Tell me if this is efficient code. or if there would be a more efficient way of doing this:
CODE:
I'm wondering if error catching will take more. time than a few more lines of code to accomplish the same.
How can I test my codes efficiency in vb.net?
View 1 RepliesWe have a property whose job is to look up a description. If the lookup fails it should show an empty string.
So we can code the property like this:
If foo.bar Is Not Nothing Then
Return foo.bar.Description
Else
[Code]....
But are there any problems (performance, purity, other?) with just catching and ignoring the error?
You sometimes read it's expensive to throw an exception but I am not sure whether the author means it's expensive to build in exceptions using the Throw keyword (which I am not doing) or whether he means it's expensive to allow exceptions to occur (as I would be doing).
MVC3, VB.NET, using EF. I am working on coding up a simple function to handle checking for a valid MySQL connection. If the connection fails the test it will use the secondary server connection. This is required because our hosting provider does not provide failover or redundant MySQL servers. The problem is I tried to use a simple try catch method in the HomeController. This fails early because the Entity Framework is looking the connection that was set up when I set it up... Is there anyway to control that connection dynamically?
View 1 RepliesI have a program in VB.Net that receives mails from Outlook, extracts attachments and inserts the attachments into a table through a query. I would like to put the query/queries in a Try/Catch block, but cannot do so as Outlook exceptions cannot be caught, and it gives me an error, and unless I put a very specific exception, I cannot catch it. Is there a workaround?
Edit:
Try
Catch ex As Exception
End Try
Exception is underlined and when I hover on it, it says: "Catch cannot catch type 'Microsoft.Office.Interop.Outlook.Exception' because it is not in 'System.Exception' or a class that inherits from 'System.Exception'". This is affecting all my other code which I'd like to put into a Try/Catch block.
The following code causes a "Warning" that Variable is used before value assigned.How do I restructure this Try/catch to eliminate error on the myreader.close command in the Catch part? Code appears to work fine but I dont like Warnings. [code]
View 8 Repliesi have problem when i click a ADD button, there is one null value in the textbox .. so the try catch statemnt is to catch that null value error but after that the catch is success but the button click never stop excute the statemnt till the end of the button event.
View 6 RepliesI have this scenario: in a Sub I have a Try...Catch statement.Within that Try..Catch I call another sub.In that 2nd sub is also a Try...Catch.(see below for example).Now if an exception occurs in the 2nd sub's Try...Catch, which Catch gets excecuted? The 2nd one, the 1st one or both?
Private Sub sub1()
Try
..do stuff[code].....
If I throw an exception from within a catch, does the finally (from the catch) still execute? i.e.
Try
..some code with an exception in it...
catch ex as Exception
throw new SpecialException("blah blah" & ex.Message, ex)
[code]....
I need to catch log4net exceptions (its own exceptions not app exceptions logged by it). I wish there's a way of doing it this way: [code] I have this code implemented and there's no errors in compilation but i force log4net to have an error (pointing to a non existing database in the config file) and nothing is threw.I've tried the listener aproach: [code] and it's writing the errors to log4net.txt, the forced ones i mean.This last aproach has a couple of drawbacks: it won't append every error to the file, if the error is the same it doesn't write it, i can't get the listener to write every error to that file, only one (I don't know how to fully configure the trace listener, it might be that). Thus it won't append the date and hour to every line wich is a necesity for me. Finally i can't give structure to it (xml). Even if the listener work i need to use the try/catch aproach, since i'm using ExceptionHandling from Enterprise library to log the errors in my app.
View 1 RepliesI'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.
View 10 RepliesFor 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?
View 1 RepliesSo 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.
I don't understand the error, Argument not specified for parameter 'test' of 'Public Shared Function TestThis(test As String)'.
Partial Public Class Form1
Shared Sub ReceiveCallback(ByVal ar As IAsyncResult)
Form1.Invoke(TestThis, New Object(){"test"}) 'error
[code].....
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
[CODE]....
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
[code].....
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).
View 3 Replieswhich is more efficient?(Assume case statements, etc., cannot be used.)
If a Then
If x Then
ax()
ElseIf y Then
[code]....
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).
[Code]...
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.
View 12 RepliesThis 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]...
View 1 RepliesI am using VB.NET 2005 to create a Windows forms application. I have a procedure named SendMail that creates an instance of Outlook.Application, to send an email from my application. I found the code on this forum, I think.The procedure works fine, but I can't use error handling with it.I call the procedure from a button click event. I put the procedure call in a try/catch block, and the application won't build, with the following error.
Error 68 'Catch' cannot catch type 'Microsoft.Office.Interop.Outlook.Exception' because it is not 'System.Exception' or a class that inherits from 'System.Exception'. C:datadevdmtiQTSQTSv7_1_20100212wQTSQTSReportsCriteria
pt_frmReportViewer.vb 43 21 QTS
Here is the code:
Sub SendMail(ByVal sFile As String)
' Create an Outlook application.
Dim oApp As Outlook._Application
[code]....
I have an application that queries DHCP and pulls scope/subnet information. There are roughly 8k scopes on our network to query so reporting this data takes a little bit of time. I currently have this running on it's own thread and reporting to a progress bar so the applications doesn't seem inactive.
The DHCP api functions can report a total, a max read and a resume argument. This means that I can, in theory start 4 threads and have each thread read through 2k subnets, so it will only take 1/4 of the time to read all this data. Would I need to create four separate background worker handlers, do_works, runworkcomplete, report progress etc.?
[code]...
and from VB6 project I reference to Test.dll but an error messege was appear A reference to Test.dll file could not be added (If I create VB NET project and reference to file Test.dll it OK )
I'm getting 'Catch' cannot catch type 'Object' because it is not 'System.Exception' or a class that inherits from 'System.Exception'. and 'Expression detected' Code underlined in blue: Catch obj1 As Object When (?)
Private Sub OpenJAMem()
Dim num3 As Integer
Try
[code]....
Probably a dumb question, but can you write a unit test project in one language to test against another project in a different language?I'd like to translate one of our VB assemblies into C#, but want to build unit tests to verify the results. I've tried to set a unit test project up to do this, but I can't seem to access the VB code within a unit test... I can't figure out if I'm just missing/doing something stupid, or it really isn't allowed.
View 2 RepliesI have a project converted from Visual Studio 2005 to Visual Studio 2010. It compiles and runs.
When I prune "unused references's from this project as listed by Visual Studio, the project fails to compile with the subject error message.
In particular one of the "unused refererences" is to "Microsoft.VisualBasic.dll". The IDE does not allow me to add back this particular reference.
What do I need to add back as a referenceto get this items?
A few weeks back in reply to a thread, I said then that it's sometimes worse to use a Try/Catch when there's nothing in the Catch!There are exceptions to that I'm sure, but too often the Try/Catch is used with a blank Catch that makes even the developer scratch their heads when the program crashes because they have nothing to go on (by their own doing).DevExpress (and I'm a big fan of their stuff) has a little three minute video that encapsulates that concept well and I thought that you all might enjoy watching it:[URL]
View 1 RepliesJust wondering if i might hit a snag in my program. Ive got 10+ users using the same files, via a Oledb to put info into an excel spreadsheet. If 2 or more people save there file at the same time will the program go into read only on one person. Normally one 3 will use the file at one time. I know Sql itself would be better to use. best way i can describe it, normally using excel if you manage to open the same file twice one opens as normal but the other opens as a Read only file, will the same thing happen if im using Oledb connections?
View 2 RepliesI understand how try-catch works and how try-finally works, but I find myself using those (usually) in two completely different scenarios:
try-finally (or using in C# and VB) is mostly used around some medium-sized code block that uses some resource that needs to be disposed properly.
try-catch is mostly used either
around a single statement that can fail in a very specific way or (as a catch-all) at a very high level of the application, usually directly below some user interface action.
In my experience, cases where a try-catch-finally would be appropriate, i.e., where the block in which I want to catch some particular exception is exactly the same block in which I use some disposable resource, are extremely rare. Yet, the language designers of C#, VB and Java seem to consider this to be a highly common scenario; the VB designers even think about adding catch to using.
Or am I just overly pedantic with my restrictive use of try-catch?
EDIT: To clarify: My code usually looks like this (functions unrolled for clarity):
Try
do something
Aquire Resource (e.g. get DB connection)
Try
[Code]....
which just seems to make much more sense than putting any of the two catches on the same level as finally just to avoid indentation.