Compare Ways To Instantiate A DataTable?
Feb 17, 2012Presuming "instantiate" is the appropriate terminology, may I get some insight as to which of these are better, more efficient,[code]...
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Overriding CompareTo When There Are Multiple Ways To Compare Two Objects Of The Same Type?
Jan 12, 2011What's a sound approach to override the CompareTo() method in a custom class with multiple approaches to comparing the data contained in the class? I'm attempting to implement IComparable(Of T) just so I have a few of the baseline interfaces implemented. Not planning on doing any sorting yet, but this will save me down the road if I need to.
Reading MSDN states mostly that we have to return 0 if the objects are equal, -1 if obj1 is less than obj2, or 1 is obj1 is greater than obj2. But that's rather simplistic.
Consider an IPv4 address (which is what I'm implementing in my class). There's two main numbers to consider -- the IP address itself, and the CIDR. An IPv4 address by itself is assumed to have a CIDR of /32, so in that case, in a CompareTo method, I can just compare the addresses directly to determine if one is greater or less than the other. But when the CIDR's are different, then things get tricky.
Assume obj1 is 10.0.0.0/8 and obj2 is 192.168.75.0/24. I could compare these two addresses a number of ways. I could just ignore the CIDR, and still regard as obj2 as being greater than obj1. I could compare them based on their CIDR, which would be comparing the size of the network (and a /8 will trump a /24 quite easily). I could compare them on both their numerical address AND their CIDR, on the off chance obj2 was actually an address inside the network defined by obj1.
What's the kind of approach used to handle situations like this? Can I define two CompareTo methods, overloaded, such that one would evaluate one address relative to another address, and the second would evaluate the size of the overall network? How would the .NET framework be told which one to use depending on how one might want to sort an array? Or do some other function that relies on CompareTo()?
Compare Two DataTable?
May 25, 2010i want to compare the two data table columns and find duplicates
for example
dataTable1
autoid ponbr polinenbr quantity
[code].....
Datatable Compare Rows?
Apr 17, 2009I have a datatable object, which is populated from a webservice.Apparently, the web service just throws everything (data) back to me. The data which gets in my datatable looks like this:
Dept Code Value
Science ABC 5
Science ABC 6
[code].....
Compare Two Datatable And Delete Some Rows By Linq?
Nov 18, 2010there is two datatable at some datasetsone of them is tbl1 and fileds is (pcode,points) other table is tbl2 and fields is (pcode,stoped)"pcode" is equal at two tables
View 6 RepliesCompare DataTable Column Rows To TextBox.Text?
Apr 27, 2012I have a Data Table Column with multiple Rows of data. I need to search all lines of TextBox1.Text for any data that is identical to any row in the specified data column ("MCaddRG"). Also any identical findings need to be made into a new text file or a new form with a text box.[code]...
*Also if it is possible I would really like to have a check box list that contains the data from the "Device" columns so I could check the "Device" and then it search the TextBox.Text for the checked "Device's" "MCaddRG"
Compare Date - Compare Textbox1 And Textbox2 Text
Mar 3, 2010I have two textbox in my application.
Textbox1.Text="19-Jan-2010"
Textbox2.Text="Jan 2010"
May I know how can I compare that Textbox1 and Textbox2 text is within same month and same year?
.net - C#: Different Ways To Run Code Asynchronously?
Feb 14, 2011I have this code List<string> myList = new List<string>();
myList.AddRange(new MyClass1().Load());
myList.AddRange(new MyClass2().Load());
myList.AddRange(new MyClass3().Load());
myList.DoSomethingWithValues();
What's the best way of running an arbitrary number of Load() methods asynchronously and then ensuring DoSomethingWithValues() runs when all asynchronous threads have completed (of course without incrementing a variable every time a callback happens and waiting for == 3)
Chat System With One Or Two Ways?
Jan 15, 2010I'm trying con build a simple chat client/software (whole in on executable) wich start listen from the start on the port 5900 and when a client connect to that port the chat is established.
The problem is that only the client can chat to the server, the server cannot answer the client because the connection is working in one way.The i've tried to connect from "server" to the client when it establishes a connection but the system crash warning me that the port is already on use.
[Code]...
Delete A File In Many Different Ways?
Nov 14, 2011What is the difference between these ways to delete a file.Is one of the methods better than the other?Are there other ways to delete a file (. Net 4)
System.IO.File.Delete(path
to file)
My.Computer.FileSystem.DeleteFile(path to file)
Different Ways For Playing Audio (MP3)?
Jan 28, 2009I'm new to VB and have over the last week or two been looking at the different ways to play audio (mp3's). Windows Media Player, Microsoft Multimedia Control, Bass.dll, SndPlaySound, MCI SendString and DirectX (including audiovideoplayback, direct3d and directsound.) I originally decided to use windows mediaplayer, mainly because it seemed the logical choice but quickly found out I couldn't get it to work properly.
So I installed the Directx SDK but now I'm completely overwhelmed about what to use and why. I need to be able run the compiled code on a win 2k box, play an mp3 from start to finish then load and play another mp3 from start to finish and so on. Whats the difference between the varied choices and which would be the best for me to use?
Different Ways To Create Object
Jun 13, 2011I want to know by how many different ways I can create an object. The most common usage I am aware about is:
Dim obj as ClassA = new ClassA().
Different Ways To Declare Variables?
Aug 20, 2009I'm new to VB.NET programming.What I'm confused about is the different ways one can declare a variable.Would someone please explain the difference between the two declarations below? [code]
View 2 RepliesDifferent Ways To Play Audio?
Dec 10, 2009I'm new to VB and have over the last week or two been looking at the different ways to play audio (mp3's). Windows Media Player, Microsoft Multimedia Control, Bass.dll, SndPlaySound, MCI SendString and DirectX (including audiovideoplayback, direct3d and directsound.)I origninally decided to use windows mediaplayer, mainly because it seemed the logical choice but quickly found out i couldn't get it to work properly. So i installed the Directx SDK but now i'm completely overwhelmed about what to use and why.
View 3 RepliesDifferent Ways To Sending Emails Using .net?
Jul 14, 2009What are the different ways to send the emails using vb.net?
View 4 RepliesWays To Play Audio?
May 4, 2010I'm looking at creating an mp3 player to keep myself busy. However I'm trying everything I can to avoid using the windows media player COM component. It makes it a little too easyWhile looking around I stumbled upon the DirectX.AudioVideoPlayback namespace and I was wondering if this would be sufficient. Would I be able to create an equalizer and other more advanced things for my application?
View 2 RepliesWays To Play Mp3s
Jun 20, 2012Just found out the hardway that there is no longer support for Direcshow for VB.net and C#. Does anyone know other ways of playing mp3s in VB.net, or even video for that matter?
View 9 RepliesC# - Instantiate The Object To Use It In The Immediate Window?
Dec 13, 2011If I have a console application containing the class
[Code]...
I'm not a VB.NET guy. Am I correct in assuming I need to instantiate my object first? Why does the VB.NET example differ?
How To Instantiate A Class In A Web Site
Sep 28, 2009I have created a WebSite with a folder called Classes. In the folder, there is a class with a Public Shared Function. How do I go about instantiating that class so I can use that function on a web form?
View 5 RepliesInstantiate A New Object From My Class?
Jun 11, 2009I'm trying to decide whether to get a value, call it X, in my class through a read only property or through a function. Normally I'd code it as a property except in this case the GET involves doing a lookup to a sql table. So there's way more overhead than a simple RETURN X. So my question is, when I instantiate a new object from my class, are all the properties calculated at that point, so that the sql lookup will occur too? Or is the property only evaluated when I actually reference it in the calling code.
View 3 RepliesInstantiate And Name Listbox Dynamically?
Jun 5, 2009I want to instantiate and name a listbox based on the value of a textbox. If the listbox already exists by this name (textbox value) I want to add items to the list.
View 14 RepliesInstantiate Local Variable By Value?
Jan 7, 2010I sort of understand why this is happening, but not entirely. I have a base class with a Shared (Static) variable, declared like so:
Public Shared myVar As New MyObject(arg1, arg2)
In a method of a derived class, I set a local variable like so:
Dim myLocalVar As MyObject = myVar
Now when I do something like myLocalVar.Property1 += value, the value in Property1 persists to the next call of that method! I suppose I get why it would be happening; myVar is being set by reference instead of by value, but I've never encountered anything like this before. Is there any way (other than my workaround which is to just create a new object using the property values of myVar) to create myLocalVar by value?
Instantiate Type Of Object With Dim?
Oct 31, 2009i wanted to do something simple that sort of replicate an object:
public function clone(byval realcopy as object) as object return new Control ' something like this works, however i want to return the type of realcopy, which may not be a control end function so i tried this:
public function clone(byval realcopy as object) as object
return new gettype(realcopy.gettype)
end function
Instantiate While Remaining De-coupled?
Jan 24, 2011Just a bit of an issue that we're trying to resolve here. Assuming We're implementing a business model as one dll and a data access layer as another dll. We want them to be de-coupled so we implement an interface for the data-access layer. Great, we could now swap out the data access layer and, as long as the new data access layer fulfils the interface we're good to go, right?
Except we're not. In the business model we need to insanciate the data access layer and, because you can't instanciate an interface, you have to instanciate the actual class. We need to know the name space and the class name.We're going to end up with a line of code somewhere in our business model that looks something like this:-
Dim test as iDataLayer
test = new namespace.DataLayer
Basically, we can declare test as an iDataLayer (the interface) but to instanciate it we need to refer to the actual class (DataLayer). So we haven't really removed the coupling. If we want to swap out the data layer for a different implementation with a possibly different class name or namespace then we need to ammend the code in the business model. We're trying to avoid that.
So far the best we can come up with is to use the activate instance method instead of the New keyword (Late Binding). Because that takes a string we could hold the namespace and classname in a config file or similar, so swapping out one component wouldn't invalidate the others, you'd just need to update the config. That's just our home-spun solution though and I can't help feeling there are betters ways out there.
Possible To Instantiate And Invoke Delegate By Name?
Mar 5, 2009I'm trying to figure out if it is possible to instantiate and invoke a delegate by name, rather than explicitly. I think the code below explains it fairly well. I want to accept a function name and then instantiate the delegate based on that. In the example I use a select case, but I want to eliminate that and just use the methodName argument itself.
Private Delegate Sub myDelegate()
Private Sub myDelegate_Implementation1()
'Some code
End Sub
Private Sub myDelegate_Implementation2()
[Code] .....
Possible To Instantiate New Instance Of Interface?
Jun 5, 2009I have defined an interface named IEmployee (ID, FirstName and Surname properties) but I have not yet implemented that interface in any class. What I want to do is something like:
Dim User as New IEmployee
User.ID = 1
User.FirstName = ""
User.Surname = ""
Call SomeFunction (User)
The VB.NET complier does not seem to like this.
Reference Versus Instantiate?
Aug 25, 2011what actually goes on inside the pc when I reference an object vs when I instantiate it.
Like this
Guys joe; (reference)
Joe = new Guys; (instantiate).So what goes on inside the computer for each line above.
Better Ways For Reading And Writing To .txt Files?
Jun 29, 2006I am trying to create a bunch of records, there will be a limited number of "Codes", about 50. Each "Code" is associated with a name from a textbox, I was trying to have it save each one when you click a button, to a .txt file.So, from the start the record will be blank, the person will go through the form, choose a number from a numerical up and down box, pick a name associated with it (both of these are mandatory and not implied). When they click the button, it will save the contents I talked about into a .txt file, say the number is #2, and the name is "Bob", the next time they try to change that value for #2, it will overwrite "Bob".
View 6 RepliesDifferent Ways To Test DBNull From Dataset
Oct 6, 2009Im using VB in VS 2005.I have found several methods of testing if a value from a dataset is null. Are there differences between these two ways of doing it:
[code...]
Is one faster than the other? From some searching online, there seems to be debate about the best way to handle null values.
How To Setup MyClass To Work Both Ways
May 7, 2010I'm using VS 2010 so I have auto-implemented properties.I have a class and I want to access the properties by a string.[code]But, I also want to be able to access the variables something like this way.[code]How can I setup MyClass to work both ways?
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