Pass Collection Of Objects To BackgroundWorker?
Nov 19, 2010
I have an object of type Dictionary(Of Int16, Polygon) and which contains sometimes up to 15 or so Polygons that i am creating bitmap files with the Polygon. This can take like 20 seconds sometimes so i was trying to pass the full Dictionary to background worker as an argument but i get an issue when trying to access each individual Polygon inside of the Dictionary because the Polygons still belong to the UI thread. How can I access the Polygons inside the Dictionary with the backgroundworker?
Dim worker As New BackgroundWorker
AddHandler worker.DoWork, AddressOf MeasurePolygons
AddHandler worker.RunWorkerCompleted, AddressOf WorkerCompleted
worker.RunWorkerAsync(PolygonCollection)
that is how im calling the thread. PolygonCollection is the Dictionary(Of Int16, Polygon) that contains all the polygons that i will be creating a bitmap file out of.
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Oct 17, 2008
Working on a project that tests up to 16 PC boards. The test routines are on a a backgroundworker thread. I want each PC board to perform the test routine on its own thread, so I would need up to 16 backgroundworkers.How do I go by doing this? Do I put 16 Backgroundworkers on the form? I tried to do it programmatically but I can't declare an array of backgroundworkers because withevents variables can't be typed as arrays. I guess I just need a kick in the right direction.
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Feb 7, 2011
Imports SpeechLib
Public Class Form1
Public vox = CreateObject("sapi.spvoice")
[Code].....
How can I pass text2 to vox.speak?
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Feb 9, 2012
I've started working with the backgroundworker class to try and keep the UI responsive while I make some expensive API calls. One of the API classes (details here[msdn.microsoft.com]) has its own event handler which I am using to update a progress bar in a small form that pops up. So I'm looking to use the PublishPackage command in a bgw thread and update a progress bar on the UI thread by using the ProgressHandler method.
[Code]...
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Apr 8, 2012
Passing a value through radio buttons that are in group boxes, this is a project that is upgrading an old program so I already have formulas for figuring out all the rest of the program I am just stuck with how to pass these values to the formulas.[code]...
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Oct 21, 2011
we have 3 classes:Class S, class A, class B / A and B inherits S.A has a property A1 and B has a property B1.we also have a collection of objects that has A and B objects.ex.
Dim c as Collection = new Collection
c.add(new A)
c.add(new B)
Now we want to make a general object that will read from the collection.
ex .
Dim obj as S
how can we cast obj in order to see properties A1 or B1 according to the class;
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Dec 28, 2011
suppose I have a collection of objects of different classes (like controls in a form), and all of their classes have a MyMethod extension method. How do I have the appropriatemethod be called for each object, depending on its type?or example,
For Each ctrl In Me.Controls
'call ctrl real type's MyMethod
Next
[code]....
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Jan 25, 2011
i've researched and written a generic class (all my objects are the same structure) and i'm was just working on the collection using a hash table but i've just read a comment within (url...) in this forum...that we shouldn't use hashtables at all with vs2008.i actually need and object collection that contains other object collections within them.the application i'm trying to write is relatively simple (but i'm new to vb.net)it keeps track of the time for weight lifting training/workouts.a workout consists of 'say' a bench press, military press, curls, dead lift, etc within the "bench" you have 1,2, or 3 sets (how many times you do "the bench", within a set you have 1,2,3 or 4 lifters, each lifter does reps.then it starts over with military press..i guess i could base it on a treeview type structure (with parent child type relationships) but i usually think in terms of collections it appears that a collectionbase has no key and i'd have to keep track of them on my own...
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Nov 16, 2010
I'm trying to figure out the lifetime of the tmpTabPages in the following bit of code. Lets assume the form has an empty TabControl named MyTabControl, that there's a collection of strings called NameCollection.
[Code]...
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May 29, 2009
So I have a collection of Razzies created from a Collection of Bloops. I retrieve this collection using a Linq query. Reference:select-certain-properties-into-another-object for the query.I would like to know if it is possible to run a method on all of the newly created Razzies before returning the collection, or even right after, just without using a for-loop.
I tried ths:
Dim results = From item In bloops _
Select New Razzie() With _
[code].....
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Feb 6, 2010
I would like too generate a number of comboboxes at runtime and then pass them to a Sub, like this:[code]What is the correct syntax to use to pass the comboboxes collection to the Sub?
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Feb 14, 2011
I am using VS2010 (VB) and I am trying to dynamically call a function in another assembly. From my research, I seem to be doing it correctly --- but appearenty not since I get a run time error. {apologies if the code does not come out formated -- the code block helper is not loading for me}Here is the proto type of the function I am calling.
Public Class PrintLabel
Public Function ProcessMany(ByVal listRequests As List(Of Request)) As Windows.Forms.DialogResult
End Function
[code]....
When I step through in debug mode all seems great until I hit the .Invoke() line. It is then I get a paremeter count error exception.
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Nov 24, 2011
I'm implementing a customized Graph algorithm in vb.net, and I'm having the following problem:
Supose the code:
dim col as new collection
dim myC as new system.collections.genericList(of myClass)
dim obj1 as new myClass
dim obj2 as new myClass
[code].....
'In the next statement, the myC2 inside col collection will be decreased to contain 'only obj1, like myC. I supose this is for myC and myC2 contains only a pointer to 'objects obj1 and obj2 as well col contains pointers to myC and myC2 myC.remove(obj2)'The problem is that I have to only copy myC to myC2, like a ByVal argument in a function,'instead a ByRef argument, in order to mantain a copy of objects in myC2 while these 'objects should be removed from myC. How should I do it?
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Jan 29, 2009
Thought I had got this sorted earlier but unfortunately not. A property in a class is a collection of objects.
[Code]...
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Oct 4, 2010
I have a question. I have a class of Cars that I need to display in a simpli-ish string if they will be sold or not base on their number.
[Code]...
I'd like to display a simple string like this:Cars to be sold: 1, 3-5, 7-8, 11, which is based of the .Sell value.Is there some kind of heuristic to create this kind of string in .NET or is it just a bunch of for/each and if/then and redimming of arrays?
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Apr 23, 2012
I am trying to maintain a total for multiple collection objects in a class. When I create a new object, it resets the total to zero, only adding the current value being passed to the function. I have tried to use a static variable, create a second variable to hold the old total while adding the new value. The base class holds the total value, while the sub class creates the new object that holds information. I am passing the new value to a function in the base class adding the new value to the total when each new record is created.
[Code]...
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Mar 6, 2009
i have a sql query that can bring back a large number of rows via a DataReader. Just now I query the DB transform the result set into a List(of ) and data bind the Grid to the List.This can result occasionally in a timeout due to the size of Dataset. I currently have a three teir setup where by the UI is acting on the List of objects in the business layer.
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Feb 28, 2012
I'm having problems doing a sort of a custom collection. The collection is Device Classes which is a collection of Device Class. My sort does not produce an error but the treeview control shows nothing. I am not sure what I am missing. I'm guessing just a simple sort won't work here but I don't know what I'm missing in my code. Here's the code that creates the collection
[Code]...
Simply sorting the treeview will not work because it throws off the display of related info for a given device in listview controls. The collection itself needs to be sorted before the data is added to the treeview.
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Sep 16, 2010
I was just curious as to whether after you have added all of the Parameters to the SQL Command Parameters Collection. Is there a convenient way to iterate or loop through the Parameters and make Assignments to the SQL Command Parameters Values Property?
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Jan 24, 2012
I have a GUI which allows the user to select a report to view/edit. When the user selects a report, it shows the Items in the report. The Item has many properties - most of which are binding properly. One of the properties is Owner, and this is bound to a ComboBoxColumn.
Report
Items
Owner
I have done something very similar to this a few times and had no problems when I set the DataPropertyName, DataSource, ValueMember, and DisplayMember. The only difference is that this time instead of the Item type having an OwnderID it actually has an instance of the Owner object.giving the items bound in the list a self-referencing property that allows them to return themselves for the purposes of setting the ValueMember.However, When I bind it this way:
OwnerColumn.DataPropertyName = "Owner"
OwnerColumn.DataSource = ownersBindingSource1
OwnerColumn.ValueMember = "Self"
OwnerColumn.DisplayMember = "OwnerName"
I get a lot of errors like: Unable to cast object of type 'System.String' to type 'Owner'.
and:
The following exception occurred in the DataGridView:
System.ArgumentException: DataGridViewComboBoxCell value is not valid.To replace this default dialog please handle the DataError event.I was able to get around some of these errors by binding it like this:
OwnerColumn.DataPropertyName = "Owner"
OwnerColumn.DataSource = ownersBindingSource1
and also by making the ToString function on the Owner display the OwnerName property. This seems pretty hacky though - and I think I'm misunderstanding something fundamental as it still does not function properly.
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Nov 11, 2011
I have an error while using a collection that has been stumping me for years.I wrote a class to allow users to write equations in a txt file using RPN (stack based notation).The class runs through a select statement while reading the equation and then ends up with a final number as the answer. I have a collection to place these objects in for easy reference. For whatever reason I get random object reference not set to an instance of an object errors when there is nothing in the program that would remove objects from the collection, kill objects, or change the collection in any way. It is possible for one thread to call the calculate function while another thread calls the CurrentValue property. I'm not sure if this could be causing the error, but once it happens I get an error every time the program enters that code until I run out of memory.
[Code]...
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Jun 10, 2012
I need to Store Objects with Key like:
Key: <Fontname & FontSize> / Object: <Font Object>
Example content:
ArialRegular8 | <Corresponding Font Object>
ImpactItalic10 | <Corresponding Font Object>
TimesRomanRegular12 | <Corresponding Font Object>
These font types come from an external library, the real type is DocumentFont, I prefer not to store just values and recreate the font object later, so I need to store the object, and i want to be able to call Contains() later without looping. like for example Dictionary (of T Key, T Value), is this the best option? Also, to be able to call Contains(), i will have to overload function Contains() using an Interface or this is already built-in in some Collections / Dictionaries when using a String as Key?
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Apr 11, 2011
I created a custom class for a custom object. I instantiate like so[code]...
Now, I have two problems. First, right now this is just overwriting the same object properties, again, and again. I need to somehow dynamically name the object. Then, I need to place these objects in an array so I can iterate through them...
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Mar 19, 2012
I've got a multi-threaded app - that is using a global COLLECTION of objects.I'm starting to think that objects - when copied to objects - are really just reference pointers to the "single object" in memory - as they would be in JAVASCRIPT (too many languages At any rate - this code - when taking the object from the collection to work with is it making a new object to play with or is it working the single object that actually resides in the collection?
[Code]...
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Apr 26, 2011
I'm trying to pass a list of objects to my WCF service, but it doesn't seem I can pass an object list from my console test application. I have an error that states:
Value of type
'System.Collections.Generic.List(Of
ConsoleTestingApp.ServiceReference1.LetterVariables)'
[code]....
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May 20, 2010
I am finding that this may not be possible, but am trying to see if anybody has a solution.
I have four classes, two are core classes and two are those core classes extended[code]...
This fails because es is of type, extSecurity and the base class expects a type of coreSecurity. I've not found anyway to cast this to allow for me to override this base class in C#. In VB it works just fine.
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Feb 26, 2009
We use a custom collection derived from CollectionBase to store our Business objects
[Code]...
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Aug 16, 2010
I'm redesigning an old VB6 application into VB.net and there is one thing I'm not sure on the best way to do. In the VB6 application whenever we created a new instance of a component, we would pass in the user details (user name and the like) so we new who was performing the tasks. However, no that I'm redesigning I've created some nice class designs, but I'm having to add in user details into every class and it just looks wrong.
Is there a VB.net way of doing this so my classes can just have class specific details? Some way so that if my classes need to know who is performing a task, they can get the information themselves, rather than having it passed in whenever the objects are created?
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May 6, 2012
I have created a COM Object via VB .NET and exposed some functions that I wish to call in Excel using VBA. I am currently trying to pass an array of objects as a result to VBA but Excel is complaining the following:
'Function or interface marked as restricted, or the function uses an automation type not supported in Visual Basic.'
I have looked around on the internet and have seen similar issues but not to one I am trying to do.My VB .NET function, which I wish to call in Excel is declared as follows:
Public Function CallArray(ByVal serviceName As String, _
ByVal effectiveDate As String,
ByVal serviceParams() As System.Object,
ByRef ArrayRes() As System.Object) As System.Boolean
VBA is complaining about the System.Objects my question is how the heck are you supposed to pass and return arrays from .NET to VBA. Also the data that will be in the ArrayRes() is mixed type, its not just strings etc, its an array of arrays that can contain strings, integers doubles etc.I chose VB .NET because I assumed it would be possible to map to VBA easier.if System. Object and Arrays in VB .NET is not the way, ie maybe theres another way via collections or lists, then Im open to that. I just need to get this data into VBA.Also I could move over to C# if needs be.
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Oct 15, 2009
What is the best way to pass objects between threads? I would like to create a new thread that creates a new object : Dim myobject as newobject = new newoject Then in my main thread, I would like to use myobject. Ideally I would like to just assign to a global variable but I don't think that is possible. I think I may have to use some form of delegate function (but I think the child thread would need to complete to use a callback). The new thread will not actually end before I need the object reference in the main thread. How should I go about this?
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