Declaring New String At Top Of Class?
Nov 23, 2009
I had a problem with CLR profiler. But it worked eventually and the results were outstanding. My app took 47 milliseconds to run before and after some adjustments CLR profiler runs in 6 miliseconds! This had to do with String values in a resource file which apparently takes a lot of time. So this got me thinking, isn't it more effective if you would declare 1 String at the top of your class and constantly change it throughout your code? Instead of creating a new String in a method when you need it.
Instead of using:
Dim text = "blalblalba"
You would do this everytime you needed a string:
text = "blalbla"
My question is... What exactly happens when you say text = ""? Does .net create a new String? It looks like you replace the text but what happens in the background? Would it be faster then declaring a new string?
View 3 Replies
ADVERTISEMENT
Feb 22, 2011
Ok, basically i have 3 different classes: one is a NormalUser, one is a SuperUser, and one is an Administrator. I have on one of my form loads an if statement like this:
If frmLogin.lstCurrentUserData(frmLogin.lstCurrentUserData.Count - 1).Contains("Normal") Then
Dim player As New NormalUser
[Code]....
So based on an item in a list, i want to create a new instance of that class to be my player. now i know that code doesn't work, because the variable is only present within the if statement. my question is, how can i declare "player" as a new instance of the correct type, and still be able to access it in other subs?
View 10 Replies
Mar 5, 2010
What's the proper way to declare variables in a class? I've been doing something like:
'in a class
public shared teststring As String = "first"
'on a code behind
[Code]....
with shared variables loading a second window or reloading the page (without clicking the button) renders the hello world string. so how do I declare variables in a class but make it per instance?
View 5 Replies
Mar 30, 2011
I'm trying to develop a class in VB .NET in order to manage a language globalization stored in a database and editable by the user.What I need is to know what kind of class I need to declare in order to use it without declaring a new object. For example, the way My.Settings is used.
One of the goals is that in some project the developer imports the reference and after that access directly to a property. For example: My.CustomLanguage.GetWord("Hello") without declaring objects.
Is this possible? And if it's what is the best way to aproach it?
View 3 Replies
Apr 5, 2011
I have a class that I would like to link at construction to a given control (say a textbox)
I know I can put a variable into a subroutine referentially but is there a way to store it in the same capacity?
View 1 Replies
Oct 20, 2008
I've decided to forget the d@mned custom code because everything I do with comes up with errors I don't know how to fix and it seems no one else does either. Or they do and they're keeping to themselves.
I put the functions that I needed to use in a class called MsgBoxOperations. The file name is MsgBoxOperations.vb In the report, up on the standard bar where file, edit, view, and all the other stuff is, is one that says report. You click that and go to report properties and it brings up where you can name the report and put in custom code...(hate custom code right now...) and where you can put references and class instances. Clicking on the Reference tab brings up wher you put in your references and classes.
In the classes area it asks for the Class Name, which I put in MsgBoxOperations, and the instance name of that class, this case mbo. I get that far and put in those two things and save it. Then I go to the textboxes where the values need to be. I put in the text box: =Code.mbo.GetStartDate
I've already tried taking the Code. part out and it screams that mbo isn't declared. So it does have to be there. I go to run the code and comes up with this error: QuoteError in class instance declaration for class MsgBoxOperations: [BC30002] Type 'MsgBoxOperations' is not defined.
I've posted before and still have received no help or someone tried to help but then stopped when their suggestion failed and then no one else wanted to help. I've googled this problem to the point where every link that it comes up with I have already clicked and found their information useless. I've got a freaking migraine because of this issue and have been in tears over it more than once.
View 14 Replies
Jun 28, 2009
how do i use a class without first declaring an instance of it with the new keyword?i have a class items that has a function toArray.how can i call it this way:
View 1 Replies
Aug 5, 2010
I have a base class foo that will be used in multiple child classes of similar but slightly different function:
Public MustInherit Class foo
Public Function bar1() as Something
''// Perfectly OK to change what this method does
[code]....
How do I get the compiler to generate an error when bar2() is overridden by a child class?
View 2 Replies
Jan 6, 2011
Is it possible for a class of exposing a type for function returns, without allowing users of that class to create variables of that type? A couple usage scenarios:A Fluent interface on a large class; a statement like "foo=bar.WithX(5).WithY(9).WithZ(19);" would be inefficient if it had to create three new instances of the class, but could be much more efficient if the WithX could create one instance, and the other statements could simply use it.A class may wish to support a statement like "foo[19].x = 9;" even when foo itself isn't an array, and does not hold the data in class instances that can be exposed to the public; one way to do that is to have foo[19] return a struct which holds a reference to 'foo' and the value '19', and has a member property 'x' which could call "foo.SetXValue(19, 9);" Such a struct could have a conversion operator to convert itself to the "apparent" type of foo[19].In both of these scenarios, storing the value returned by a method or property into a variable and then using it more than once would cause strange behavior. It would be desirable if the designer of the class exposing such methods or properties could ensure that callers wouldn't be able to use them more than once. Is there any practical way to accomplish that?In formulating a question, it's difficult sometimes to draw the line between complicated usage cases, and simpler usage cases which aren't quite so important. Here's another usage case, and one closer to the one I'd be most interested in (though I'm also interested in Fluent chaining; being able to have something behave like a C++ reference to a value type would be nice, but probably too much work to bother with).I have a type which is somewhat like the Windows registry, in that it is a hierarchical collection of items, each of which may have a string value, an integer value, and/or a nested collection of items. I wish to be able to support the following types of usage:[code]As for the Fluent interface, my thought would be to have the WithXXX properties return a new instance of a derived class which shadows (not overrides!) the WithXXX properties with versions that simply modify the current instance. The return object from WithXXX would be known to be of the derived class, and would thus use the shadowed WithXXX methods, but once it was assigned to a variable, it would be regarded as an instance of the base class, so the next WithXXX would create a new instance.
C++ a stronger concept of value types than C# or vb.net, including the very useful concept of references to value types; it ensures that references to value types cannot be persisted outside the scope of the type in question. Unsafe code in C# can use pointers to value types, but they don't have the protections offered by C++ references.
View 3 Replies
Sep 26, 2011
I have a collection of objects (classes I created), and each one ties to a record in a database. I want an easy way to update the information, so I thought about declaring a record in the class, that would tie to the record on the database. However, I'm having a problem updating it now.
1) Can I declare a global variable for the data context, and leave it open the entire time the program is running? This would solve my problem, but I don't know if I can do that.
2) If not, besides coming up with a complicated class to do this, is there an easier way? Here is an example of what I am trying to do:
VB.NET
Public C as Record
Public Sub GetValue()
Dim SQL As New DBDataContext
Dim X = From T in SQL.Records Select T
[Code] .....
View 1 Replies
Jun 18, 2010
In the middle of attaching a Google Custom Search Engine onto my page,I have a string which I would declare in C# as
String rxPattern = "<(?>"[^"]"|'[^']'|[^'">])*>";
How do I convert it to a string in VB?I mean store the same value into the string variable rxPattern using VB/VB.NET?
View 1 Replies
Jun 27, 2011
I'm writing a class that represents a diagram (an image). Within that class, there is textbox class. That is, each diagram can have any number of textboxes on it. I want each instance of the textbox class to have access to the members of its parent diagram class. Specifically, I would like each textbox class to be able to access the instance of the Drawing.Graphics object located in the parent Diagram, so it can handle the drawing of itself
View 5 Replies
Mar 29, 2012
if this silly but I am trying to declare a string variable by the following line
[Code]...
View 2 Replies
Jan 17, 2012
I have a String variable in this page named "a".I wanted the scenario to be.When the page is started "a" will be null.But when the user selected an entry from the DetailView Control "a" will become "have".The following is my code. But i keep getting "a" = null even though i have selected an entry from the detailView control.[code]
View 2 Replies
Nov 20, 2009
do you also have to use StringBuilder when declaring a String like this?:
View 11 Replies
Mar 10, 2011
I'm trying to return an array of strings from a function, and got surprised by an error.
I would have expected this to work, but it produces an error:
Public Function TestError() As String()
Return {"foo", "bar"}
End Function
[Code]....
I guess I'm unclear on the meaning of the {}'s - is there a way to implicitly return a string array without explicitly creating & initializing it?
View 3 Replies
Nov 27, 2011
I have a problem involving late binding, and I absolutely cannot for the life of me figure out how to fix it. I have spent hours researching the problem to no avail, so I am turning to stackoverflow as a last resort.The problem is pretty much this: I am creating a grocery list application. I have a class named Item which stores the name, price, quantity, and description of an item on the grocery list. I have a module named ListCollection which defines a Collection of Item objects. I have created an Edit form which will automatically display the currently selected ListCollection item properties, but whenever I attempt to fill the text boxes, it tells me that Option Strict disallows late binding. I COULD take the easy route and disable Option Strict, but I'd prefer to figure out what the problem is so I know for future reference.I shall paste pertinent code here. (Late binding error is in EditItem.vb)
[code]...
I have tried declaring a String variable and assigning the Item property to that, and I have also tried grabbing the value directly from the List item (not using the Get function), and neither of these made a difference.
View 1 Replies
Mar 12, 2010
What is the difference between using the 'array' class in VB and just declaring an array like normal. In other words, what is the difference between:
Dim numOfTicketsPerDay As Array
Dim intNumOfTicketsPerDay(6)
As Integer
Is there any preference of when one should be used over another?
View 2 Replies
Aug 5, 2009
How would I go about dynamically declaring a constant? (It's value is dynamic, not the variable name)
View 5 Replies
Oct 5, 2009
If you want a instance of an object to be created when a form loads or another class is created, you have two options:
Public class example
private IAmAObject As IAmAObject
public sub new()
[CODE]...
Or like this:
public class example
private IAmAObject as new IAmAObject
public sub new()
[CODE]...
I always use the first one. It's more type work but I think it's neater. How about you people and is there any real difference between the two?
View 4 Replies
Oct 5, 2010
class
eg: dim classobj = xyz("CLASS_NAME") ' where classname is a valid class name
and dynamically raising a known method of that class on that newly created object or class reference.
[code].....
View 4 Replies
Feb 21, 2009
Whats the function for converting a string that contains a class, into a class?for example
Public Class Desk
Public GetVar=1
End Class
Dim T = "Desk"
Dim Furniture = New T
What do I have to do to T to make it into a class from a string?
View 3 Replies
Mar 20, 2011
System.Collections.Specialized contains StringDictionary
[url]...
What's difference with Strong Typed Dictionary in Generics?
View 1 Replies
Apr 13, 2010
I have a question regarding the some data which is being transfered from one form to my class. It's not going quite the way i'd like to , so I figured maybe there is someone who could help me.
This is my code in my class
Public Class DrawableTextBox
Inherits Drawable
Dim i_testString As Integer
Private s_InsertLabel As String
Private drawFont As Font
[Code]...
I've got a form with a textbox( form1) in which the text is being inserted and passed through a buttonclick (al via properties).As you can see I've placed several traces and in the property of the class my trace works fine , however if I look in my Draw function it is already gone.
View 2 Replies
Nov 9, 2009
I have database with class names listed in string field. I want to circle thru records and call certain class.
Eg.
Data table
ID ClassName
1 ClsCreateButton
2 ClsCreatePanel
After retriving this data in dataset(ds.tblClass) I want to do next:
Dim aClass as New ds.tblClass("ClassName")
Do something with aClass...
View 2 Replies
Jul 23, 2010
I'm going to show you an example of what i mean[code]...
View 3 Replies
Mar 2, 2009
Is there any way to set max string length in a class used in a VB.NET web service so it gets into the WSDL as a maxLength attribute?
View 1 Replies
Apr 16, 2010
how to set string content as a class instance name?Example. I have an INI-class with many instances like .Path, .Width, etc. Now, i'm reading my ini-file string by string wich hase been written by template:
[code...]
I would like to automate reading an assignment at ONCE. Like cutting the first word in line and setup it as my INI-class instance name.I know how to cut first word, but have no idea, how to set this string as instance name.
View 14 Replies
Nov 16, 2010
I have a function that updates a Client in the database. A client object is passed in, along with a string array of fields/properties that should be updated. I need a way of accessing each property in the client object, based on what is in the array. Basically, I am looking for the VB .NET equivalent to this javascript:
var fields = ["Firstname","Lastname","DOB"];
for(field in fields)
{
[code]....
View 1 Replies
Apr 15, 2011
how find an object's type when it is a subclass of another object and I only know the string value of the object's type's name.
I created the follwing classes:
Public Class word
End Class
Public Class noun
[Code]...
Using 'TypeOf', I correctly see that pn is a properNoun, a noun and a word. The problem is, using 'GetType' to check pn against a string value, I can only see that pn is a properNoun, not that its parent classes are noun and word.
Is there a way to check pn against the string value "noun" or "word" and get back a positive result, indicating that pn is indeed a noun and a word as well as a properNoun?
View 2 Replies
