm trying to figure out how to rewrite my code so that I can refresh the datatable without closing out the form/application and having to open it up again. I think that's a problem for a separate discussion.
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Nov 20, 2010
If want to do a DataView.Find on a DataTable that is already 'ORDERED' by the Column I am seaching, so a DataView.SORT should not be necessary, but it throws an Exception if I don't give a .sort command before the .find command. Is there any way to avoid this apparant duplication ? and speed up the search time. Its a very large table - 1 million rows. I am using VB 2010
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Mar 15, 2010
I have a datatable and I apply a filter to the defaultview.rowfilter property of that datatable. If I then loop through the rows collection of the datatable, will I only be able to see those rows that the filter applies to, or will it loop through all the rows?
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Jul 20, 2011
I am trying to add a parameter to a sqlDataAdapter. I have tried to use parameters.add() but the adapter is not a sqlCommand. Here is some of my code.
Private Sub convertToCSV(ByVal SqlQuery As String)
Dim Dt As New DataTable()
Dim SqlCon As New SqlConnection("Data Source=db;Initial Catalog=productionservicereminder;User Id=id;Password=pass;")
[Code]....
Basically I am trying to do something like this:
Ada.Parameters.Add(New SqlParameter("@pgid", pgid))
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May 7, 2009
There is no other workaround at this point, so here is what I am attempting to do:
1. Fill a DataAdapter from an Excel.xls spreadsheet.
2. TRUNCATE an existing SQLServer2005 db table that matches this excel spreadsheet.
3. UPDATE that SQL Table with the DataTable filled from the excel spreadsheet.
If there are anyother suggestions (OPENROWSET/DATASET is not possible for my situation, in or outside of a SProc),Here's the current dev point I am at --- no errors, but also the SQL table does not update.
[Code]...
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Oct 5, 2009
I have a problem with access database in my vb project. I would like to fill the listbox with objects from my database. I've attached two images. In first image when i'm using command objDataAdapter.Fill(mydataset....) i can select table property(zaposlen). But in second image or in my second app i dont have an option to select table property in my dataset(there is nothing to select). If i select DataTableDataTable i get next error: DataTableDataTable' is a type in 'WindowsApplication1.baza_podatkovDataSet' and cannot be used as an expression.
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Mar 29, 2009
When I use the dataAdapter.fill(ds,tableName), it reports an error: "Failed to enable constraints."Yes, I changed the selectcommand.I know if I modified the selectcommand, and if it will take diffrent columns result, this error will be reported.
[Code]...
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Jul 21, 2009
i try to use this yesterday it work fine..now, it will process too slow.. when fill the dataadapter into the dataset..here is the code it gives 20 menutes still no result.. "no error, no comment. it's like standby
Dim conn1 As MySqlConnection = New MySqlConnection("server=pc1;user id=user;Password=12345;persist security info=True;database=mytsmobile")
conn1.Open()
[code]....
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Nov 9, 2010
[code]Where I add my parameter, I am trying to have it pull records that contain the text that is in the jpDescTextBox instead of being exactly equal to it. I have tried using wildcards such as * and %.
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Apr 20, 2012
I there a way to set up my DataTable so a field (or all fields can allow nulls if you can't set just 1 field) so oIDbDataAdapter.Fill won't leave out DataRows where a field contains a null value?
Dim oSqlCommand As SqlClient.SqlCommand
Dim oIDbDataAdapter As System.Data.IDbDataAdapter
oSqlCommand = New System.Data.SqlClient.SqlCommand( _
[Code]....
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Jan 14, 2012
I wrote a code as:
Dim dTable
As
New DataTable
Dim dAdapter
As SqlClient.SqlDataAdapter
[Code]...
My Problem Is that when i Update Table thought dataadapter but Table didn't get auto-increment ID. When i reload the from then i get all data. how do synonymous dataAdapter and DataTable during when i call dataAdapter.Update methor.
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Jun 1, 2009
I start by looping through a string array, parsing out the strings I want and saving them to a temp table (I believe this part is working).Then, I take a DataView of the tale to get only the unique values from the rows.Then, things get messy, I need to get these unique values into my dataset. I been trying to do so using the DataView and also by passing the View to a new temp table then looping the values into the DataSet
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Jan 2, 2010
How to create a dataview from a datatable?
What is the basic use of the created dataview?
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Dec 8, 2009
I populate a datagridview using a bindingsource and dataadapter. So I join 3 tables in the view to get the data i need.
so I have my view as a child table in my dataset. and a table called classes which is the parent table. So when I select a Class(class 1A for example), my datagridview displays the pupils in that class.
Now i need to add another relationship in the dataset. so when I select a day in a monthcalendar, I need to add 5 checkbox columns for each day to my datagridview. Should I add these 5 columns to my datatable? i'm not sure what the best way is.
Then for each day I tick I have to save to my pupil_job_day table. I will save the peoleid,their accountid and the date. please help me
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Feb 15, 2012
I'm loading a DataGridView from a DataView which collects data from a DataTable. I use the DataView to filter, this is the
Dim dv As New DataView
dv = DataSet4.Tables("TABLA1").DefaultView
dv.RowFilter = "propietario='" + NombrePro + "'"
[code].....
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Aug 6, 2010
I am trying to add NewRow to the database by using datatable in dataset, but before I do that I want to make sure that row is not already there. I create new row for the datatable I am working with, fill it with information. I fill datatable with the row from database that has the same primary key as my NewRow by using tableadapter.fill method, but when I do that my NewRow that was never added to the datatable is filled with information from database(and not information that I assigned to it). I count rows in my datatable before I fill it and it's 0, so why is my NewRow affected by Fill command? (I am using VB.NET 2005 Framework 2.0)
[Code]....
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Aug 5, 2011
I want to find a particular ID in a DataTable, I am using a DataView to filter the results, but how do I know which row in the original table the filter view corresponds to? Any ideas? In know I could use LINQ but I don't think this would help either?
[Code]...
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May 5, 2010
I have application in .net 2.0 in which I have a DataTable object globally in my application and have different dataviews in whole application.
When an action performed i have create many threads lets say 5 in which data is read from different dataview, meanwhile while 2/3 threads are reading data(not all 2 more left to read data) a thread write data in datatable. So we get exceptions like "Enumeration update" or "parameter not null" type.
I have use ReadWriteLock for this but do not find any luck it gets stop on ReaderWriterLock.AcquireWriterLock().
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Feb 21, 2011
For my app users can enter a SELECT statement themselves. This can be any select statement at all, it will be mainly used for creating a quick view e.g. SELECT * from table1 LEFT OUTER JOIN table2 on table1.id = table2.id.
Whatever this select statement maybe I load it into a datatable (after checking for no nasty stuff of course) in vb.net. I want to know the table names so I can query the database again for validation purposes on things like datatypes etc.
da.SelectCommand = New SqlCommand(sqlStatement, tempDB.Connection)
da.MissingSchemaAction = MissingSchemaAction.AddWithKey
dt = New DataTable
da.Fill(dt)
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May 18, 2011
For my app users can enter a SELECT statement themselves. This can be any select statement at all, it will be mainly used for creating a quick view e.g. SELECT * from table1 LEFT OUTER JOIN table2 on table1.id = table2.id.Whatever this select statement maybe I load it into a datatable (after checking for no nasty stuff of course) in vb.net. I want to know the table names so I can query the database again for validation purposes on things like datatypes etc.
da.SelectCommand = New SqlCommand(sqlStatement, tempDB.Connection)
da.MissingSchemaAction = MissingSchemaAction.AddWithKey
dt = New DataTable
da.Fill(dt)
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Jun 25, 2010
im trying to select some rows based on a criteria, i was wondering is it faster if i create a dataview (based on the criteria) and then loop through the view? or should i loop through the entire datatable and check the criteria manually.
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Aug 2, 2010
I have a page which lists all the files in a particular folder (all PDFs), using a data-table and gridview. I'm currently sorting this table by the filename (by using a dataview), which isn't that helpful, and I want the gridview of files sorted by the file created or file modified date (as recorded in Windows). If that's not possible, a second option would be to extract the date from the file name string (no problem doing that), and sort the dataview/datatable or gridview based on that.
[Code]...
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Mar 23, 2010
1. Can someone show me sample codes on how to do that ?
2. I encountered a problem with the INSERT sql statement. I keep receiving syntax error in insert statement exception. Is there anything wrong with the statement ?
[code]...
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Aug 19, 2010
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
[Code]...
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Feb 24, 2012
After inserting an user control and double clicking on it, a stub with the default event should appear.
If I don't define what the default event is and I don't assign any attributes to any events or properties, it works, and it generates the stub for the UserControl.Load event (the default default event).
But if I set some attributes for the properties and events and/or I define the default event, the stub generated is corrupted. Here is an example of what I should get:
Private Sub FaceSelector_OnSelect(SelectedObjects As System.Collections.ObjectModel.Collection(Of Object)) Handles FaceSelector.OnSelect
End Sub
And this is what I actually get: Private Sub SketchSelector_OnSelect( SelectedObjects As System.Collections.ObjectModel.Collection`1)
End Sub
Private Sub FaceSelector_OnSelect( SelectedObjects As System.Collections.ObjectModel.Collection`1)
End Sub
In this case I had 5 user controls, I double clicked on one of them, and I got 2 corrupted stubs.
Sometimes the corrupted stubs are generated when I change some properties of other controls in the form, or the form itself. For example I resize the form, the error window doesn't show any errors, hit F5 to compile and run, and get a syntax error.
I tried to track the problem down by removing each event/property attribute/xml description, one by one, many times I thought I found the culprit, but after 10 minutes the problem popped up again.
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Jan 5, 2012
I got a problem with dataview that get data from datatabel (Col1 : ID,Col2: Time) and I'm sorting by Time in desc ... when the values for example {40.21,80.21,70.25,25.2} the dataview sorting them as I need but when one of values goes above 100 for example {40.21,80.21,100.25,25.2} the dataview always sort the highest number is the buttom, I don't know why ..
This is a sample code
Dim dt As New DataTable
dt.Columns.Add("ID")
dt.Columns.Add("Time")
[CODE]...
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Sep 7, 2009
I've got a textbox with a mousehover event and that event will only happen once and then I have to move my mouse out of the text box before it'll happen again. Is there a way to reset the mousehover event 'trigger' so that it happens as many times as I want?
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Jul 6, 2009
I'm trying to reset a form after a game has been played. I used checkboxes to indicate when the user picked a particular line item to update and then flagged the checkbox as checked and disabled.Once all the checkboxes have been checked, the game is over and I want to show a dialog (msgbox) that will allow the user to start a new game or exit the app. To reset the form, I was changing all the checkstates back to unchecked (along with resetting other variables), but the checkchanged events are being triggered and I end up in a loop.Is there a way to change the checkstate without triggering the event?[code]....
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Jan 6, 2012
I can't seem to get a DataTable filled.url...I'm using VB, Visual Studio 2010.I keep getting an error on this line: adapter.Fill(dt)The Microsoft Jet database engine could not find the object 'Book1.txt'.Make sure the object exists and that you spell its name and the path name correctly.The name of the file and the path should be perfectly fine, although i did change the code just a bit:[code]I read somewhere that you have to 'drag a data adapter object from the Toolbox onto a form or component'.I don't have a DataAdapter in my Toolbox.I did a right-click and selected 'Choose Items.It is nowhere on the .NET Framework Components.
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