I been learning basics of generics and it looks like it can really improve the performance of the application. But, I am not able to see the generic equivalent of Hashtable. share some sample C# code for creating generic hashtable classes. I need this for a demo.
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Consider:
Public MustInherit Class Column
Public ReadOnly Property ReturnSomethingUseful() As Object
Get
'return something useful
[code]....
But this gives the following error:
Public Overrides Function ParseValue(sValue As String) As Boolean'
cannot override 'Public Overridable Function ParseValue(sValue As String) As Object'
because they differ by their return types.
I accept that you can't do this, but I'd like to be able to preserve the semantics of what I'm. trying to do, which is to have an untyped version that deals with Object, but a typed version in derived classes that knows about the specific type T.
I like to turn Option Strict On I cant figure out how to write the generic version of this function?
Public
Shared
Sub UpdateItem(ByRef
oldValue As
[code]....
How they relate and differ from each? What are the best practices for version control? Is there a primer about publish online? Or a good book?
And is it possible to make ClickOnce and a msi in one solution of VS 2008? If so, is there any conflict or pitfall?
BTW I am using VB if that makes any difference.
We have migrated our Vb6 application to VB.NET using a third party tool. Now we are in a process of Refactoring and introducing object oriented concepts in the application.
In VB6, we were using structures in many places. As a part of introducing object oriented programming,
1. is it a good idea of changing all Structures to Classes? or Is there a concept of "Generic Structure" similar to Generic collections, Generic classes?
2. Can some one guide me any source containing guide lines or best practices for applications that are migrated to VB.NET from VB6 and implementing object oriented programmaing.
I have a Journal that records entries for different types: Journal(Of ParentT)
[Code]....
I am trying to construct a generic interface class with generic functions. My goal was to use this to implement multiple worker classes for database interaction that have the same basic functionality. Each class will deal with different object for example, category, product or supplier but unless the the functions in the interface are generic that this won't work.This is the interface code that I have but I don't know if I have done it correctly. [code]
View 2 RepliesThis code no longer works in ver 2007:' Obtain max resources available for Excel
[Code]...
Is there any way to make my programs use a lower version of net.framework other than the newest version 4 that comes with VS2010?I use my programs within a closed network and there isn't an easy way for me to install any software since I'm not the administrator.
View 3 RepliesI am trying to create a list of a generic type in vb.net 2.0 framework.
This is the generic type definition:
Public Class GenericParamMap(Of T)
Public Sub New(ByVal pParamName As String, ByVal pPropValue As T)
mParamName = pParamName
[Code]....
The compiler does not allow a "T" in the method's parameter because it's not defined, but I'm not sure how or where to define it. I thought it was okay to have a generic method definition.
I am trying to write a generic method, to avoid code duplication, which will create or activate a Form as an MDI children, based on its type. But I have to lines in error (see comments).
[Code]...
I'm trying to add functionality to my application that will disable buttons and checkboxes depending on what version the OS is when the app is launched. I made a test app to test this but unfortunately I can not get it to work. Here is my code:
'OS Check
Dim osValue As Object
osValue =
My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrent Version", "CurrentVersion", "5.2")
[Code]...
*Note - 5.2 is Windows 2003, 6.0 is Vista, 5.1 is Windows XP
I have created a license system for my application with MySql about half a year ago. What it would do is take the serial number and send it to my server if the key was correct it would return a 0 if its wrong the return value would be a 1.The problem was that when the serial number was entered correctly my program would create a "fake file" for example vb.dll in the system.And on run time my program would check for that vb.dll if the file exist it would skip my trial program and run the app as a full version. Half year later i think creating a "fake file" and checking for it on start up is extremely wrong and that's not very good security.How can i check the difference between a full version and unregistered version?
View 23 RepliesI have a XML file with the latest application version number, I have this loaded into a variable, how can i compare this against the application.info.version to see if it's the latest version??
View 3 RepliesI have a hashtable in VB.NET and I need to get the string value of a key from it's value. For example, if I do: hashtable.add("string1","string2") How would I get the value "string1" if I had "string2"?
View 2 RepliesCan you put a hashtable in another hashtable? I'm trying to make Tetris and to represent the grid of the gamefield I want to have an hashtable within another hashtable. The code is as followed
Public Tetrisfield As Hashtable
Public TetrisRow As Hashtable
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)
[Code].....
I'm using a HashTable that stores information typed by the user in textboxes on a form. There are 4 textboxes on my form including, Name, Number, account representative, and total count of things added. Besides the text boxes there are 3 buttons on the form, one or adding a record, one for deleting one, and one for display the selected name from the listbox.
Everything pretty much works for me at this point, but I just have one question. When the record is input into the listbox it is supposed to display the users name he or se just entered in the name textbox. Now then, our professor wants us to use the number for the keyString for the HashTable.
That is the problem, if I use the number, instead of the name displaying in the listbox, the number displays. Is there a way to display the name in the listbox instead of the number? Once I have assigned the number as the keyString, am I stuck displaying that value only?
I have a hash table in which the key is of type Point and the value is of type PieceOfBoard. PieceOfBoard is derived from PictureBox. How do I serialize this hashtable to save it to a file?Do I need to add anything to the PieceOfBoard class?
View 3 RepliesI want my application to do something special :D.. jks
I just want it to compare assembly version to the file version something like this (btw i also want it if it is the same i want it to enable a button):
Private Sub StartSplash_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
If Assembly Version = File Version Then
[Code].....
so how do i detect Assembly & File version numbers?
I would like my program to overwrite its previous version such that users don't have to uninstall the previous version before installing the new one.
I'm guessing it has something to do with setting Publish Version (Major, Minor, Build, Revision), Assembly Version or File Version.
If i have an object that implements an interface (and don't know the exact object) i can call a sub (DoSomething) by going:
vb
Dim iObj = trycast(something, iInterface)
if iObj isnot nothing then
iObj.DoSomething()
end if
How can I do this for a Generic? such as...
vb
Public Class TestClass(of T)
Public sub DoSomething()
....
end class
Is it possible to create a hashtable "pre-populated" with values?[code]...
View 2 RepliesI am using a hashtable to cache incoming UDP messages before my application processes them. After adding pairs to the hashtable, I am experiencing strange behaviour when interogating the collection, such that a containsKey() enquiry returns false, even though the key exists and is visible in the locals window. Spelling etc is correct, manually calling GetHashCode on the key (String) at each point (add() and containsKey()) is returning different values for the same key. To complicate things more, some keys are matched successfully.
View 2 RepliesI currently have a ASP.NET Website and a Windows Service doing some work together.It consists in running some processes either using scheduling or on-demand requests.Basically before i had the windows service i used a Shared Hashtable to register all the on-demand requests and avoid duplicate requests for the same ID. I tought i could use the same hashtable to add the scheduled requests also... but somehow they are being created in separated hashtable's.I think its because the windows service uses a diferent instance of the website.
PS: in the hashtable i save full class objects for future reference so the solution must be able to achieve the same.
I was using the For Each frm as From In Application.OpenForms but it seemed a bit inefficient to loop thru every open form when I already knew what I was looking for. After some googling I found some information about hashtables so I used the following code. This code works as long as another form, say form3, isn't open with the same ID. What I am trying to figure out is, why is the hsh.contains only looking at the key instead of looking at the key/value pair?
Form1
Public hsh as New HashTable
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
[code].....
I am making a small tool that require some calculation. I am using hashtable to store values that I need to calculate. This tool continuously extract data on specific time interval(30 seconds) from webpage and add those data into the hashtable. Now the problem is I need to store the previous extraction data and when new extraction occurs, I need to deduct the previous data from new data.
[Code]...
On first run it shows the result of Data3 = 100 which is currect. But on second run I need to redefine the value of Data2 = Data1 . So I need a result of Data3 = 0 on second run. This may not be the proper way to do this sort of operation. I have also tried using listbox, listview and even textfile to store the Data2 and recall that on second run. But could not make it possible.
This is the last phase of my tool and I am stuck with it.
I have a scenario at work where we have several different tables of data in a format similar to the following:
Table Name: HingeArms
Hght Part #1 Part #2
33 S-HG-088-00 S-HG-089-00
41 S-HG-084-00 S-HG-085-00
[code]....
Where the first column (and possibly more) contains numeric data sorted ascending and represents a range to determine the proper record of data to get (e.g. height <= 33 then Part 1 = S-HG-088-00, height <= 41 then Part 1 = S-HG-084-00, etc.)
I need to lookup and select the nearest match given a specified value. For example, given a height = 34.25, I need to get second record in the set above:
41 S-HG-084-00 S-HG-085-00
These tables are currently stored in a VB.NET Hashtable "cache" of data loaded from a CSV file, where the key for the Hashtable is a composite of the table name and one or more columns from the table that represent the "key" for the record. For example, for the above table, the Hashtable Add for the first record would be:
ht.Add("HingeArms,33","S-HG-088-00,S-HG-089-00")
This seems less than optimal and I have some flexibility to change the structure if necessary (the cache contains data from other tables where direct lookup is possible... these "range" tables just got dumped in because it was "easy"). I was looking for a "Next" method on a Hashtable/Dictionary to give me the closest matching record in the range, but that's obviously not available on the stock classes in VB.NET. what I'm looking for with a Hashtable or in a different structure? It needs to be performant as the lookup will get called often in different sections of code.
This is similar to How to keep the order of elements in hashtable, except for .NET. Is there any Hashtable or Dictionary in .NET that allows you to access it's .Index property for the entry in the order in which it was added to the collection?
View 5 RepliesI try to convert names and values parameters of function into a hashtable. For name of parameter, it's ok, but not for value.
Function test(ByVal param1 As String, ByVal param2 As String) As Hashtable
Dim hash As Hashtable = New Hashtable
Dim stFrame As New StackFrame
[Code]....
There is a property to get default value of parameter (if optional) with param.DefaultValue but how to get current value ?
recently started converting our project from 1.1 to 2.0
It was fine with the following:
Public ghtAllAppMsgs As New Hashtable(300)
Now it is complaining to change to the following is this the right way:
Public ghtAllAppMsgs As New System.Collections.Hashtable(300)
This is under global.vb class file: here are the imports i already had in this file:
Imports Microsoft.Web.UI.WebControls
Imports Microsoft.Web.UI.WebControls.MultiPage
Imports System.Web
[Code]......
