I 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 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 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
if for example i have two private sub I declared a local variable on private sub a... is there a way that private sub b could use the variable created on private sub a? Im asking because im in a problem in my app were using global variable is not an option to make the long story short
View 5 RepliesIs there any official notation for private fields? Like mVar, m_var or another notation?
View 10 RepliesI am a vb.net programmer switching to C#.I have the following code for a console application (targeting NET20)
using System;
using System.IO;
using System.Data;[code]....
This is giving a compile error in the if clause of InitVars for the _dbName variable:
Error 1 An object reference is required for the non-static field, method, or property 'eScoreSwapper.Program._dbName' C:UsersSethSDocumentseScoreVersionsTrunkdotNeteScoreSwappereScoreSwapperProgram.cs 26 38 eScoreSwapper
C# does not allow you to reference private class fields unless they are declared static?
I am trying to implement transactions across multiple TableAdapters in VB.NET (using Visual Studio 2010) by extending the partial class as described in the following examples:
http://blah.winsmarts.com/2006/06/18/the-definitive-tableadapters--transactions-blog-post.aspx
madprops.org/blog/typed-datasets-and-sqltransaction/
stackoverflow.com/questions/2342289/net-tableadapter-to-dataadapter
However, when I attempt to expose any of the private fields created by the designer they are underlined in the editor with the following error:
'_adapter' is not declared. It may be inaccessible due to its protection
level.
Searching this site as well as google has not revealed anything useful, but perhpas I'm searching the wrong keywords.
Here is the code in MyDataset.vb
Partial Public Class MyTableAdapter
Public Property MyTransaction() As SqlTransaction
Get
[code]....
a simple question. Given the following code:
Public Class MyClass
Private WithEvents pPerClass As PersistableClass
Public Overridable Property PerClass() As PersistableClass
Get
Return pPerClass
[Code]...
the first being a duplication of the second key, strangely obtained from a private field.
If you remove the WithEvents keyword, the pPerClass_PersistableClassID key is not created.
I am new to EF but it seems to me a strange behaviour.
I am a little new to .NET Developing, and have learned a great deal recently, but I'm stuck with something. I come from an ASP Background, I'm trying to subtract 2 variables, but they don't seem to 'see' one another.
[Code]...
I'm trying to make an application that calls a function to create a timer, but I cant use WithEvents or Private inside of a function or sub, Is there any way to do this?
View 5 RepliesI thought I had this figured out because it presented no errors, but when i tried to run it, I got this exception error:
Object reference not set to an instance of an object.
I am trying to set two private variables:
Private mdatStart As DateTime
Private mdatEnd As DateTime
I need to set these dates from a datetimepicker (dtpPickup, dtpReturn), but I don't now how to set it. I have tried using:
Private mdatStart As DateTime = New Date(dtpPickup.Value.Year, dtpPickup.Value.Month, dtpPickup.Value.Day)
'Private mdatEnd As DateTime = New DateTime(dtpReturn.Value.Year,
[Code]....
Does anyone know how to supress the private variables from showing in the .NET Namespace? I have a Class that looks similar to this.
[Code]...
I'm trying to get a handle on creating my own Interfaces for a project I'm working on. I know the MSDN help shows that all member signatures will become Public when implmented, etc, etc. However, if I implement the IDisposable interface provided by the framework, comments and private members and fields show up! Not only that, but some of the methods have comments and code within!
How did they do that? And can comments, private fields and members, and predetermined code be declared as part of an interface by the average developer?
I am programmer from some time only, I have certain doubts in fundamentals, could you please clarify on the following:Case 1:
[Code]...
Does case 1 and case 2 yield same result, I mean is a private value necessarily in there?, can we use property itself to use its own value in its Set and get statements?
comparing C# code and VB.NET and the results between the seemingly identical code were entirely different.(Why C# is always winning over VB.NET?)The explanation given is that C# will initialize the class fields, then call the base constructor, but VB.NET does the exact opposite. Is there a technical reason for the languages to be different? At first glance, it seems that either approach is equally valid, but I can't fathom why they wouldn't have selected the SAME approach.
EDIT: As 'Jeffrey L Whitledge' has pointed out, VB6 did not have inheritance, so I don't think we can say 'to keep VB.NET and VB6 more closely related'.
I have a bunch of private variables I've typed out and I want to put all of my corresponding Public ReadOnly Properties in a bunch below them.Is there some way of copying ten lines of
Private _myVar As String
and pasting in ten sets of
Public Readonly Property MyVar As String
Get
Return _myVar[code]....
I'm currently copying the whole bunch of variable declarations, Find+Replacing Private _ into Public ReadOnly Property then going line-by-line expanding the definitions and writing return statements.how to avoid all this nonsense in the future, as I'm developing on a virtual terminal server, and the input lag on my little copy/paste/type operations on the code is driving me up the wall.
I would like to create an interface that brings with it it's own private variables and regions.for example, if you create a class and implement IDisposable, you get all of the following:[code]
View 3 Repliesgive me a good resource that explains the difference between a Private, Public, Shared Functions/Sub/Variables? I normally use Public for Subs/Functions inside of Modules I call from other parts of the program. But I'd like to get more of an understanding of how and when to use them. I want as little as impact to a system that is running my programs as possible, so i guess the key here is I'm trying to just get more proficient in my coding.
View 8 RepliesI have these list of RS-232 strings declared in my public class
Public Class TouchInterface
Dim WatchTVbtnCmd As String = "rs232command1"
Dim VolUpbtnCmd As String = "rs232command2"
Dim VolDownbtnCmd As String = "rs232command3"
Dim SystemOffbtnCmd As String = "rs232command4"
Dim RadiobtnCmd As String = "rs232command5"
Dim MusicbtnCmd As String = "rs232command6"
I then have this private sub. For the sake of this thread, what I would like to do is get the name of the label that was clicked which in the code below is already done, convert it to string (not sure if this needs to be done), this is also done in the code below. Next I want to compare the labelnamestring to all the variables in the public class to find out which one it is equal to and then disply that variable which should be my rs232 string in the message box. I have also added "Cmd" to the variable names above so I also need to work out how to add the text "Cmd" to the string to properly compare.
Private Sub Musicbtn_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles WatchTvbtn.Click, VolUpbtn.Click, VolDownbtn.Click, SystemOffbtn.Click, Radiobtn.Click, Musicbtn.Click, GardenVolUpbtn.Click, GardenVolDownbtn.Click, GardenRadiobtn.Click, GardenOffbtn.Click, GardenMusicbtn.Click, GardenMediaCenterbtn.Click
Dim labelname As Label = DirectCast(sender, Label)
[Code] .....
I have been using VB a fair bit in the past developing a Access Database, recently I wanted to give my front end interface a bit more power so I have started learning VS 2010.
Anyways, I am still using Access for my databases and i am having a bit of trouble working with the data in VS 2010, what i would like is the following:
A way to form a string or integer from a SQL query (from a single field or multiple on that row) assuming the query will always return one row.
Then a way to write string or integer variables back in to db fields.
example:
Dim cn As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|ItemRegisterDB.mdb")
Dim cmd As New OleDb.OleDbCommand With {.Connection = cn, .CommandText = "select * from tblItemregister where ItemID = 1"}
[Code]....
Example = ??? 'What would i need here to copy fields from that row to string?
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
[Code]......
I'm facing a problem with my current member card reader development.
I'm reading the card number (just a serial number of 4 digits) with a card reader. this seems to work fine (even converting the text string to integers).
This number is then put in a query to find the exact record that corresponds with this number
Me.JSM_LedenTableAdapter.GetDataByKaartnummer(IntCardNr)
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 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
[code]....
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
[Code] .....
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 Replies