Can I safely modify -I mean: remove and re-add on a different index position- any item that I iterate over using a For Each loop in VB? We are talking about the VB Microsoft.VisualBasic.Collection class.And if yes: Is this by design, or an implementational detail, that I am building upon then?
View 3 RepliesI want to do something different on the last KeyValuePair of the Dictionary I'm iterating on.
For Each item In collection
If ItsTheLastItem
DoX()
[code].....
I've got a panel (pnlExpenses) with several labels and textboxes on it. I want the program to go through the dollar amounts entered in the textboxes and put the subtotal in a class level variable (dcSumOfExpenses). However, when the debugger passes through this Sub, objControl always shows a value of Nothing, and the Count of pnlExpenses.Controls always shows a zero. What is my code missing? The panel was added to a tabpage at design time, and the labels and textboxes were laid on top of the panel. Do I need to do something more to establish the panel's controls as a collection?
Private Sub SumExpenses()
dcSumOfExpenses = 0
Dim objControl As Control
[Code]......
I have a number of idential repeaters, and I need to iterate through all of the items. I currently have:
For Each item In rpt1.Items
.do some stuff
Next[code]....
Is there a simple way to reduce this to a single For Each ... Next loop?
Edit: There are a number of local vars involved in "do some stuff", which is why I can't just pass the item into a function - the call would have to include about 8 ByRef params.
I am just getting back into VB.NET, and I need to ask a question. I am doing a project for a class which requires iterating through 360 items in a scrollable control that will pause every so often. I am thinking I might use either a ListView or GridView, but I am not sure if this is the right way to go or if I need to use a different control all together.
View 3 Repliescurrently 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]......
i have a database that stores clients, categories and sub categories, what i am doing is creating a form that programatically creates tab pages on a tab control for each category and a checked list box with each sub category as an item. so that when the form is displayed it only shows categories and sub categories relevent to the client.
Dim tabpage as Integer = 0
ab.Open("select distinct category from etc etc", connectionstring)
While Not ab.EOF
TabControl1.TabPages.Add(ab.Fields("category").Value)
[Code].....
SELECT ContactID, FirstName, LastName, Male, Female, Email, Address
FROM Contact
WHERE (FirstName LIKE @FirstName + '%')
The above query works and returns values on first names that begin with whatever item I type in a text box.
How can I modify that code to search for items containing specified characters instead of just searching for items that begin with the specified characters. I would still need to use a wildcard because it is a search field. see below for an example
For example can I query the FirstName column to display people who's name contain the letters "an" in that order a before n but anywhere within the word e.g.
- Anna
- Jane
- Samantha
Aren't arrays of object enumerable?Look for the comments in the code
Public Class AddressCollection
Inherits System.Collections.ObjectModel.Collection(Of AddressType)
Public Sub New()
End Sub
[Code]...
I have a simple subroutine that loads a list from a database. I would like to be able to use the same code to load a ListBox and a ComboBox by defining the list type as the common abstract base class ListControl, and see no reason why I can't - except that VB.NET doesn't expose/implement/whatever the Items collection in ListControl. I note with frustration that this is not the case in ASP.NET. At moment my code is ugly because I have to check what type of list control I have passed in, in order to cast it to a type that has an Items collection. (My code may be ugly for numerous other reasons too, but it is beautiful to me). Is there a way to rewrite the code to avoid having to go through the testing and casting nonsense? (I've stripped it down somewhat so that all that remains is where the problem lies).
Sub loadList(ByVal db As SqlDatabase, ByVal strCommandText As String, lstHost As ListControl, Optional bClearList As Boolean = True, Optional bIsListBox As Boolean = True)
If bClearList Then
[code]....
i am trying to sort the items in a collection(of T), by the start date. but i do not know how to do it. i do know that we have to implement list properties.
View 2 RepliesI have a class that represents some business object, such as this:
Public Class MyObject
Inherits SomeBaseObject ' Implements INotifyPropertyChanged and IDataErrorInfo
Private mMyVariable as Integer
Public Property MyVariable as Integer
[code]....
SomeBaseObject implements both INotifyPropertyChanged and IDataErrorInfo, such that a Validate method will populate the appropriate IDataErrorInfo fields when setting the property values.I also have a collection that supports change events, which I eventually bind to a WPF DataGrid.
Public Class MyCollection
Inherits ObservableCollection(Of MyObject)
End Class
Part 1: Let's say that I have a business rule which says that no two items in my collection may have the same value for MyVariable. How do I set up my events (or implement additional interfaces somewhere) to perform this cross-item validation whenever the property value changes on any item in the collection?
Part 2: Suppose I have a list of integers such that whenever I add a new MyObject item to an instance of MyCollection or change the MyVariable property on any item already in the collection, the value of the MyVariable property must exist in this list of integers?
I often have a class defined and I also define another class that is simply a collection of the other class. To do this I found it easiest just to define the other class as Inherits List(Of Type). The reason I define a collection class is to add extra functionality to the collection. Take the following code for example.
Class Car
Property Name As String
Property Year As Short
[Code]....
how can I define my own collection so that I can reference it by index or name like that. Right now I can only reference it by index.
removal of items in a collection or list using the " For Each " statement to iterate through.This code works:
For Each item As ListViewItem In ListView1.SelectedItems
ListView1.Items.Remove(item)
Next
This code does not:
For Each itemChecked As Object In CheckedListBox1.CheckedItems
CheckedListBox1.Items.Remove(itemChecked)
Next
I have been reading on this for hours today to find out why the first code block works, but the second does not.What I've learned is the "For Each" statement implements the IEnumerable interface. I have seen these terms used many times and scratched my head when it didn't make scense, then just moved along, something to strain my brain about later.Today was later...So since the IEnumerable interface is used, the .GetEnumerator method of the IEnumerable interface is called upon at the beginning of the "For Each" block, this evaluates the collection or list as in: For Each item As ListViewItem In myCollection This is done at the beginning of the iteration through the myCollection, so if the myCollection is altered as in:
For Each itemChecked As Object In myCollection
CheckedListBox1.Items.Remove(itemChecked)
Next
The altering of the list returns the error:List that this enumerator is bound to has been modified. An enumerator can only be used if the list does not change.
[code].....
I am trying to add the file information of the contents of a folder to a collection. Although I am getting the collection to hold the correct number of items that the folder contains, all of the collection's items are the details of the last file in the folder.
I'm trying to use a loop to go through each item contained in the folder and then adding the item details to a collection with the following line
nCounter += 1
collFileDetails.Add(NameOfItem, nCounter)
Next NameOfItem
CAUTION: Noob using Win32 API ahead
I want to display a list of open windows on my computer in a rich text box. So, I'm trying to store the names of all windows in myString, and then set RichTextBox1.Text = myString.
Here's the code
Imports System
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
[Code].....
I am trying to work out a way to group a collection of items like an enum so that I can access them through code else where in my program. i.e I have list of items and sub items
[Code]...
I am trying to work out a way to group a collection of items like an enum so that I can access them through code else where in my program.
i.e I have list of items and sub items
CODE:
I would then like to be able to access then like: G1Level1.Leve2.Leve3
Would anyone be able to advise if this is possible or achievable.
I've done a little bit of LINQ but I almost exclusively return some elements from a collection based on some criteria. Now I'm trying to do something similar; let's say I have 50 winForm Controls in a collection - I want to set the .Visible property = True based on the controls name.
How would I do that? Below is my failed attempt.
myControls.AsEnumerable.Select( Function (myControl as Control) ( myControl.Visible = (myControl.Name <> "Hidden")) )
It compiles and even executes but does nothing.
I have a ComboBox control with some items added to the items collection in design mode. What I want is when an item is picked from the ComboBox a different value is actually used in the code, instead of what is displayed. I am aware of the DisplayMember & ValueMember properties, but I'm not sure if that is what I need to use. All the examples I found were for bound data.
View 3 RepliesI have a problem getting the collection of items in the ItemMouseHover event. I want to get the collection of all the items and subitems when the Mouse Hovers in the ListView. I have the property of Full Row select in the ListView.
View 4 Repliesi have a problem getting the collection of items in the ItemMouseHover event. I want to get the collection of all the items and subitems when the Mouse Hovers in the ListView. I have the property of Full Row select in the ListView.
View 2 RepliesHow to create collection class and add list of items to collection class that stores list of items?
View 3 RepliesI am trying to refresh my combobox when an item is selected and added the highlighted code as shown below; [code]Items collection cannot be modified when the DataSource property is set.
View 3 RepliesI have a string array called m_DirFileList and a collection called myFileCollection. I'm trying to loop through the items in the collection and store each one in the string array. It's not working though.
[code]...
I have a string array called m_DirFileList and a collection called myFileCollection. I'm trying to loop through the items in the collection and store each one in the string arrayIt's not working though. This is what I'm trying to do:
Dim myFileCollection As Collection = clsFTPClientClass.GetFileList(fileFilter, True)
intItems = clsFTPClientClass.GetFileList(fileFilter, True).Count()
[code].....
Is it possible to use LINQ to query the items collection of a ComboBox & get the index of the item that matches what I'm looking for?
View 4 RepliesI often use a for/next loop to cycle through a collection to find a particular member of that collection based on some criteria. This works fine in every case except one: when I want to then erase the very member of the collection I just found. For example, if I wanted to give the heave-ho to every obect in a collection class that has a member veriable Color equal to Red:
[Code]...
The problem is once the collection class member is erased it makes to loop invalid because taking out the member reduces the total count of the collection in the middle of the loop. Eventually I get a "Index is out of range" error.This circumstance has bothered me every so often; I bet more experienced programmers have a different type of loop system that works better than this when you want to erase a collection member.
I have a combobobox on my form, and I use the following code to populate the data from SQL Server:
cbname.DataSource = DSAssetName.Tables(0)
cbname.DisplayMember = "IDWLNAME"
cbname.ValueMember = "FIDWID"
[code].....
I can't seem to find any answers that work. Here's the setup:
Info class: Public Class ProductStageInfo
[Code]...
maybe I just don't understand the whole collection/index/thing. All the examples I've found are regarding single dimension collections - 'how to find name within this collection', and the responses use strings to search through them, but somehow the Info class is being treated differently, and I'm not sure how to translate this..