I as part of the support VB code for a larger ASP project, I need to read back the existing data from an Access database, to see if user has changed a value.
I'm reading the existing data back into a DataView using the following function:
Public Shared Function GetPolicyStatus(ByVal intPolicyID As Integer) As DataView
Dim strConString As String
Dim conMyData As OleDbConnection
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I am learning visual basic .net and I am attempting to translate some java source code to a vb.net project. The project reads mp3 details and then splits the file accurately according to the frameheader details etc.
View 2 RepliesLast year (2010) I came across a FANTASTIC command that allowed me to take a string of variables with a common delimiter and break it all back out into separate variables (possibly an array) with one statement.
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As long as the delimiter was a unique specifiable character, this one-statement command could break it out into elements. my memory and point me in the right direction.
I need to be able to start with Form1, move to LoginForm, then back to Form1 taking 2 variables and the "values" they have in the LoginForm back to Form1 and using the variables. I start with the main form (Form1) and have the user enter some information. Once they click OK I have the LoginForm open. After they enter their credentials I will check to make sure they are legal users, then go back to Form1 (here is where I need to take the Username and Password with me) to log onto a server using the same credentails from the login form.
View 1 RepliesI have a search page with a couple of pulldowns. Dependig on the values of them I show a grid matching the searched criteria, basically a table with links the user can navigate to. My problem comes when the user wants to navigate back. At the moment I have a "Back" button which simply redirects the user to the initial search page. I think it would be a good improvement to have the values of the pulldowns filled in with the values the user selected, this way when he presses the "Back" button he would not have to restart the whole search process again.
View 5 RepliesQuestion 1: What is the difference between "Background Worker" and "Worker Pool" as indicated within the MSDN samples provided.
Question 2: I noticed while using, AddressOf _Function_, variables cannot be passed; what would be an efficient solution to this?
Question 3: While using multithreading is it required to invoke before setting variables, or only form properties?
Question 4: While using System.Net.Sockets is it safe/efficient to use Application.DoEvents while waiting for new data; or would be using a Do While loop be fine without DoEvents since the action would be multithreaded? Note: there can be up to 2000-3000 sockets in use at a time.
I need to set a select back to it's default value after it's been changed based on certain conditions.
View 2 RepliesI am creating an xml file with LINQ as follows...
Public Sub CreateXml()
Dim db As New MDataContext
Dim Customers = <gallery columns="3" rows="3">
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Could i mix local values with the ones returned from the LINQ query...Something like the following?
Public Sub CreateXml(ByVal **Col** As String, ByVal **Row** As String)
Dim db As New MDataContext
Dim Customers = <gallery columns="& **Col** &" rows="& **Row** &">
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When you declare a local variable (inside a method), is it automatically disposed when the method ends? Or should I still use variable.Dispose() ?
View 16 RepliesI am using a lot of variables in my code and like to have them listed or printed. How can I do that?
View 3 RepliesI am a Visual Basic 2008 user (under Visual Studio 2008) and I have numerous local variables in my project. How can I list them to a file or to a printer?
View 2 RepliesIs it possible to get the name of a local variable from a reference to the variable? For example, I can get the names and values of a calling function's parameters like this:
Dim frame As New StackFrame(1)
Dim pInfos() As ParameterInfo = frame.GetMethod().GetParameters()
Is there some way to get the same information for a calling function's local variables? This is kind of what I have in mind:
Sub SomeSub()
Dim count As Integer = 10
Dim average As Single = 45.67
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I was reviewing the MSDN documentation on VB.Net's little-used Static keyword for local variables. My question is not about how Static works (I personally plan to avoid using it as it seems like it could cause grief to future programmers who don't notice the side-effects.) My question is about this statement in the docs:[code]So can anyone interpret the above statement for me in a way that makes sense? Or is this a bug in the documentation? It's been there since the VS 2005 version of the docs and is still present in the Visual Studio 11 version.
View 2 RepliesI am wondering if you have a class and in the class you have a function which executes a sqlcommand. Which would u use ? the local variable declaration or the private member command variable.Assuming that the class has a private field called m_Cmd as OracleCommand..i am using oracle db so i use oraclecommand , if sql server then it should be sqlCommand.[code]
View 3 Replieswhen an exception occures, I want to save the data available on the stack and log it. how can I serialize all the available local variables and save them?
View 1 RepliesFor my application, I have a page that redirects to another page (within the same application) via Server.Transfer. I need to do this because the original page has an object that I need to access by using the Page.PreviousPage property.
Once my "destination" page has been fully loaded, a local deep clone that I made of the source page's object is suddenly released from memory once I perform a postback? Is this by design--something to do with the Server.Transfer?
Page1.aspx:
Public Structure myCustomObject
Implements ICloneable
Dim someField as String = "default value" ' Default value
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At this point, EVERYTHING works as it should. Stuff got cloned over correctly and all is well.(Let's say this is on a button click event) Debug.Write(newObj.someField) ' Output: "default value"<- This is NOT "changed value from source page" for some reason when it was working literally a few lines ago! My guess is that the Server.Transfer stops any association with the source page after the new page loads.
When I want to maintain code readability and keep things neat. I would create temp variables . Below is one of my functions that uses it. Is it a bad practice? I would create temp variables cost more memory ?
Private sub test(byref transac as transaction , byref txntime as string )
Dim cmd as OracleCommand = nothing
Dim Adapter As OracleDataAdapter = nothing
Dim SQLStr As New StringBuilder
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I have a page that redirects to another page (within the same application) via Server.Transfer. I need to do this because the original page has an object that I need to access by using the Page.PreviousPage property
View 1 RepliesI came across a number of new Private Shared variables (of type Hashtables(Of String), initialized in the declaration) added to a partial class for a very large (DataContext-derived) class. This seems sensible to me in one sense because they never change, and making these shared variables ensures that they won't get re-initialized every time a function is called. However, these variables are only used within the scope of one function in the class, and I fear the private namespace of this DataContext-derived class is getting rather polluted, and having these sorts of things exposed at such a high level might be confusing to others reading the code in the future.
Would there be negative performance impact to making these local variables within the function where they are used, or is there some better way to handle this? Basically we are using these 3 hashtables to determine whether anything within particular subsets of properties changed (using GetModifiedMembers and then using the Overlaps function of the hashset to see if any of the modified members correspond to members we care about).
Edit: I caved and took the time to write my own test program, which confirmed that there is a cost to using local variables (which I assume applies generally to all cases -- I doubt there's any case where a shared variable would be slower unless using the shared variable requires some additional logic to do so properly): [Code]
So in this particular case, using the local variable costs about 200%. But in most cases (including my own), the time is probably negligible compared to the overall task. So I guess the question now becomes, how do people generally feel about improving code maintainability at the cost of negligible but known performance impacts?
I just recently learned about the uses of static local variables in VB.NET and wondered about it's potential use in lazy loading properties.
Consider the following example code.
Public Class Foo
Implements IFoo
End Class
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As far as i can see, this has a few advantages over the usual implementation, primary your inability to access the variable outside of the property, as well as not having to use an additional variable.
My question to you is: Which of those is the "right" way to do it? I know that static variables have additional overhead, but is it bad enough to create, in my personal opinion, unclearer code that can be misused easier? How much performance do you lose compared to the "traditional" method? How does it matter for small classes compared to huge factories?
i have a from with a treeview and a webbrowser control and three buttons. i want the back button to load the previous viewed html file from myresources and the same but opposite for forward?... also how can i and where can i link my external css to my program like my.resources so when i export the program for installing on another machine it still works? and one more thing... how can i intergrate/embed the webbrowser control into my program because as i believe it uses internet explorer and if someone installs my program onto their computer and they have un-installed ie and use firefox it won't work?
View 1 RepliesI need to get data from reports fields to open others windows forms or other reports, How I can get the values of reports fields to pass to local C# o VB.net variables? After many time ... With this upgrade making click on any Textobject on the Report the ClickPage event fire and in that sub is possible to get the Textobject data. You have to upgrade to Crystal Report 2008 SP 3.6, Link below [URL]
Private Sub crViewer_ClickPage(ByVal sender As Object, ByVal e As CrystalDecisions.Windows.Forms.PageMouseEventArgs) Handles crViewer.ClickPage
If Not IsNothing(e.ObjectInfo.Text) Then
Clipboard.Clear()
Clipboard.SetText(e.ObjectInfo.Text)
Me.CallBackForm(e.ObjectInfo.Name.ToUpper.Trim, e.ObjectInfo.Text)
End If
End Sub
Will the list in this shared method keep its state throughout the life of the method? Or will a new list be created every time this method is called?
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Im trying to build an error-logger that loggs running values that is active in the function that caused the error. (just for fun so its not a critical problem)When going in break-mode and looking at the locals-tab and autos-tab you can see all active variables (name, type and value), it would be useful to get hold of that for logging purposes when an error occur and on some other occasions.For my example, I just want to find all local variables that are of type string and integer and store the name and value of them.
View 1 RepliesI have a dictionary object (let's call it _do) I am using to cache some values for use in a multi-threaded program. I have a single controlling parent thread, with a timer function _doTimer() which can kick off child threads with a new instance of class MyThreadObject in each. My parent thread has _do as a property and with each time _doTimer() gets called, it may or may not repopulate _do depending on cacheflag settings. I pass a reference to _do to each instance of MyThreadObject and those threads at some point read the values of _do but DO NOT write to it.
What I want is to ensure that the child threads do not try and read _do whilst the parent thread is writing to it. Same thing but very slightly different -> I also don't want the parent thread to write to _do whilst the child threads are reading from it. However there is no problem with 1 child thread reading the values of _do at the same time as another child thread is reading the values - so ideally I do not want each child thread to completely lock out read access, only locking out Write access.. The code is roughly like this:
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I am fairly new to vb and have created an alarm program. I have figured out how to write an xml file saving my variables. I can only save one set of variables currently. I would like to save multiple alarms to the xml and read back the xml as a list of alarms that the program is processing. Can someone lead me in the direction to calling the xml a list of alarms and how to read them into variables
maybe if i save the alarms sorted by date and time I could process them as they expire.
Why can't I get any values back when I use Linq to Sql? BHS_TimeSheet is my database table in which have some records. Model.TimeSheet is a class I create in the model. Private db As DataFactoryDataContext
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My Dad made an application which had a feature that i want, basically his programme reads the users hard drive serial number and then multiplies it by say 12 and then divides it by 7 for example. This number is then shown as a 'Authorisation Code' which the user has to email to him and then his breaks it back down to the original hard drive serial number which he sends back which is the application serial number to activate it. I want to know how to read the actual hard drive serial number or a number that every computer has so i can do the same but i have searched everywhere and cannot find any examples for VB 2008 apart from one which didn't work
View 8 RepliesUsing 2008 VB.Net trying to do serial communications. I have a Scantron scanner I can send data to it, but I can not get read data back sent to my serial port. I have tried ReadLine, ReadByte, etc. but i'm not capturing anything, and I don't understand the DataReceived event. [Code]
View 15 Repliesi want to type in a name to a textbox like type in "Ben" to textbox1. Then i want to click a button and have correlating numbers, say 126 show up in the textbox2. Im using a function to do this, how would i write a function that takes the string in textbox1, goes through each letter and sends back a numerical value for the letter through the function. I know how to do this with text files with stream reader, but don't know how to do this with strings.
View 5 Replies