Fast Count Of Same Object Within List?
Mar 28, 2012
I have an operation that will be performed MANY times and so I need it to be as fast as possible, thus I think keeping validations to a minimum is important here.I'm given an image, an offset and a size; and the idea is to take the color that appears the most within the area determined by the size and offset, so far I have this:
Private Shared Function someFunction(image As Bitmap, offset As Point, sampleSize As Size) As Color
Dim pixelsColors As New List(Of Color)
[code]....
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Sep 3, 2009
After reading all the examples for list of T exists and Find and find first, none show how to handle multi-property objects. Below is bare bones example maybe someone could flesh out to show how this should be done.
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim DatePriceList As New List(Of DateAndPrice)
DatePriceList.Add(New DateAndPrice(Date.Parse("1/1/2000"), 10.12))
DatePriceList.Add(New DateAndPrice(Date.Parse("1/2/2000"), 11.12))
[Code]...
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Apr 19, 2012
Dim db As New DataClasses2DataContext
Dim newvet = From n In db.vets Select n.vetid Distinct
(Label1.Text = newvet.Count.ToString)
this is the error message I am getting:Object reference not set to an instance of an object.
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Sep 6, 2011
Limited to using v2.0 of .Net framework (we use VB.net) due to environmental constraints on our servers.I've got an ASP.net webpage which pulls data from a webservice that performs checks on user accounts in active directory. Operators can check multiple accounts at one time using the web interface. The webservice returns a list(of AccountCheck) objects which themselves contain single properties like username, email address, and List(of AccountError) objects which contain multiple properties.[code]What I want to do is using some kind of repeater, create multiple panels or divs which contain labels showing the username, email etc, and a gridview which has the accounterror list bound to it to show all the errors. The users could be checking 2, 5, 7 accounts at once, and is dynamic.
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Jul 20, 2011
I am attempting to read the results from a SQL query into a List(Of) and I can see the List.count while adding items to the List increments, however in another part of my code when I am attempting to read the List the List.Count returns 0. My List is as follows:
[Code]...
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May 19, 2009
I am working in VB.net and have a Class, Foo, that implements an interface, IBar.I have a List of Foo's, but I need to pass a list of IBar's into a function, but I keep getting casting errors, even when I use DirectCast.My code is [code]MainWorks works, but it would be really annoying and inefficient to have to do that everywhere I want to call this function.
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Jun 5, 2012
I have a list(Of transaction) :
[Code]....
How can I transform it to a list(Of transactionShortened) :
[Code]....
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May 29, 2012
Suppose I have a list of Cat.
Public Class Cat
Public Property id As Guid
Public Property name As String
Public Property race As catRace
End Class
How can I quickly transform this List(Of Cat) into a List(Of Guid) using the id property?
I could do :
Dim newList As List(Of Guid)
For each item in catList
newList.Add(item.id)
Next
But I think there must be a way to do this faster (1 LOC). I just can't find how.
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Jun 4, 2010
This is not to manage my own application's GDI leak but another that runs in conjunction. Basically, I want to know if the number of GDI objects for a given process has reached a certain limit. I just need a pointer to the right direction. Should I be doing a "stack walk"?
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Nov 22, 2009
So i have 4 items in a listbox how do i count then up together to show in a label [code]...
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Jan 9, 2010
I'm using this code to count up bytes in list box 5. It works but when the value of bytes is 0 i get this {Width 100, height = 200,) I think the problem is the ToString So does anyone know how to count numbers in the list box?
vb
Dim total As Integer
Dim i As Integer
For i = 0 To ListBox5.Items.Count - 1
[Code].....
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Sep 12, 2011
I have the following code for Customers and their orders. I want to list all the customerID and the corresponding count of orders. How do I achieve it using LINQ? [code]
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Mar 6, 2010
Im trying to count how many items are in a list(of)
I looked it up on google but still cant figure it out.
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Oct 16, 2009
Does link text mean I have to return a concrete implementation? Even though I am using svcutil with the /r that includes my entites(where IMyInterface is defined). I get no errors but it changes all List(of IMyInterface) to list(of Object) and I cannot deserialize it on the client
Error: list(of object) cannot be converted to list(of IMyInterface).
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Mar 18, 2010
We have a serial port which is connected to hundreds of physical devices on the same wire. We have protocols like Modbus and Hart to handle the request and response between the application and devices. The question is related to managing the reference count of the channel. When no device is using the channel, the channel should be closed.
[Code]...
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Apr 17, 2012
I have a the following Class structure. Company > List(of Departments) > List(of Employees) I want to Query a Company to find out if it has a department of the following name and a Employee in that department with the following ID! How could I query this. The way I have the code it expect to return one department so I have it doing
[Code]...
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Feb 1, 2012
In VB.net, when I retrieve a value from a list do I get a copy of that value or a reference to it?
dim blah as someObject
dim listOfBlahs as list(of someObject)
listOfBlah.add(new someObject(1))
[Code]....
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Jun 15, 2011
I need to be able to add elements to a copy of mylist.testlist without modifying the global mylist object. (Which seems to be happening via the below code.)When I am working on x, which should be a totally separate object, mylist is getting modified as well. How can I fix this? I have worked with lists extensively and never seen this behavior before. I have tested and reproduced the problem in .NET 3.5 and .NET 4.0 on Win 7 Pro 32bit.
Source Code:
Public Class Form1
Public mylist As New test
Sub Main()
[code]....
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Jun 2, 2011
I would like to create list of child objects from list of parent object. Like If i have list of bookingroom which has one member room then i would like to create list of room from it.
eg. code:
Dim BookingRoomList As List(Of BookingRoom) = New List(Of BookingRoom)
Dim RoomList As List(Of Room) = New List(Of Room)
BookingRoomList = BookingRooms.FillGrid()
[Code]....
Is there any short cut method instead of iterating over for earch?
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Jun 15, 2012
I am having a problem when setting VB.NET list object to another.I create an instance on ReadLocations and than create an object of ReadLocation where then I loop through ReadLocations and set ReadLocation1 equal to rl. What happens is that if I then go and change ReadLocation1 to something else (assdfhsd) it will also change the ReadLocations index. I am really confused why it would be doing that unless it is "=" sign means referencing instead of actually setting the value. Please help as I am a C# developer but the program I am modifying is in VB.NET.[code]
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May 26, 2011
I have an object (MyObj) that itself will hold a List of other objects of various types and I want to count them as they are added to MyObj.That's the simple explanation, anyways...I have an Interface (MyInterface) that all sub-objects agree to. MyObj has a List(Of MyInterface) property that all the sub-objects are added to. MyInterface will expose a property that lets me figure out what subtype each object is (the sub-objects do not inherit from MyObj at all).
But I want to count these sub-objects as they are added to the list, and I'm trying to find a good way to do it. I don't need to worry about decrementing the count, as I am going to mimic the behavior of String and just create a new instance of MyObj if it ever changes, so all my counts will start from 0. This'll hit the garbage collector a bit, but I think this will allow for simpler (and safer) code. The only sane way I can think of to count objects is a very large structure in MyObj that uses bytes to hold the count (I will never have more than 255 of any given sub-object in the list in MyObj). But, even using bytes, this structure will be about 100-200 bytes big in memory (I have that many sub-objects), and I anticipate having a fair amount of MyObj copies running around, too.
I'll also need a large Select Case to know which count property to increment when a new sub-object is added. This seems to be a bit ugly, though I've used this approach several times already.What I am wondering is, instead of counting each object as it is added to the list, is there some way to query the list and count only the objects of a specific type? I wouldn't need to store this anywhere, since it would be dynamic, like querying a database and asking for a count of a specific column or type of record.I suspect Linq can do this, but Linq is also quite slow. Are there other approaches? Perhaps a predicate of some kind?VB (I am not a C# guy):
From i in MyObj.MyList Group i by i.GetType into g Let c as Int32 = g.Count() And that's it so far. I am still googling, but I am getting way too many C# and SQL references.
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Jul 26, 2011
I need to count the items that meet a criteria in a list(of structure) in .net 2.0. eg
Dim listcars as new list(or car)
Structure car
Dim Name as string
Dim year as integer
End structure
Now i need to count all cars with name toyota etc, how do i do it.
[URL]
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Jul 28, 2010
I have a class having 2 properties (both integers) and storing class into List collection.[code]Here I need return "TRUE". (values in "GroupNo" is not static and not in sort).How can we do that in vb.net?
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Jul 28, 2010
have a class having 2 properties (both integers) and storing class into List collection.
Public Class GroupSelect
Public Property RowNo() As Integer
Get
[Code].....
Here I need return "TRUE". (values in "GroupNo" are not static and not in sort).
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Feb 7, 2012
On to my question.I have a List(of String) that contains multiple items in each index.
A list declared as:
Dim NewStrings As New List(Of String)
May contain the following:
item (0) - (1 MKNO ABC 2.45 STND 3.3)
item (1) - (1 MKGO ABC 1.34 STND 2.5)
item (2) - (1 MKNO ABC 2.45 STND 3.3)
item (3) - (1 MKNO ABC 2.45 STND 3.3)
[Code]...
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Aug 9, 2010
I am learning Linq, so bear with me. I have a class object that holds 4 other class objects with each holding a List(Of T) of the next. Think tiered classes. As these lists as built I need to search all the Group2 for all Group3 to see which Group3.units.count is the largest. "units" being a List(Of T). [code]
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Dec 22, 2010
I have 2 classes
Public Class Shipper
Public Property ShipperID As Long
Public Property CreateDate As DateTime
[Code].....
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Nov 8, 2010
How to know if a List(Of T) contains any control object without using a loop ?This doesn't work
Dim lstObject As New List(Of Object)
lstObject.Add("STRING")
lstObject.Add(2)
[code].....
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Jul 29, 2010
I would like to ask what is the efficiency way the clean and dispose the object collected in the List (Of Object)?
Is that by calling the List.Clear() method will automatic clean all the object collected by it?
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Feb 11, 2011
I am able to populate an object and output everything. How do I remove say the name2 object?
la.Remove(Logins("name2")) doesn't seem to work.
Private Sub btnListArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnListArray.Click
[code]....
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