Adding To List Collection Generates Error?
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.
View 4 Replies
ADVERTISEMENT
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].....
View 1 Replies
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].....
View 18 Replies
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.
View 4 Replies
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]......
View 3 Replies
Mar 5, 2012
I get the following error when trying to use this code.If you see that something is wrong with my design then tell me. I want to do this the best I can.Also, I am trying to figure out how to add specific players and coaches to a school. I have coaches and players in separate lists just like the school.
Private Sub populateTable()
For i As Integer = 0 To SchoolList.Count - 1
DataGridView1.Rows.Add(SchoolList.Item(i))
Next
[code]....
View 2 Replies
Jun 20, 2012
I'm trying to add objects from a class I created using data from an excel worksheet to a list using a for loop [code]When I run it I receive "System.NullReferenceException was unhandled by user code Message=Object reference not set to an instance of an object."
View 4 Replies
Jul 1, 2010
I have three checkboxes on my datagridview namely, Yes, No, Inv. If the value is set to True in the table which populates the datagridview the respective checkbox is checked and if false unchecked.Now, when on runtime I try to check a checkbox on the Yes Column I receive the followinf error;
DataGridView Default Error Dialog
The following exception occurred in the DataGridView:
System.FormatException: is not valid value for Boolean. -->System.Formatexception: String was not recognised as a valid Boolean.
at System.Boolean.Prase(String value)
at system.componentModel.BooleanConverter.ConvertFrom(ITpeDescriptorContext context. CultureInfo culture, Object value).........
The No and Inv allow me to check and uncheck the checkboxes as many as I want without generating the error.
View 1 Replies
Dec 5, 2010
I am trying to pass a LIKE parameter to a SELECT statement but receive an that strSearch is an invalid field name error:
Private Sub Search()
Dim strSearch As String
strSearch = txtSearch.Text & "%"
[code]....
View 4 Replies
Nov 28, 2009
I have 3 forms 1 -mainform which loads when program is open, and where you select the datafile you want to use and input default information in about 20 textboxes 2 butons 1 to each page 2 -has 3 comboboxes and about 20 textboxes worth of information pulled from the database. then 20 textboxes the user can enter values to compare against the default values coming from form1. and 20 boxes that have calculation results 2 buttons one to each page 3 -same as form2
I created a textbox font format function in form 3
When I load program and click button for form3 everything works fine, i can then click button to take me to form2 and vice versa back and forth no problem
When I load program and click button to form2 I get a date casting error from the function on form 3
Why would I even get this if i havent shown form3 yet??
View 7 Replies
Apr 21, 2009
I am trying to send an email from my program, but am getting an error.The error is: "Mailbox unavailable. The server response was: 5.7.1 Unable to relay"The puzzling thing is that I only get this error with addresses not on our local LAN. This code generates the error:
Private Sub btnSendMail_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSendMail.Click
Dim Message As String = "This is a test message to validate the email transmission
[code].....
View 8 Replies
May 30, 2010
I created an application with some Crystal Reports. I published the application and installed it on the machine which is my develop machine. This machine has Vista on it and is runnig the application 100%. When I install it on a different machine with windows XP, it runs fine until it tries to load the mybase.new. It generates a windows error with no description.
This is a system generated sub:
[CODE]......................
View 1 Replies
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?
View 1 Replies
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
View 2 Replies
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
View 3 Replies
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]
View 2 Replies
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
View 7 Replies
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]...
View 4 Replies
Sep 9, 2011
I've got a project that uses a third party OCX. The OCX was recently updated with a new method. I'm trying to insert code that utilizes that new method:
EPS.Refresh_IO_Link(ControllerRow("ControllerPort"), ControllerRow("ControllerSettings"))
It compiles fine, but when I try to run it from within VS2010 it generates the following error:
'Refresh_IO_Link' is not a member of 'AxEPSIO.AxctlEPSIO'.
This is not true. It shows up in Intellisense, and if I do a rebuild the error goes away. However running it in debug mode always generates the error.I've tried cleaning and rebuilding the solution, but have the same error each time.
View 1 Replies
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....
View 1 Replies
Apr 25, 2011
I have a class that has a property that I declare like this:
VB.NET
Private _DirectoryList As List(Of FileDirectoryInfo) ''' <summary> ''' Array of directories. ''' </summary> ''' <value>Object</value> ''' <returns>Directory array list</returns> ''' <remarks>N/A</remarks> Public Property Directory As List(Of FileDirectoryInfo) Get Return _DirectoryList End Get Set(ByVal value As List(Of FileDirectoryInfo)) _DirectoryList = value End Set End Property
[Code]...
View 2 Replies
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...
View 2 Replies
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
View 5 Replies
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?
View 6 Replies
Mar 17, 2009
i have created my own custom propertythe property is of type collection ,it displays a form which allow the user to add a list of images and strings,it stores the data in a collection ,my problem is , i have noticed that after adding items to the collection at design time , there is no code generated in the .Designer file of the form and there for when i close the for / save it and reload it , all the items that i added to my custom property are gone.my question , what did i miss here ? how do i make my custom property generate code at the .designer file for the items i have added to my property?
View 1 Replies
Jan 10, 2012
If I run my web service code, it generates a serialized XML with only one level, that is,ParentElement and ChildElement. My goal is to make it a multiple XML levels that even grandChild will show, as the sample output below. How can I achieve this using List ollection looping. Do I need to create several functions that returns List objects for each column of the dataset I have?
public List<MyClassEntity> ExtractEmployee(...params here...)
{
...SQL CONNECTION HERE AND SP TO RUN THE QUERY...
[code].....
View 2 Replies
Nov 16, 2009
I have a program in which I display a list of files in a ListView control and then send them all to a printer. I verified that the file is getting from the list to the print routine;however, I cannot seem to get the print function working right. I have tried several methods after reading many forum posts and articles to no avail. I listed my print routine below for reference; I send the file to the ReadFile sub that programatically creates the Print Document and then calls the Print page event. All in all rather simple, but I keep gettting about a dozen lines of blocks and arbitrary characters and then my document starts printing. I thought that by defining the SizeF structure in the MeasureString method and the RectangleF in the DrawString method I would clear up the problems
Private Sub ReadFile(ByVal _pfile As String)
Try
'Dim fs As FileStream
[code].....
View 8 Replies
Jan 23, 2010
I'm not to sure if this is possible this way but I'll try to example what I'm trying to do, I want to raise an event from a class but the class is in a List(Of Collection) for example
A - I have a usercontrol
B - That has Groups
C - The groups have children
The control would be similar to listview/Treeview
Below is the cutdown versions of my classes
Code:
Public Class InfoChildren
Private mText As String
Public Event TextChanged(ByVal Sender As Object, ByVal e As TextChangedEventArgs)
[Code]....
the reason for this is one of the child nodes keeps the current synchronisation time in a project but I need a way to update the text field(I have done this) but refresh the child display?
View 6 Replies
Mar 10, 2011
I have class called GroupSelect and made a collection List(Of GroupSelect)().[code]...
View 1 Replies
Oct 5, 2010
Just trying to print all list collection in a simple routine, variable repeat over and over except for the different collection list:
Dim p2 As New clsTranReq()
p2 = x.Deserialize(objStreamReader)
[CODE]........................
View 2 Replies
