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
View 6 RepliesI 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]...
I want create a datatable .In this datatable 2 coloums are percentage and marks .I want to show the maximum percentage record display on first and simultaneosly another racord ?Thats why i take a dataview but dataview could not sort the datatable exam.
Dim view As DataView = dt.DefaultView
view.Sort = "clm_percentage DESC"
dgvStudInfo.DataSource = view
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.
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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]...
I am sorting a dataview by a date/time stamp. As of right now it is sorting it oldest to newest. How might I write it to write from newest to oldest?
[code]...
I want create a datatable .In this datatable 2 coloums are percentage and marks I want to show the maximum percentage record display on first and simultaneosly another racord ?Thats why i take a dataview but dataview could not sort the datatable
exam.
Dim view As DataView = dt.DefaultView
view.Sort = "clm_percentage DESC"
dgvStudInfo.DataSource = view
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?
View 6 RepliesI 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
View 1 RepliesHow to create a dataview from a datatable?
What is the basic use of the created dataview?
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].....
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().
Does anyone know if it's possible to pad a column to the left using the RowFilter property in a DataView? My data comes from a third party via XML which I've converted to a DataSet. I'm inferring the XML schema to set the column datatype. I've converted the column in question to string in order to properly compare any text entered by the user. At the time I populate the data grid I format the column by padding it with zeros on the left side so that it is always 11 characters (Ex: 123456789 becomes 00123456789). This is for legal reasons and not optional. However when using the RowFilter property the zeros in front are obviously not accounted for because they don't exist in the DataSet.
This is what I'm doing currently:
[Code]...
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?
View 2 RepliesFor 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)
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)
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.
View 5 RepliesI have filled a datagridview with a dataset using the following code.
Code Snippet
Is there a way to get a subset of Unique values in column(1) of a DataView?
View 6 RepliesI have a dataview object that is being populated by database fields - so I can sort on these partulular columns by specifying the actual column names without any difficulty. However, I have been asked to add a few more columns to the dataview, and these columns will be calculated columns, not directly derived from an underlying database column.The users want to be able to sort on these new columns as well - even though there is no actual column name I can use to sort.
I have not been able to see where I can sort a dataview based on the actual column integer value used when the user clicks the appropriate heading to sort.
I am trying to do a search on a index/row number taken from a dataview i.e. I enter 379437 in the input box which I know has a index/row number of 6. Now when I replace the Rows(index) with a Rows(6) I get the results that I want. When I run the code below the index comes out as 75 which displays the first row from the dataset which is a completely different set of results.
[Code]...
i am trying to add several rows to a dataview before bindng it to the datagridview. I have tried several variations of the below code but only the last row will actuall load into the grid. Probably doing something stupid.
My code is:
dvInspectDetail.AllowNew = True
Dim newRow1 As DataRowView = dvInspectDetail.AddNew
newRow1("IDetail") = mDetailNo.ToString
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Looping through rows in a DataView
I have created a dataview from a datatable.
My question is how can I loop inside the dataview?
I know that in a datatable I can perform a loop like this:
For Each oRow as DataRow in iDataset.Tables("tableName")
Msgbox oRow(0).ToString
Next
How do i do that for a DataView?
I have an XML that looks like this:
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="library.xslt"?>
<Library>
[code].....
every time i run this code i get the same error
Unable to cast object of type 'System.Data.DataTable' to type 'System.Data.DataView'.
the code is
Dim plmExcelCon As New System.Data.OleDb.OleDbConnection
Dim cmdLoadExcel As System.Data.OleDb.OleDbDataAdapter
Dim PrmPathExcelFile As String
[Code]......
I have a sqlDataSource that runs a stored procedure that returns a table of the days of the month that was passed in as a parameter, arranged as they would in a calendar. It also returns a second table which contains the event details associated with certain days of the month.Basically, how would I go about accessing the values contained in the 2nd table that is returned by my query?I have tried putting the result of the .select in a dataset, unfortunately I get a cast error. If I try to put it in a dataview, I only get the first table.[code]
View 3 RepliesI have a form where I open an Access database with 3 tables. I have defined datasets and dataviews for these three tables in the main form. I want to open a new form and access and update the tables using the dataviews I've already defined. When I try to access a record from the dataview using the new form, it's not defined. Can I pass the data between forms or do I need to redefine it in the new form? This is the first time I've tried to use multiple forms.
View 6 RepliesI am trying to create a basic webpage that will check a column of a database table to see if a "UPC Code" is taken already, to prevent duplicate use. I'm fairly new at .NET programming, but have built asp pages before. I'm just stumped :/
I have a textbox that a user can type in a number. The page successfully checks to see if the textbox is blank and reports the error, and if there is a value, it's supposed to bind that textbox number to a gridview to see which Item# it's associated with. But for some reason, my code is not binding the value of the textbox to the gridview.
Code:
<%@ Page Title="Home Page" Language="vb" MasterPageFile="~/Site.Master" AutoEventWireup="false"
CodeBehind="Default.aspx.vb" Inherits="UPC_Checker._Default" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
[code]....
I have the following code, I just want to create a dataset add some records and display it.
Make the DataSet.
Dim scores_dataset As New DataSet("Scores")
' Make the Students table.
Dim students_table As DataTable = scores_dataset.Tables.Add("Students"
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I have a form which is primarily pulled from Table1. Table1.fieldA is an integer representing a project phase. In the current Access display the form displays not the integer, but a String stored in Table2 that holds integer/String pairs representing all the phases.I'm trying to figure out the best way to reproduce this in my .NET formview. I could write code that would parse the int and display text, then reverse the process at save or insert, however then the code has to be updated if a new phase is added to the database. draw the String values from Table2 while preserving the binding to Table1 but I haven't figured out how.
View 6 Replies