IDataReader To Delimited String Function Efficiency?
Nov 16, 2009
I have a function that I use to export the contents of anything that implements IDataReader into delimited string (that I can then write to disk or send to a response stream). It works, and it's quick for smaller recordsets but gets bogged down once the record counts get over a thousand (I have something that does the same thing only it writes to a new Excel spreadsheet and it runs in about 25% of the time). I understand that with record sets that are very large, this could cause a memory issue since I'm reading it into a string, but typically these won't be any larger than 100k (if written out to disk). My question is, here's my function, is there anything you can spot that I could do more efficiently (like, I suppose I could stream line by line to the response in asp.net, or line by line to the file on a console app, I haven't tried that).
I am getting this error when I am tring to load string type to data table)
Using connection As New SqlConnection("connectionstring;") connection.Open() Using Command As New SqlCommand("SELECT ClientId,forename,surname from t_clientdetails
I want to read a tab delimited file so i set up a data reader with the following connection string: [Code] However when I do this it doesn't seem to delimiter at the tab characters (I cannot work out why it is breaking up the data where it is). the first few lines of the csv are in the attached "dbamstr.txt" - the select statement I am running is: "SELECT * FROM dbamstr.txt".
Is there a more elegant way to structure the following code, which takes a comma delimited string containing certain values in specific positions and assigns the values to the properties of an object?[code]...
In our application we use IDataReader which actually call function from one.dll where weExecureDataReader() We have many calls in application and in some places For some reason I am getting error message "DataReader already open" but I am not sure where.What will happend if I simple close that conection in the that .dll? Am I going to make trouble to database because one datareader left opened? I assume closing connection will close reader too and gargage collector will manage that left opened datareader..
So i'm new to working with vba in access and i'm having trouble getting this code to work. What it is suppose to do is take a selected text file and read the original file into a list box. Then there is a second button that when pressed will convert the text file from a pipe delimited file into a tab delimited file and then show the changed file into a new listbox.
Option Compare Database Option Explicit Function GetFilenameFromPath(ByVal strPath As String) As String
I've started using .Net's stack collection. The basic features I guess are the "pop" and "push", where you add or take off the top element of the stack (if you are referencing other elements in the stack then another collection type is probably better).[URL]..it appears that the Stack collection (like other collections) is basically an array with some window dressing (so you actually can see other elements). As far as I can tell, "popping" and "pushing" is changing the first element of the array. Shouldn't instead the final element be the "top" of the stack and be the one that is changed? Otherwise the program has to reindex all the other elements in the array every time a pop or push is made. This seems very inefficient. But this is what Microsoft's description appears to be saying what is happening.
For example, when the codes are compiled, will VB.NET tend to be slower than C#? Or are there any major features in VB.NET / C# that we cannot find in the other language?
So i am working on a program that needs to run NSLookup for a Computer name specified by the user. Here is the code I have developed which works:[code]Now because of the dynamic domains that this will be on, it is difficult to nail down which character to start a read at to determine if the Computer name exists. For some reason the reader is not picking up the '***Non-existent' line that is reported from NSLookup. When i run the NSLookup it requires me to run the Function 2x before it displays a result in my lblresults. With that pre-knowledge,
1. How do i make the NSLookup Process more efficient?
2. Is there a better way to Parse the information to specificly pull the lines that have been reported back, specificly the '***Non-existent' line.
How would you go about reducing the code for this but still allowing it to work the way it is now
Dim updatelesson As String = cmbChange.SelectedIndex Dim chosenlesson As String = cmbSession.SelectedIndex Dim changed As String = lstNames.SelectedItem
wondering about the relatively efficiency of declaring oop variables in the loops, emselves, or declaring them before first use. Here are some examples:Declare early:
Dim ix As Integer Dim currentNode As System.Xml.XmlNode For ix = 1 To 100
I'm looking for advice/ideas in regards to ongoing file encryption.I have an event that fires frequently that contains small amounts of data passed through the eventargs.This data is then written out to disk (currently unencrypted).I need to encrypt this data (which, I can do).My attempt in the first five minutes was unencrypting the file, appending the data and reencrypting the file.This obviously works, but is pretty inefficient and not going to be my solution since the file could grow rather large and the resources to unecrypt/ encrypt grow larger as the file grows larger.My next thought was to encrypt each set of data as it's written out and have some kind of marker in the file to denote where to split so I could unencrypt each chunk to reproduce the original file.I'm leaning towards this approach now (though by encrypting small chunks of data multiple times, the file size will be considerably larger.As an example, if I encrypt each letter of the alphabet the file is approx 8 times larger than if I encrypted a string with all of the letters of the alphabet in this case each files decrypted content would be identitcal).
Some programs implement command parameters, Like my favourite computer game - Crysis - has them and windows media player has them.But how could i implement them in VB.NET..I want to have a component of my program built as a seperate exe - so it can be an Optional component.But of course the seperate exe, on load, needs data passing to it.So i need something like Process.start("Componentname.exe", "/StartDL <Suchandsuchastring>)/StartDL will need to call a function, and the string that it uses will be given to the function to initiate a download?
I'm building SQL statements with a bunch of values from a dataset. Obviously that gives some really long names to put inline or even in parameter. addwithvalue code so beforehand I just declare a bunch of variables with really short names and assign them to the DS's exact fields like: [code] but this way I'm putting all the data in the dataset into memory twice by copying it into a new variable, right? So I was thinking, if it's just a string variable representing a field on the dataset, why not declare it by reference so the variable is basically a handy nickname pointing to that field in the dataset.Will it even work to have a string declared by reference and connected to one value inside of a dataset? And if so, will that stop duplicating everything in memory? I forgot how to declare a variable as a reference to another variable instead of the normal way in VB.
This is more a conceptual question. Here is my current predicament; I am writing a vb.net WPF application and using the MVVM pattern (love it! maintainability is just amazingly awesome). Currently all the code is written by hand and there is no use of NHibernate or Entity Framework as the backend is an access database (due to policy I cannot use NH and EF doesn't support JET Databases, we may switch to MSSQL at some point but that may be a while from now).[code]...
The following output produces a string with no closing xml tag. m_rFlight.Layout = m_rFlight.Layout + "<G3Grid:Spots>" + Me.gvwSpots.LayoutToString() + "</G3Grid:Spots>"
