Adding A Bunch Of Values To A List(Of T) Collection At Once?
Mar 12, 2010
I am creating an instance of a Generic List collection and I am surprised to find that I can't add more than one value to it at a time. I was thinking there was going to be something like what you can do with arrays, where you can add a group of values to it at creation. I saw the AddRange method, but that seems to add another collection to the end of this collection, which is not what I want. So my code is:
vb
Dim MyList as New List(Of String)
MyList.Add("John")
MyList.Add("Bob")
[Code].....
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Jun 7, 2011
I am trying to create a simple Word doc that when the user presses the button it takes the information in the boxes and tosses it into a template style paragraph. But my issue is that I have two combo list boxes as seen in the picture. I want to have two values in the drop down list as seen in the labels next to them but for the life of me I can't figure out how to do this in Word 2007. In Visual Studio this is much easier but I am work and need to snap this out for the folks at work. Is there an option that I can choose in the properties where I type in the values for each drop down or do I have to add them in at run time?
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Sep 27, 2011
I'm trying to populate class properties where one property is a list collection. I get a NullReferenceException when trying to add to the list collection. The code (litlle bit simplified) is here:
Public Class Portfolio
Property Name As String
Property Assets As List(Of Asset)
Public Sub Populate(ByVal data As DataTable)
For Each row As DataRow In data.Rows
[Code] .....
I have a nested class "Asset" inside the class "Portfolio". Everything goes ok until the line
Me.Assets.Add(asset)
Which gives me the NullReferenceException error.
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Mar 10, 2012
I've been building a simple card game in VB using VB 2010 express. I've built a simple Card class, as follows:
Public Class Card
Public Property Number As Integer
Public Property Suit As String
Public Property Image As String
End Class
I setup a base deck to create the unique, individual cards, which will then be used in multi-deck games. I have a game table form where the cards will be displayed. I declared this base deck inside the game table form and built it during the form's load event:
Public Class Main_Table
Public baseDeck As List(Of Card) = New List(Of Card)
Private Sub Main_Table_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim myCard As Card = New Card()
[Code] .....
Everything runs fine up until the end of Main_Table_Load. I've inspected the baseDeck values and they are correct. But when the Build_Deck_Click sub is invoked, the baseDeck collection's values become all the same, specifically it becomes composed of copies of the last card I built. I've stepped through the code and expanded baseDeck to confirm that all Cards become the same. I've tried moving the Public baseDeck As List(Of Card) = New List(Of Card) to a different module, with the same results. Since I will be using the baseDeck list through the app, I can't declare it privately inside the form_load event, as I'd have to re-create it every time I need to use it.
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Oct 28, 2011
I would like to store references to a bunch of structs in a collection. The general scaffolding looks like this:
Structure myStructType
Dim prop1 as String
Dim prop2 as int
End Structure
[Code]....
now this doesn't work, because it's referencing the same memory. What I would really want is the 'pass reference by value' behaviour that is also used for reference types, so that I can easily keep producing more of them.
Is there any way to fix this other than to make the structs into classes? Is this actually a proper way to use structs, or do I have it all wrong?
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Dec 18, 2010
Speed is critical in my application. As of now, I'm using an ArrayList to store a list of Strings and I use BinarySearch functionality of ArrayLists to search for an item. Would I be able to do this faster using String Collection and a for loop?
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Mar 29, 2011
I am trying to add a value to an array by converting it to a list [code]...
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Dec 10, 2009
I have 1 list view box that has 2 colums. one for the product and the other for the cost. My question is how would I allow a user to add values to that?
My basic layout is, There is a settings window that has about 10 rows of text boxes and 2 colums. I want the user to be able to type in multiple items and prices then hit save and exit for the products to save to a my.setting
and then use this my.setting to bring the users lists up in a list view box.
Since the product and the list price are paired I also need to keep them together in there pairs.
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Jul 15, 2010
I have a problem with a generic list, which consists of intances of a class i created. I am just amazed, each time I add a new object to the list, it overwrites the previous entries. Here is a code sample, i just can't beleive it. I am using visual studio 2010:
Dim translations As List(Of TranslatedValue) = New List(Of TranslatedValue)
If Session("ctlTexts") Is Nothing Then
Dim reader As IDataReader = DataAccessFunctions.db.GetDataReader("SELECT [ControlID], [ControlTextEN], [ControlTextDE], [ControlTextBG] FROM [dbo].[tbLanguage]", GetConnectionString)
[code]....
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Mar 13, 2010
When I implement this code, the first time the button is activated, the values are placed in the array, and displyed in the list box. However if the user then selects more days and times to add to the list box, and activates the button again, the previously added entries in the array are erased, and only the new entries are displayed. How can I prevent previous entries from being erased? If the user wants to add values, they need to be added to the existing values.[code]
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Apr 2, 2010
I'm looking for a tutorial on how to Adding a list(of Class) or Collection as another Class's Property.What I am after is something like the Columns Collection for the DatagridView control.I would like to add Items in the graphics screen. Where the item list is displayed in the left panel and the selected Item properties are displayed in the right panel.
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Jun 7, 2012
I'm trying to store a bunch of integers into a list. I need to be able to find a integer in the list, and change it somehow. I've tried an array, but it wont let me change the values?
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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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Jun 18, 2009
I need to make basically a bunch of 2d arrays, that I can access the independant values easily. Like multiple properties As an example:
[code]...
Because later I have to access Value1 in a manner that spells out each independantly. I have used some basic Structures to define 1 property and does something with it. But not 2 properties, and I am out of my norm on creating a Class to do something like this.
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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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Oct 17, 2009
Reflection on Objects is quite simple, not so seems to be on static things, like modules ( module1.vb ecc... )My question is HOW to gather information from VB Modules and then use them to copy values from a bunch of Public Variables on Module1 to same-named Variables on Module2.I've tried a thing like this by now :
ListBox1.Items.Clear()
Dim A As System.Reflection.Assembly = System.Reflection.Assembly.GetExecutingAssembly
[code]....
With GetMembers( NO FLAGS ) I manage to get list of members, but If I try to get only my-declared-memebrs ( with any combination of flags ) I get none.Finally, what i'd like to achieve is this :
1. Read all Public Variables form Module1.
2. For each Public Variable in Module1, put same value in Variable on Module2 which has same name and type.
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Dec 22, 2010
I was wondering the best method or code to Sum\total a bunch of cell values of an unbound column in a datagrid to a textbox string. this request is 100% genuine...im not some student trying to get you guys to finish my project, this is purely for educational and personal information for myself. im new to vb.net.
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Jan 4, 2011
i have retrived this datatable from datasource and i want to add a more colum 'category'basedon the each value of each Role, like if role column has the value '90 daya client' then in the same row it should have a value 'DC' in the category column.n make a temporatry dt1 table but to add related values.
S.No First Name Last Name Role Date
1 Us er1Name User1Name 90 Day Client 11/01/2011
2 User1NameAtt1 User1NameAtt1 90 Day Client 11/01/2011
[code].....
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Apr 11, 2010
I know you are going to lough about this , but I guess I deserve it ...I am sure I am doing something wrong , but I can't find it out ...I have created a collection , lets sayMyCollectionI have also created a class , lets call itMyClass
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Jun 25, 2011
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
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Jun 2, 2011
I'm trying to make a collection class for buttons to address them as a whole, only I want to design the buttons at design time, and not add/set their properties programatically at runtime. Each button has its own image, so it doesn't seem right to add a bunch of lines of code which assign the properties when they're always going to be the same thing.Is it possible to create the controls at design time and then add them to an array at runtime? I did this, iterating through the buttons on the form and adding each of them to the class below.The problem is that once they're added they seem to be a different instance because changing their positions has no effect on the design-buttons on the form. Essentially i wanted the collection to be a reference to the items belonging to the form.Is that possible or should I be doing this a different way?[code]
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May 7, 2010
I have run into this problem a number of times, and I am not sure what I might be doing wrong - or if this is just a bug, or not going to work.I have a collection that I setup on my own (eg, collection class). I then cycle a Log file that has text entires and I read those, and then parse the entry and attempt to add it to my collection.
But as each entry is added, ALL records just get duplicated - in other words, as I add entry 2, both entrys 1 AND 2 wind up with the same values - as I add 3, all 3 entries get the same value - and this continues no matter how many entries. For example,
if I added 100 entries, I would have 100 duplicates of the last record added.I have stepped through the debugger and watched this occur and just cannot figure out why this is not working as it should. Here is the code...
While
Not objReader.EndOfStream
' Read one full line
[code]....
No matter what I do, my lstSent collection just winds up with EVERY entry being the same as the last entry added.
End
IfFalse'
Add the elements into the collection if its a "Sent" itemElem = objReader.ReadLine
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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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Jan 14, 2011
i have a string = "/a/value1/x/valueforx/b/value2/c/value3"
the keys a, b, and c can be in any order in the string that is coming in and will always be separated by a slash.
What i need to do is to find a, b, c and then add their values to a collection
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Oct 28, 2009
I am trying to extend the functionality of the ToolStripPanel control (which is a panel hosting ToolStrips that can be moved during design-time, as I'm sure you know).One thing I wanted to add was a 'ToolStrips' property, which would be a collection of ToolStrips the user can edit via the collection editor in the designer. So instead of manually placing ToolStrips on the ToolStripPanel via the toolbox, the user can just use the property to add/remove (or even edit) them. This is of course similar to how you add/remove/edit TabPages in a TabControl.So, I came up with this code, which I have used successfully in the past for other controls:
Public Class cToolStripPanel
Inherits ToolStripPanel
Private _ToolStrips As New ToolStripCollection(Me)[CODE]....
The cToolStripPanel control inherits the ToolStripPanel control and adds the ToolStrips property, which is of type ToolStripCollection. That class, in turn, inherits the Collection(Of ToolStrip). In the InsertItem method, I add the 'item' ToolStrip to the cToolStripPanel. Of course I also need to override the RemoveItem / ClearItems methods but that's for another time.I am 100% sure that this code should works, at least for other controls. If you replace ToolStrip with Button (for example), I can add buttons via the property during design-time just fine, exactly the way I want it.But it seems that ToolStrips are special. When I try to Add a toolstrip (via the collection editor Add button), a null reference exception occurs. I've been trying to debug this all day and I've finally come up with a possible candidate for the problem... (I've actually used design-time debugging for the first time ever, which was pretty cool, and which showed me that the InsertItem method is not run!)
I think the problem is that the collection editor cannot create a new instance of the ToolStrip class. I can remember when trying to inherit from the ToolStrip, I was forced to add a constructor, because the ToolStrip "has more than one constructor that can be called with no arguments".Perhaps this is causing my problem? Do I (and if yes, how?) have to somehow control the creation of a new instance of the ToolStrip? Or am I completely off track and that is not what is causing the problem? I'm sure that it's a problem with the ToolStrip class, since I can use the exact same method with other controls just fine. It's only when I change the type to ToolStrip that it starts getting angry at me....
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Mar 17, 2009
Is there a way to to combine line's 1 and 2? I only want to loop through a list of the selected items in this listbox. This works just fine, I just wondered if there was a collection of selected values returned that I could use to avoid having to do it this way.
For Loop1 = 0 To MyListBox.Items.Count - 1
If MyListBox.Items(Loop1).Selected = True Then
...
End
Next
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Jul 9, 2012
Ok, letīs see, iīm kind of new to this so letīs see if you can follow...I have a IEnumerable list of objects:
Dim
objStudentUsers
As
[code].....
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Mar 16, 2012
I was wondering if its possible to bind a datagrid column to a list (Of T) thats stored within an observable collection!
Here's my current code:
Dim _BindWithThis As New List(Of BindWithThis)
Me.DataContext = _BindWithThis
For i = 0 To 3
[Code]....
This currently displays four rows of "(Collection)". Is it possible to step into one of these "Collection" rows and display the data? I know that this is possible to do with a list box by binding with a specific element in the collection:
ListBox1.ItemsSource = _BindWithThis.Item(0).DataValue
I just can't work out how to do this with a datagrid...
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Dec 21, 2011
I can not find the collection on toolTips (I need to do this dynamically across forms).
vb
For Each theToolTip As ToolTip In getControls(theForm)
Next
error :Error 12 Value of type 'System.Windows.Forms.Control' cannot be converted to 'System.Windows.Forms.ToolTip'. C:UsersJeffDocumentsJeffWorkSpace2StudyX.NETModule1.vb 3690 51 study
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Sep 9, 2009
I wanted to know if it's possible to remove a paticular item in my collection and then add it back at a certain location? e.g. say I use RemoveAt and remove the first item in the colleciton; after, I want to add it back at a particular location (index)? Maybe this isn't possible with this type or any other type collection?
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