Fastest Way Of Searching For Row In A Dataset?
Dec 5, 2011
I have a program that scrap websites and "puts" the information into a table.
My problem is that now and then i get values that i already have in the table. to avoid getting duplicates i search thru the table first to see if the value exist or if the record exist but might be in need of getting updated.
My table contains 60 000 records and is growing.
first i filtered a datagrid but it takes to long so i used the "select" method on the dataset table but it takes longer.
the program loops thru thousands of websites so it'll be doing a search for every website and the added time to collect the data just takes too long.
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Jun 24, 2009
so the way I have this working now I'M using System.Collections.Generic.List(Of T) for holding 100's of a structure.Dim Users as New List(Of User)
I was wondering if there was any better way or faster list container or something like this in the .net framework?
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May 14, 2009
When I have many controls on a Form (i.e. Label, Button etc) that do almost the same thing, I often use one method to handle all the controls Click, MouseDown, MouseUp events.But to know which of the controls throwing the event and access the properties of that control I need to cast the "sender" object to the correct type.
The thing is that I always know which type it is, I don't really have to "TryCast", "DirectCast" and check if the operation returns true. I some times use CType as well.
[Code]...
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Sep 23, 2008
epeat some instructions the fastest?i tried this:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
start()
[code]....
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Jul 28, 2010
I've an arraylist having 30000 items in it, what's the best way of creating a text file on the fly from an ASP.NEt page? Currently I'm using the code below but it times out with large data,[code]
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Apr 19, 2012
I have a pixel I want to monitor for change. For example, first it is white, and suddenly it is black, and then changes back to white. My method is not fast enough to get this change.any changes I call the function below to get the original color of the pixel. Then I have a timer that runs every 1 ms to take the color of the pixel, and if it's not equal to original color; do something. For example counts the time the pixel has changed. However, this function does not run fast enough. Is there any faster methods to check the pixel? The function returns an ARGB code of the pixel color.[code]....
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Apr 29, 2012
The fastest way to generate thumbnails using VB.net and multiple computers without bogging down the UI. Right now I have 3 computers and I run an instance of my thumbnail generator code on each. One computer hosts the images. The other two computers access the folder of images via the network. My code is written to compare the main folder and a thumbnail folder to see if new thumbnails need to be generated. If so, a thread is generated and the thumbnail generation code is ran on the thread. There are 5 threads created in all. So, theoretically, across 3 machines, I'm getting 5 independent threads and I'm thinking that Windows 7 automatically spreads the load across the local cores. In an effort to avoid duplicating work, the comparison is done before the generation of each thumbnail.
This method is faster than using only one computer but drags down the performance on all computers (THE UI also becomes unresponsive). I'm looking for a better way to
1.) Produce the thumbnails as fast as possible
2.) Keep all UI's responsive (boy possibly controlling the priority setting) and
3.) Done within a single instance of the program.
In the #3, I mentioned that I would like to use one instance. Is it possible for networking information be used by the hosting computer that will allow threads to run on the other 2 computers? This way, the 15 threads will be controlled by a single host computer.
Here is a snippet of my
Public Sub CreateThumbsFUNCTION(ByVal IMAGE As String, ByVal MAXDIMENSION As Integer)
'following code resizes picture to fit.
'IMAGE needs the full path
'If thumbnail already exists, it will skip
[CODE]...
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Mar 29, 2010
I was wondering if anyone had a better(faster) way to parse a Tab delimited file in VB.net. I need to read a file into an SQL table and the file contains about 300,000+ rows. Takes quiet a while. at the moment i have the below [Code].
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Jan 19, 2012
I am quite new at VB.NET and just need helo on sorting algorithms, prferbly the fastest (quick sort) but bubble would so. It is for sorting and array for 12 numbers, which are being enter by the user via a input box. These are then transfered onto a listbox for visual aid. so the steps involved would be: (already done)1) Enter then inputs into array via inputbox2) Input to sppear in listbox (not done)3) Sort the array ascending/decending4) print results into the listbox again.In my code there is also a total and a average, but that doesnt need any help on it. [code]
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Sep 4, 2011
ive a folder with a few hundred .rtf documents. am making a program to search some text in them.the way currently im employing is having a richtextbox on my form and serially loading each file in the richtextbox and if the search text is found in it,adding it to a list.but this is time taking,
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Jul 2, 2009
In my project I have 3 different forms. They all have the same design layout so the only different you see is where the text boxes and buttons are placed. Right now I have 3 buttons at the top of each form that Im using to switch between the forms
[Code]...
I know there is probably a much better way of doing this, and faster. I dont' like the delay between each window showing/hiding. what options do I have to make this run better? Since I have the same design background is there I way I can just hide and show just the controls instead of showing/hiding the entire window?
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Apr 20, 2010
My current project is to process several files. The files come from a Unix server and have been SFTP'd to the Windows XP machine. (That's fixed protocol, I don't have control over it.) My problem now is that the Unix new line characters and Windows characters don't match. The solution is to read the file line by line and replace 0x0A with 0x0D + 0x0A, or Asc 10 with Asc 13 + Asc 10, or vbLf with vbCrLf, however you like to say it.Well I have a working function to do this, but any extra speed I could squeeze out of it would be fantastic. The text files I'm working with can reach sizes of about 100MB. So to the question:
Q: What is the fastest way to read a file in, change characters as necessary and then write the file out?Here is my current working code.
Private Sub FormatCharacters(ByVal files As String())
Try
For Each fileName As String In files
FileSystem.Rename(fileName, fileName & ".old")
[code]....
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Aug 14, 2011
When ListView is not in Virtual mode the following method seems to be the fast method to load a large list into ListView:
Dim items As New List(Of ListViewItem)
Dim alllines as String()=System.IO.File.ReadAllLines("FilePath")
For each line as string in alllines
Dim item As New ListViewItem
item.Text = line
items.Add(item)
Next
ListView1.Items.AddRange(items.ToArray())
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Sep 28, 2009
I have a search function on my company's website (based on .NET 2.0) that allows you to narrow the product catalog using up to 9 different fields. Right now, after you make your selections on the frontend I am building a dynamic query and hitting the database (SQL Server) to get the resulting list of items numbers. I would like to move away from hitting the database everytime and do all of this in memory for faster results. Basically a 3500 - 4500 row "table" with 10 columns: the item number (which could be a primary key) and the 9 attribute fields (which have repeating values for many many rows).
There can be any number of different searches between the 9 columns to get the items you want:
Column A = 'foo' AND Column D = 'bar'
Column B = 'foo' AND Column C = 'bar' AND Column I = 'me'
Column H = 'foo'
etc...
Based on my research, the .Select() function seems like the slowest way to perform the search, but it stands out to me as being the quickest and easiest way to perform the narrowing searches to get the list of item numbers:
MyDataSet.Select("Column B = 'foo' AND Column E = 'bar' AND Column I = 'me'")
In my specific case, what method I use as an alternative that has the same narrowing functionality and better performance instead of settling for the datatable.select() method?
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Nov 13, 2011
1) a text document which has content like :
uber|uber|ultra
taxi|taxi|taxi cab|cab|minicab|airport taxi|airport transfer
genitalia|genitalia|genitals
[code].....
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Mar 15, 2010
When the user clicks an "Edit" button on my form, I want a box to come up which allows the user to edit a DataTable in a strongly-typed DataSet. What's the best way to do this?
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Jan 28, 2010
I have code running in the Datatable.ColumnChanging event in my dataset. This dataset underlies a form and conventional drag/drop controls are in place for data entry.when the event triggers and runs, I am running code in the form that checks the dataset.HasChanges property. It is showing False. But this is immediately after the ColumnChanging event has been triggered.Okay, I see by others posts and MSDN that .HasChanges will only be true after moving off the row with the changed column. I have also noted lots of discussion about the advanced binding property of DataSourceUpdate Mode, but that does not address this issue.I guess I can do this by checking the state of the row for the binding source. Just seems odd that the event behind the dataset can be triggered and that does not change the dataset.HasChanges property.
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May 14, 2012
I have tried everything I can to get beyond this error which shows below as <<<<< error here. It is trying to fill a dataset from a data adapter. If I change the SELECT statement to just SELECT * FROM xTable I get the correct number of records in each table. But anytime I try with a more complex statement I get the error message shown below which indicates System.Data.Common.DbDataAdapter.Fill(DataSet dataSet. I've completely erased all data and entered a new set of test data so I know there is no problem with relationships. Each table has primary key which is foreign key in other table. IS there something wrong with the Imports section: Imports System
[Code]...
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Aug 24, 2010
i am trying to copy data from a standard Dataset to a Type Dataset (XSD) of same table structure. i want to use Automapper to do that one. So how can i do that using automapper?
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Jun 5, 2010
I need to pick all data in my application from my database and use it in my form
my question : how to pick all data in my application then i use it
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Jun 22, 2010
I have two Datagrids, One grid has all the customers garments on it with style number and contact length. The other grid has the users who have garment issued to them. the style number is in both grids. I need to loop through the users grid and say if the contract number is 1 from the first grid then the contract date on the second grid will be todays date + 365 days (year contract) I have looked at using a stored procedure and also a for each command but I am just getting stuck with it all. [Code]
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Jan 4, 2011
I have a problem saving a dataset which contains rows that i have imported from another dataset. i can successfully view the imported rows in a gridview but i cannot commit the rows back to the database.
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May 19, 2010
I have multiple datasets that I would like to combine into one. There is a common ID field that can be associated to each row. Calling Merge on the dataset will add additional rows to the dataset, but I would like to combine the additional columns. There are too many fields to do this in one query and therefore would make it unmanageable. Each individual query would be able to handle ordering to ensure the data is placed in the correct row.
For Example lets say I have two queries resulting in two datasets:
SELECT ID, colA, colB
SELECT colC, colD
The resulting dataset would look like
ID colA colB colC colD
1 a b c d
2 e f g h
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Feb 18, 2011
ok, I've finally got my test database issues sorted out, however now I need to actually modify my existing report to add the two new fields from my test database. I have made a copy of the report so that I am not modifying the original. I have deleted the two old fields and now want to add my two new fields in there. In the Field explorer window, I see an object called "dataset1" and when I expand it, it is using a view that includes fields from the table that I added my two new fields to.
The problem I see here is that I have gone in and modified the view to include these two new fields in my test database - but again, they are not showing up as selectable fields here. I am just assuming that "dataset1" is somehow pointing to the live database again and that I need to change the datasource location.In my solution explorer, I see an object called "dataset1.xsd" but the properties of that do not tell me much about where it is actually pointing to...
[Code]...
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Nov 25, 2009
I want to access data using both the datasets.
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Try
[Code]....
In my code i have dataset name ds and table named Info1,when i write ds after that how tablename is coming,its not possible? How to do that ?
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Aug 2, 2011
i am looking to map a dataset of addresses on a map. basically, i want the users to type a street name in my town and be able to see the houses that have signed up already on that street. so a pinpoint should show up on the houses that came up on the dataset.
[Code]...
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Jul 23, 2010
I have some concern about designing Datasets. I was told that it would be good to have a dataset for each table for maintenance purpose. Because frequent change in database tables is expected, having one dataset including every tables would be pain to make the corresponding change in the application.
Q. is it good approach to have a dataset for each table ( I would end up having 30~40 datasets for each db table using Stored procedure) ?
I have a separate project for commonly used datasets. each project include "dataset project" as a reference, and use it by including needed dataset into Forms, classes, etc.
Q. Does this approach makes the whole system to be slower? If I have a set of datasets as a separate project, it would be beneficial, since It will be easier to make a change (I only need to make modification in one place)
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Dec 3, 2009
it returns date, and value by date.
for ex:
01.01.2009 454
02.01.2009 785
[code].....
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Feb 26, 2010
I am having difficulties with Filling a dataset. It seems to be automatically assigning a datatype to the column based off of the first field of data it finds in that column. The column sometimes contains an integer, but it may also contain letters and numbers. If the first field is an integer, it says the fields in the column that contain a letter are DBNull. I'd like for the entire dataset to be formatted as a string/text type since I do not know what the values will be that I'm importing 100% of the time. How do I tell the dataset to expect a certain datatype for all columns and rows i'm going to import?
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Apr 16, 2010
What is the impact of creating variables using:
Dim ds as New DataSet
ds = GetActualData()
where GetActualData() also creates a New DataSet and returns it? Does the original empty DataSet that was 'New'ed just get left in the Heap?
What if this kind of code was in many places? Would that affect the ASP.NET process and cause it to recycle sooner?
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