Detect A Property Of Type "InvalidOperationException" Within A Collection?
Nov 11, 2010
Consider the following vb.net code for an office add-in (for access):
td = db.TableDefs(objectName)
For Each fld In td.Fields
For Each fldprp In fld.Properties
[code]....
the variable "db" is a .net representation of the access vba return result from "Application.CurrentDB()". "td" is of type "DAO.TableDefClass".This code throws an exception of type "InvalidOperationException" when the value of the fldprp.value property cannot be determined (in Visual Studio, it shows the value as {"Invalid Operation."} in the watch window). fldprp.name, however, is available.
There are only a few properties which this occurs on. I'd like to be able to loop through all the fld.properties and output the values, but ONLY if it is not an exception. I am pretty sure why it is happening (certain properties are not available in this context). What I need to know is how to detect this at run-time so i can skip the property.
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Mar 8, 2012
I am creating a User Control where I have a property called Items. Items is of type LibraryPanelBarItem Collection (custom class) which contains a collection of LibraryPanelBarItem objects. I would like to be able to add these at design time by using the Collection editor that VS uses for adding things such as treenodes/listviewitems. Ideally I would also be able to declaratively add them to the html syntax. I can get the Items property to show up but I get no intellisense to add the items between the opening and closing tags. [Code]
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Sep 14, 2011
I know its generally a big No-No to modify a collection that you are iterating through but unfortunately i didn't design the code that i'm trying to modify. All over the place the following is done:
for each log in Logs
logs.Delete(log.LogId)
Next
Delete pretty much just deletes the log from the database and removes it from the collection. Previously the Logs object was using a Non-Generic collection. I changed it to use a Collection(Of Log) so i can LINQify the object. Now every time i call next/.MoveNext is called after the first delete the following error happens:
InvalidOperationException:"Collection was modified; enumeration operation may not execute."
I understand why i'm getting the error but i don't understand why it never happened with the Non-Generic version. Is there anyway to get around this error? There really is no way i can take the time to change every place where the delete logs like this (codebase is large). Id like to just remove the code in the Delete function where it removes it from the current collection because i'm assuming no code does anything with the collection after its done but you know what happens when you assume.
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Jan 8, 2010
This was working on the last test, now it's throwing an InvalidOperationException saying Update requires a valid InsertCommand when passed DataRow collection with new rows. No change in this
Dim NewRowB as DataRow=dsBatch.Tables("Batch").NewRow
dsBatch.Tables("Batch").Rows.Add(NewRowB
daBatch.Update(dsBatch,"Batch")
What *has* changed is that I'm trying to fix the same error that's occurring on a different dataset in a different form. This should add a blank record to the dataset, then update the database. The blank fields allow nulls. The reason for this (and there may be another way to do this-I'm helping a novice fix up his code and, since this has been working, I haven't yet really looked at it) is to obtain the correct value for an identity field. We've found that when the row is added to the dataset, if it doesn't currently contain any rows, the identity value is set to zero-but when the database is updated, it gets a different value (because previously inserted rows have been deleted). So we update the database then retrieve the correct identity value before continuing.As I said, this was working fine-until I started working on the same problem occurring in a different dataset. So why would that affect this dataset?
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Sep 5, 2010
I defined a picture column as Image type. Created the Datasource and placed an Image control on a form. When I input the picture of a client in the input form every thing works fine but when I Open a second form (the search form) and try to search for a client with picture I get the following message:Inconvertible type mismatch between SourceColumn 'Picture' of Byte[] and the DataColumn 'Picture' of String
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Mar 29, 2010
I have several ActiveX controls in my project one of them loads solidmodeling files for viewing. Because this process can take some time the authors provided an OnFinishedLoadingDocument event.This worked fine under VB6.Now however under VB.NET 2008 framework 3.5 I get an exception thrown When I try to access a form control from this event.
Quote:
A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll I found an article that says something about it.
Quote:
If you are using ActiveX controls on a form, you may receive the cross-thread InvalidOperationException when you run under the debugger How can I add text to my control from this event?
Code:
Private Sub oView_SW_OnFinishedLoadingDocument(ByVal sender As Object, _
ByVal e As AxEModelView._IEModelViewControlEvents_OnFinishedLoadingDocumentEvent) _
Handles oView_SW.OnFinishedLoadingDocument
Dim nSheet As Integer = 0
[code]....
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Aug 8, 2011
I've reviewed the links that were offered and don't find an answer. Neither has a lot of searching helped, probably because I can't think of a reasonably short way to ask the question. I hope that I've at least found the proper forum and category.
In my VB 2010 code, I've defined a structure that has about 30 elements. I want to sum the properties (they are all singles) of two members of the corresponding collection. I understand that I can do something like:
member1.property1=member2.property1+member 3.property1 for the entire set of properties of member2 and member3 to produce a completely defined member1 What I wonder is whether or not there is a way that uses fewer lines of code - I know that I can't do:member1=member2+member3, for example.
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Dec 26, 2010
I'm trying to make this example (translated to VB) and i'm getting an error when i try to view in browser [URL] I have uploaded it to Skydrive
[Code]....
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Jan 16, 2010
I'm trying to create an inherited version of the ListView control that (among other things) should have a different background image if the listview is empty to if it has items.Obviously you can easily enough test the count of the collection, but I need to be able to react to the event, however there doesn't appear to be any event related to adding/removing items.
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May 5, 2011
I am using VS 2008, Office 2007, and Win7 Home Premium on my system.I have a simple application which should be a breeze to build. All I am attempting to do is pull data from an Access database with four small tables into a data grid on a windows project. Should be simple, set up the data connection, choose a datagrid from the table in the data source view, drag it onto the page and done, right?I can't get it to work. It will all work fine until I attempt to run or debug the project. The data will not show up. The data grid does, but I get this error: A first chance exception of type 'System.InvalidOperationException' occurred in System.Data.dll
As I said, the project seems to build fine, but it will not pull the data. After the initial build I get the message that Windows will show this page in Compatibility View. Is it something with Win7 Home Premium, or a setting somewhere?
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Feb 12, 2011
A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll It displays in my Immediate Window when i run my program, I'm using a text reader to read a number of XML files using background worker...most the time it stops so something is wrong but sometimes it works fine.
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Jun 11, 2009
what does "A first chance exception of type 'System.InvalidOperationException' occurred in System.dll" means? it occur after the bold sentence of my program.
Dim count As Integer = 0
Dim missing As String = "Missing Ingredient:"
For Each strStore In strDownload
If Not strDownload Is Nothing Then
[code]....
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Mar 11, 2010
I've got a webservice serialization issue that is causing quite a headache and am hoping to get a little assistance before I end up pulling my hair out or something equally drastic.
[Code]....
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Jul 14, 2009
I have class called "Employee" and I have a class called Department. They have an association. I need to create a colleciton of employees with the creation of a Departmant. I know how to do with using "private" member _AllMyEmployees. But I need to expose this private member using properties. therefore how do i covert thsi private member to a property? [code]
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May 19, 2011
How to detect if a particular control has a particular property?
I am considering writing a generic routine and I would like to know how you can detect whether a particular object has a particular property?
Something like this code:
If HasImageProperty(myObject) = True Then
EndIf
I guess reflection would be used here, but I am not very familiar with reflection.
[Code]....
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Dec 16, 2011
I am trying to make it so when I use Me.Controls("Timer1") for example I can access specific commands for a timer such as Stop() Start(), I tried CType() and typed in "Timer" as the type but it says the control type can't be converted to the "Timer" type.
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Nov 15, 2011
I have some nested objects arranged like this:
Process
Persons
Workflows
Tasks
So you have one Process. Then multiple Persons can be added to and multiple WorkFlows can be added Process as well. Multiple Tasks can be added to each WorkFlow but I need a way to tie which Person is doing each task. I basically need a way that for each Person added to the Process it, in it's constructor, assigns a Person.ID property that can then be assigned into each Task's PersonID property...
Dim myProcess as New Process()
Dim myPerson as New Process.Person()
myProcess.AddPerson(myPerson)
[code]....
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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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Nov 14, 2011
Ive recently written a control called a ButtonRow in VB.NET that allows you to dynamically place buttons on it through a typed collection property. The property itself is tagged with the <DesignerSerializationVisibility(DesignerSerializationVisibility.Content)>. However it works really bad. First of all, whenever you add buttons to it and you delete the controlafterwards, the designer code file still have the buttons declared but without the aButtonRow to who's collection they would be added. Secondly, you cannot copy the controlfrom one form to another. It would just copy the ButtonRow object without the buttons
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May 26, 2012
I'm working on a small project and got into some troubles trying to keep it OOP.I have a global variable:
Public Stations As New Microsoft.VisualBasic.Collection()
And 2 classess: Station & Unit:
Public Class Station
[code].....
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Feb 2, 2009
I had read on pages like this
that when adding objects to a CheckedListBox, it takes the .ToString() function of each added object as the text string.
I added instances of SortedDictionary as this[code]...
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May 15, 2012
I have a requirement where I need to have a "type safe" way of accessing property names, without actually instantiating an object to get to the property. To give an example, consider a method that takes as arguments a list of IMyObject and a string that represents a property name (a property that exists in IMyObject).
The methods implementation will take the list and access all the objects in the list using the property name passed... for some reason or another, we won't dwell on that!!
Now, I know that you can do this using an instantiated object, something like ...
Dim x as MyObject = nothing
Dim prop As PropertyInfo = PropHelper.GetProperty(Of MyObject)(Function() x.MyProperty)
Where my helper method uses reflection to get the name of the property as a string - there are numerous examples of this flying around on the web!
But I don't want to have to create this pointless object, I just want to do something like MyObject.MyProperty! Reflection allows you to iterate through a types properties and methods without declaring an object of that type... but I want to access a specific property and retrieve the string version of its name without iteration and without declaring an object of that type!
The main point here is that although I am trying to get the property name as a string... this is done at run time... at compile time, I want this to be type safe so if someone changes the property name, the compilation will break.
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Apr 27, 2010
I 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.
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Aug 12, 2011
I have an object with a property that is a collection. When I point the PropertyGrid to the object it displays the ellipses for the collection. When I click it I get the generic collectioneditor. Of course the Add put fails because my collection is strongly typed. I need an example of how to create a collectioneditor that will create my collection's objects.
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Jun 17, 2010
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].....
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Nov 18, 2011
I'm trying to create a datagrid with auto generating columns. Let's say my Collection is a property named Articles of my viewmodel of type ObservableCollection<ArticleWrapper>.
I bind now the ItemsSource to this collection:
<wpf:DataGrid ItemsSource={Binding Articles} />
The class ArticleWrapper is like this:
[c#]
public class ArticleWrapper
{
public ArticleConfigurationSet ArticleConfigurationSet { get; set; }
public string Description { get; set; }
[Code]....
But now my problem: I want to bind the displayed data to my ArticleConfigurationSet property. But I cannot change my ItemsSource Binding, because the SelectedItem property of the datagrid must be of ArticleWrapper (for command handling).
The datagrid should also look like this:
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Feb 13, 2010
I have two tables "Person" and "Alias" in a one to many relationship. I have a DGV for "Person" and want to use a combobox for the Aliases. I also have a textbox and a button for the user to type the alias name and click the button to add the alias name to the combobox and update the dataset. I keep getting the "Items collection cannot be modified when the DataSource property is set." Error. But if i use a DGV instead of a combobox for aliases, I have no errors and everything works fine. If I remove the datasource property for the combobox it will not get populated with the data already entered, so how, or can I, set it up where the combobox gets populated when the form loads and able to add items to the combobox????
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Aug 26, 2011
Like i want it to read the lines i have in the text file but i get an error Each time i press the button Why?
Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
Dim objreader As New System.IO.StreamReader("C:UsersJamesDesktopMusicas.txt")
Do Until objreader.EndOfStream
[code]....
Error:
Quote:
Items collection cannot be modified when the DataSource property is set.
Error line
Quote:
ListBox1.Items.Add(objreader)
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Jul 6, 2009
During a code review I looked at set of repository classes (in vb.net). I am used to seeing these repository classes full of functions that return collections (among other things) of your domain objects. However, this repository had 1 public property and 1 private variable that looked something like this:
Private _item as Collection (of Customer)
Public Item as Collection (of Customer)
Get...
Set...
In the "Get", there is code that gets a the Customers from the DAL and loads it in the private _item. What would the benefits be in using a property (customerRepository.Item) instead of plain old function (customerRepository.GetAllCustomers)? The "Property" way looks odd to me but odd doesn't always mean wrong.
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May 16, 2012
GetDocumentType() works fine but adding into the collection cause error, it is not adding anything into it.
Imports System
Imports System.Collections.Generic
Imports System.Collections
Imports System.Collections.ObjectModel
[Code] .....
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