Make My Collection Unmodifiable?
Sep 27, 2011
I'm in the process of converting files written in java to vb.net for a window app using vb.net 2005.
In java, they have a way to make a collection "unmodifiable" by calling the collections namespace. This method apparently makes it so the user can't add, remove, clear anything from the collection.[code]...
Returns an unmodifiable view of the specified set. This method allows modules to provide users with "read-only" access to internal sets. Query operations on the returned set "read through" to the specified set, and attempts to modify the returned set, whether direct or via its iterator, result in an UnsupportedOperationException.The returned set will be serializable if the specified set is serializable.
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Feb 8, 2010
I have been researching for a couple of days now and to no avail. Does Anyone know how to make a custom collection that take advantage of the collection editor? I would like to be able to have 3 Color Values, 1 Boolean and 1 String.
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Mar 24, 2009
The situation:I have a collection which contains names and I want to be able to add the names to a combo box, i.e.comboBox.Items.AddRange(theCollection)I get an error that 'collection cannot be converted to a one-dimensional array of object'comboBox.Items.AddRange(theCollection.ToString) doesn't work either.
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Nov 11, 2010
I am wanting to make a collection of form instances.I was wondering if the arrayList is a list of pointers (or references) to items added or if a new instance of an object is placed when using the add method.
i.e. if I had: Public Shared forms as Arraylist = new Arraylist Then if I called forms.add me from an instance of a form would it create a pointer or reference to the instance or generate a whole new one?
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May 12, 2009
I am using VS2008 Pro. I have a simple DVD database built. I'm trying to make a data driven app to store my dvd collection.One of my tables is Actors and is structured as follows.[code]On a form in my app I have a combobox. I'm trying to make it list FirstName LastName ie. Will Smith. I know how to make a query that'll take the LastName and FirstName fields and list it as Actor. I'm having a heck of a time getting it to do that in the combobox as it'll only let me use one field for the display and won't let me use the query I've made.[code]I keep getting some error about schema don't match default query. I know I could simply change the table to only have one field that holds first and last name, but from what I understand that's not proper db practice. I've searched this site and google until I was blue in the face at looking at soulutions that don't match what I'm trying to do.
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Mar 2, 2010
I am trying to make a collection of controls that I can loop through. So I have this code in my form... Dim WizardFrameCollection As New Control.ControlCollection(Nothing)
I then try to add controls to the collection by I get a error "Object reference not set to an instance of an object." WizardFrameCollection.Add(Me.GroupBox1) I am not sure why I am getting this error. Groupbox1 is a groupbox that is on the form.
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Nov 25, 2009
How can I make a comboxbox list the first item in the collection by default in other words i have a collection list
1
2
3
4
5
When program loads I want combobox to load 1
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Jun 30, 2010
Okay I've been wondering about this for a while now, but whenever you assign variable values to objects they tend to just become references to the original object
For example:
Dim copiedCollection As ListBox.ObjectCollection = ListBox1.Items
For Each L As String In copiedCollection
If L = "Goodbye" Then ListBox1.Items.Remove(L)
Next
As soon as it encounters the string "Goodbye" and removes the item from the listbox, the program will throw an error saying the the collection (copiedCollection) has been modified. How can I make copiedCollection a true copy (not a reference) to the Listbox1.Items collection?
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Jan 15, 2010
Is it good practice to store sub-collections of item X inside a parent collection of item X for caching 'filter-queries' which are performed on the parent collection? (They won't be used together (as in color AND type).) Or is it also ok to just Loop over the collection and return the correct entities in a temporary collection?
[Code]...
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Sep 7, 2011
I have the following classes:
Product, Service and OrderItem
Product and Service must inherit OrderItem. So basically I want to store OrderItem object in my shopping cart and these object are store in a list.
Public MustInherit Class OrderItem
Private m_enuItemType As TypeOfItem = TypeOfItem.None
Private m_strUserID As Integer[code].....
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Jul 25, 2011
I'm trying to support Basic.NET on my framework so I'm trying to convert C# 4 code to Basic.NET 10. Microsoft is committed to "co-evolve" these two but I'm having a problem with collection initialization... I found that I can initialize a collection much like in C#:
[Code]...
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Apr 15, 2009
I've got the following ADO.NET Entity Framework Entity Data Model:I want to find all the Policyholders with both a Service of a given Id and also a Keyword of a given Status.
This LINQ Does Not Work:
Dim ServicesId As Integer = ...
Dim KeywordStatus As Integer = ...
Dim FoundPolicyholders = From p As Policyholder In db.PolicyholderSet.Include("Keywords").Include("Services") _
Where p.Services.Id = ServicesId _
And p.Keywords.Status = KeywordStatus _
Select p
The Where clause cannot search the p.Services and p.Keywords EntityCollections in that way.
[Code]...
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Apr 6, 2012
currently in my application I have a Global Collection that is a Collection of Collections.Currently I am trying to add items/ elements to one of the child collections of the Global Collection but I am unable to use the collections methods of the child.When I assign a variable to the child collection and return the collection it is just an object with the collection inside.
Ex:
Dim GlobalCollection as New Collection
Dim ChildCollection1 as New Collection
Dim tempCurrentCollection[code]......
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Dec 17, 2009
I've been working with a CMS called InsiteCreations 2008. I'm running into an error I just can't wrap my head around. I would even be willing to compensate anyone a small amount over paypal, for a solution. The error is rare in occurance, and appears when clicking about 3-4% of links to other pages within our CMS.The full code page is quite large, but there seems to be only one function associated with the error. The error also only appears when not logged into the CMS. If logged into the CMS, clicking the link simply displays the page as normal. I have already checked permissions on the page from the CMS admin console, and it is public.
The error message is as follows:
Server Error in '/' Application.Collection index must be in the range 1 to the size of the collection.
Description:
An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
[code]....
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Apr 15, 2011
search the collection of a collection in my LINQ Where clause?
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Apr 14, 2011
Take the following scenario:
Public Class Store
Public Overridable Property Areas As List(Of Area)
End Class
Public Class Area
[code]....
What's the quickest way to get a total count of shelves for a store? I.e. for a store I get the total count of areas by using Areas.Count Or will I need to loop through each area and tally the count of shelves?
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Mar 25, 2011
I have an ASP.NET app with lots of textboxes all over the page that need updating at various points through program execution. These textboxes actually belong to a certain class, so for easy updating I thought I could create a Dictionary(Of string, object) and add the control.ID and the control to it and then for updating do something like this:
[Code]...
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Jun 26, 2012
I need to convert a VB Collection to a modern one, like Dictionary or Hashtable. For my approach, I need the Collection's KEYS. Googling tells me that it's impossible. Re-writing the entire application using new collections is not an option as the application is really old and large (converted from VB6 to VB.Net).Using the old Collection also is not good - as there are new components in development.Converting a - for example - Hashtable to Collection works:
using VBCollection = Microsoft.VisualBasic.Collection;
public static VBCollection ToVBCollection(this Hashtable table)
{
[code]....
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Aug 12, 2009
I have a collection of lines and as i loop through through the collection, i need to see if it aleady contains a certain line; however, the contains method wants a string and i have stored lines, so how can i use this method to see if my line is already in the collection so i don't place it in there twice?
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Aug 4, 2011
Is it possible to print to a collection(), then prompt to print the collection?
[Code]....
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May 31, 2012
Why is the Collection in the Microsoft.VisualBasic library? Why is it not in a more general location. Is there a reason Microsoft "hid" it from C#?
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May 29, 2012
What I'm trying to do is get the value from a collection. While debugging I can see that the value from my collection is exactly what I want.
This line contains the value I want: Groups.Add(dn.Substring((equalsIndex + 1), (commaIndex - equalsIndex) - 1))
All I'm trying to do is export all the values to a textbox, and I can't seem to figure out how I can use it.
Below is just some more of the code I'm working with.
The property of the line is {Microsoft.VisualBasic.Collection.KeyValuePair} the key has no data, but the value has what I need.
Dim equalsIndex As String
Dim commaIndex As String
For i As Integer = 0 To propCount - 1
[Code].....
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Oct 21, 2010
I am populating an XML structure (using VB.NET) to pass to a web service. Here is how one piece of the structure is filled, and the rest of the structure is filled in a similar manner:
Private Shared Function GetSpecialties(ByVal specialties As System.Data.Linq.EntitySet(Of Provider.provider_specialty)) As XElement
Return _
New XElement( _
[code]....
Some pieces of the structure can contain up to 30 elements. Each record takes about .1 seconds to create, and it needs to create about 35,000 records, so the whole process takes about an hour.Is there a quicker way to fill an XML structure like this?
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Sep 18, 2011
Recently I found that I'm not able to instantiate a structure for an array:
Dim mObjectLists() As New objectLayout
Ok, fair but It's an easy way to store a bunch of data in an array instead define a class. And after that I tried to define this:
Dim mObjectLists() As Collection
And add structures to the collection. But it says you should instantiate the reference object first. I searched about creating own Collection based on the base collection class but I think It's wasting time to write a code with class inheritance instead the first sample.
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Jul 19, 2010
how can I place all timers on a form into a collection
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Jul 7, 2010
[This is a simplified example] I have a collection ("myCollection") in which exists three entries: ("hello", "goodbye", "welcome"). I want to iterate through the collection and if in the collection there is the entry "welcome" I want to take one action, if that entry doesn't exist I want to do something else. Like this (pseudo):
[Code]...
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Aug 16, 2009
The following code creates a Collection where every Item is assigned a value equal to the last item added. At the end of adding for example seven items all the entries are identical to the last one added, although each has the correct key
The parameter passed to the function - aCOA() - is a comma delimited string of three strings.
The code is as follows
Public Function myCOA(ByVal aCOA() As String)
Dim thisCOA As New Collection
Dim keyCOA As String
[Code]....
Is this a bug in the code or in the Collection Class. I have traced the operation of the code and all seems OK until the second entry is added at which time the first entry Item get the same value as the second entry Item and so on.
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Apr 22, 2010
I am writing a program that needs to read a set of records that describe the register map of a device I need to communicate with. Each record will have a handfull of fields that describe the properties of each register. I don't really need to edit or modify the data in my VB or C# program, though I would like to be able to display the data on a grid. I would like to store the data in a CSV file, or perhaps an XML file. I need to enable users to edit the data off-line, preferably in excel.
I am considering using a DataTable or a Collection of "Register" objects (which I would define). I prototyped a DataTable, and found I can read/write XML easily using the built in methods and I can easily bind to a DataGridView. I was not able to find a way to retreive info on a single register without using a query that returns a collection of rows, even though I defined a unique primaty key column. The syntax to get a value from a column is also complex, though I could be missing something on both counts.
[Code]....
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May 25, 2009
I have worked some with classes and collections in the past but seek some direction before I start on this project as to the best method to use.I will be reading 20,000 or so lines from a text file. partno, desc and loc Each will contain 3 elements to be collected and stored temporarily.There are 2 results that I desire that relates to selling of products
First Result: Sorted list of most used partno, desc
2,234 partno (most sold)
1,345 partno (2nd most popular)
etc.
2nd Result: Sorted list by specific loc., partno, desc
loc. 45 - 234ea partno, desc
loc. 45 - 143ea partno, desc
Maybe end up with the top 500 selling products in the list. This data will then be added to a dataviewgrid for printing and then deleted.So, to temporary store and sort should I use some type of collection or classes? I know how to fight my way to either but which would be the best method?
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Oct 6, 2009
I have built a class to store profile information and there is another class that inherits System.Collections.CollectionBase that actually holds the data objects. Now the issue is when the page is refreshed the entire class is wiped off the map.
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