Serialize A Data Table In .net?
Apr 19, 2012
I'm trying to serialize a data table in vb.net:
Dim dt As New System.Data.DataTable
and for the serializer:
Dim js As JavaScriptSerializer = New JavaScriptSerializer()
dim jsonString as string
jsonString=js.serialize(dt)
when it serialize the data table on the last line,it got an error:
An unhandled exception of type 'System.InvalidOperationException' occurred in System.Web.Extensions.dll Additional information: A circular reference was detected while serializing an object of type 'System.Globalization.CultureInfo'I even make the simplest datatable with only 1 column and 1 row, but it just won't serialize it?
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Jan 26, 2012
I am trying to write a class to serialize/deserialize something as simple as:
<table border="1">
<tr>
<td>row 1, cell 1</td>
[Code]....
I just can't get it to serialize to this thing. I tried to generate the class using xsd but that produced a lot of garbage code and I really would like to maintain this by hand as it is easier than the monstrosity that xsd produced which didn't work anyway.
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Aug 17, 2010
If a class is serialized and has events fired from it that are handled on a form you get the error "Form1 cannot be serialized" in c# you can use (to work around this):
[Code]....
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Jun 11, 2009
I'm trying to serialize/deserialize data in vb. I've made a .dat file from a blank plain text file (not sure if this is suitable) which seems to connect ok, as do both the classes. Here's the
Imports Microsoft.VisualBasic.ControlChars
Imports System.IO
Imports System.Runtime.Serialization.Formatters.Binary
[Code]....
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Feb 9, 2010
I have searched for an answer for a long time now, both generally ont he web and in several forums including this one. There are many people who asks this or similar qusetions, but the answers are often hard to understand, and quite often are answers to something other than what was asked from the beginning.I know that there are many skilled programmers out there, but most are not great teachers. So here is what I need: I have constructed a program in which the user can write values in textboxes, choose from lists (comboboxes) and make some choices by checking checkboxes. The data in the lists comes from a database, but I don't think that is really relevant here. What I want is, when all the choices are made and when the textboxes, comboboxes and so on have data (text or numbers) in them, I want the user to be able to save this to a file (XML perhaps?).
To speak plainly and visualize this to you, think of a roleplaying game (RPG), and that you fill out a character form with details about your character. Of course you want to save all this, and at some point retrieve it to make changes when you level up. I am not all that stupid when it comes to programming, but I have never tried to do something like this. My applications have had a database engin behind the GUI, and all the saving was done in tables at the far end of everything. Now I want to save data to a file instead. I have tried to find books (or a good tutorial here on the web), but most answers are for C (++. #, etc), or else they are hard to understand.
Is there anyone here who can help me or point me in the right direction? I'm not asking you to do my work for me, but som examples that are valid and that will help me understand the process whould be nice. So far I have recieved good help here on this forum from nice people.
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Feb 26, 2011
I have a list with class user and I am able to serialize the data and save it to an xml file. However I just cannot figure out how I
can deserialize that .xml file and save the data into a new list.
The following is my code:
Dim Users As New List(Of User)
Dim objStreamWriter As New StreamWriter(filelocation)
For Each btn As Button In myNodeBtns
[Code]....
I want to read the data back from the file and save it into the mynodebtns list where I orginally took it from.
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Jun 1, 2009
I've got a web app that sends a request to a WCF service. The WCF service gets a LINQ resultset (anon. ilist) and sends that in reply, back to the web app.In order to get it working quickly, inside the WCF app, i'm using copytodatatable and sending it to my web app in a DataSet.
My web app then takes the DataSet and writes it to xml, some xslt is performed and the resulting data is shown on screen. Perfect.
I'm still (relatively) new to WCF. I understand that sending DataTables/DataSets is a bit cumbersome. The web app wants the data in xml format (for the xslt operation), so I figured I'd get the WCF web service to do the DataTable -> xml work for me, and simply reply with a nice XmlDocument to the client webapp.However a XmlDocument cannot be serialized.
What's the best way of sending the XML data down to the client over wcf?
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Jan 15, 2010
I'm trying to serialize a data structure and pass it to another report via parameter, and this line of code:
Dim s As New System.Xml.Serialization.XmlSerializer(GetType(System.Collections.HashTable))
Produces this error:
An error occurred during local report processing. The definition of the report '/myReport' is invalid. There is an error on line 22 of custom code: [BC30002] Type 'System.Xml.Serialization.XmlSerializer' is not defined.
How can I get around this? I have been able to use fully defined .NET classes in other lines of code, including the following:
Dim outStream As New System.IO.StringWriter()
and
Private colorMapping As New System.Collections.Hashtable()
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Jan 20, 2011
I have three table and I want to put the three table's data in one variable and from that variable i will produce the datatable and then want to write the data in CSV file.I am Following this step..
Void
GetDetails()
DataClasses1DataContext
[code].....
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Dec 26, 2010
I have a login form that consists of 2 text boxes: txtUser, txtPass. Now these are not bound to any data table & I don't what them to be bound. When a new user enters his user name & password, I want to add these on a data table that has two columns: User, Pass. Data table information: Data Source = Login.accdb, Data table = LoginTable, Connection = LoginCn. I use visual basic 2010. So how do I do this?
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Apr 23, 2009
I have this code to edit the datarow of my table adapter but t doesnt update the table. I think i have a missing code that's why but i cant figured it out. by the way im using vb2008 and SQL as my database. [code]
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Jul 8, 2009
I currently have this working already for one of my combo box's, but when i try to use the same code i get this error ''There is no row at position 6.'' . The are 2 fields in the table asset_type_id, asset_type_name', im trying to dispaly the values in a combo box for the field 'asset_type_name.
the code for ' Friend Sub RetrieveCustomerInformation2()' works but the other friend sub throws the error.
Imports System.Data.SqlClient
Imports System.Data
Imports System
Imports System.Data.OleDb
[Code]...
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May 23, 2010
While am using the below code it was throwing an exception update unable to find table mapping [Customer] or data table customer.
[code]...
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Jul 7, 2011
I have 1 access database with 3 tables How do I make the combobox get data from one table and input it to another table?ex.I have a table with all my Carriers and another table with jobs that are assigned to Carriers?
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Jun 7, 2011
i have a combobox on the form and a datagrid viewer .no i want to display the table which selected on combo box..
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Feb 23, 2011
I have a form that fills a table adapter with this:
Me.Scratchpad3TableAdapter.Fill(Me.MDRDataSet.scra tchpad3
and what I'd like to do is when users edit something on this form that they post the changes to a table called exceptionsedit which is not part of that dataset. What I don't know how to do is to how to insert those edits to the exceptionsedit table.
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Mar 20, 2012
i need to copy all the rows with data from a existing table to other existing table through button click
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Feb 17, 2011
I am using Visual Studio 2008 and Sql Server 2005
I want to update a table using values from other table I have written a query but it is giving error
"Cannot insert the value NULL into column 'Quantity', table 'Stationarymgmt.dbo.Item_Master'; column does not allow nulls. UPDATE fails."
temp table has following columns
Item_Code,
Quantity,
[Code]....
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Jan 19, 2009
Currently using VB 2008 with MS Access 2003.I have Two Tables with Names - " Company_Data" & "User_Data" in which i have the following columns.....
Company_Data
Name|Age|Department|Salary
User_Data
Name|Age|Department|Updated On
Now, Is there any code that can do the following:when i select a name in the combo box on the form (The list in the combo box is from the Name in the Company_Data table) and click update.It should copy the Details of the Record from Company_Data to User_Data with the current date in "Updated on" column. Note that the columns are not exactly Same. (Salary is not necessary in the User_Data)?
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Aug 15, 2010
I want to copy Header Data from one table to another. I know how to do this if the table data is exactly the same, but I need to generate a new HeaderKey for the destination table.Example - I am copying SalesOrder Header Data into the PickList Header Table, but I need to also add a PickListHeaderKey when I do so. It cannot be the SalesOrderHeaderKey which will be copied also.
Source Table (Sales Order)
DestinationTable (PickListHeaderTable)
SalesOrderHeaderKey [code]....
How can I edit this command to include the PickListHeaderKey, which needs to be inserted at the same time or before the rest of the data is copied?
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Jun 10, 2011
I really need your help. I want to query in a table in MS SQL using a data in another table.This is the query I've constructed : "SELECT TABLE1.FIELD1,TABLE1.FIELD2 FROM TABLE1, TABLE2.[code]
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Feb 4, 2009
have made the data table in vb code, and it works flawlessly. It gets its values from labels which are part of a calculation.It shows the information to the user in a datagridview. Now i would like it to add new rows and fill them in if the user has already entered the data once and it has been logged in the datagridview.here is the current
'DATA TABLE
Dim Table1 As DataTable
Table1 = New DataTable("CF Log")
[code].....
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Dec 8, 2010
i want to create a table that include a current year data and as well as previous data to be compare. here is the example of the table that i want to create: but i want to compare one of the annual data with the previous year. as example i want to compare between the data of current AR of 2007 with the current AR for 2006, Current AR of 2006 with current AR for 2005 and go on~, but i have no idea how to do it.
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Aug 6, 2011
I have two data tables. the second related to the first. Using a datagridview for the first table I am able to enter and save data ok. if I run the code twice in a row the data is still there. When I edit the data in the related table in it's own datagirdview the data is there and displays correctly, but on running the code a second time the related data is lost. In both cellendedit events I am using
Me.table.Update(Me.FigsDataSet.table)
Me.Validate()
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Dec 18, 2010
I have a data logging application that stores data in a table in a MySQL database. Data with a TimeStamp is logged into the table anytime the data from the sensor changes. This means that there maybe 2 seconds between data points or there maybe 20 seconds between points depending on how the data is changing.
When I need the data I have 2 dates and use this command to fill a table..SELECT FROM myTable WHERE timeStamp > date1 AND timeStamp < date2 This gets all the data that has a TimeStamp between the given dates, but in most case the first date in the returned table will be after date1, so I need to get the data from one row before the date returned in the table to know what the data was at date1.How can I get the data row that immediately precedes the returned data set?
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Nov 11, 2010
The control comes up blank??Imports System.Data Imports System.Data.OleDb Public Class Form1
[Code]...
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Sep 28, 2009
I would like to know the best, or standard, way to accomplish real-time client updates in a small multi-user application using an access data table as a data source.Specifically, this application will be used by 3-4 people. It uses a datatable which is filled on form load and bound to a datagrid at design time. The datatable is stored on a shared drive. The data table on the shared drive is updated in two ways:
1) Users can update the datagrid which then updates the datatable on the shared drive via the data adapter's Update method.
2) A server application does some work on some text files, periodically updating the data table.
I need the clients to reflect the changes to the data table on the shared drive as closely to real-time as possible. I know that the data table stored in memory on the client is disconnected from the data table on the shared drive, so I must query again to get the updates.
1) Is there an alternvative model I can use which is connected, and which will automatically reflect the updates in the data table on the shared drive?
2) If not, what is the best way to check for changes in the data table (so I can know when to call the data adapter fill method)? I am planning to poll the drive for a change to the .mdb file, raise an event and then fill the data adapter when the event is triggered. I am using this method successfully now to check for changes to a text file in another application, and I know how to implement it?
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Sep 28, 2009
I would like to know the best, or standard, way to accomplish real-time client updates in a small multi-user application using an access data table as a data source.
Specifically, this application will be used by 3-4 people. It uses a datatable which is filled on form load and bound to a datagrid at design time. The datatable is stored on a shared drive. The data table on the shared drive is updated in two ways:
1) Users can update the datagrid which then updates the datatable on the shared drive via the data adapter's Update method.
2) A server application does some work on some text files, periodically updating the data table.
I need the clients to reflect the changes to the data table on the shared drive as closely to real-time as possible. I know that the data table stored in memory on the client is disconnected from the data table on the shared drive, so I must query again to get the updates.
I have two questions:
1) Is there an alternvative model I can use which is connected, and which will automatically reflect the updates in the data table on the shared drive?
2) If not, what is the best way to check for changes in the data table (so I can know when to call the data adapter fill method)? I am planning to poll the drive for a change to the .mdb file, raise an event and then fill the data adapter when the event is triggered. I am using this method successfully now to check for changes to a text file in another application, and I know how to implement it
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May 22, 2010
I am trying to learn the new methods in .net, but, I cant see a way to step through the data like you can in an ado recordset. I want to pull data from a table once, then split the data with a filter, then step through the rows gathering the dtata till eof. Clear the filter and reset it for the next batch.
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Sep 30, 2010
I've tried exporting data from an Access 2003 database to Excel in VB.NET using the following [code]...
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