I'm passing a collection of links to a background worker. The first time I use it in my bgw, it works fine, the second time (after a thread sleep) it says property evaluation failed.
View 1 RepliesMy problem is I'm am trying to connect to a db2 table but no matter which connection type is use (adodb, oledb, db2) I keep getting the same error message when I get to this statement: objConn = New (adodb, oledb, db2).connection. "Property evaluation Failed".
View 7 RepliesI am using the code below to export records in a datatable to an excel file using EPPlus.
Dim excelPackage = New ExcelPackage
Dim excelWorksheet = excelPackage.Workbook.Worksheets.Add("DemoPage")
excelWorksheet.Cells("A1").LoadFromDataTable(dt, True)[code]....
However, after walking through the code block, at Response.End(), I get an exception {Property evaluation failed.}
Update:
The error log is:
ERROR: System.Threading.ThreadAbortException: Thread was being aborted.
at System.Threading.Thread.AbortInternal()
at System.Threading.Thread.Abort(Object stateInfo)
at System.Web.HttpResponse.End()
at Reporting.Page_Load(Object sender, EventArgs e) in C:Reporting.aspx.vb:line 38
I tried to update the button text on a form from a backgroundworker.do_work event, and it failed, with the usual cross-thread exception message.However, by pure chance, I also tried to update text in a system.windows.form.toolstripstatuslabel also from this backgroundworker.do_work event, and it DOES work. Question: why is this? Is it perhaps because theres some kind of implicit shared behaviour with system.windows.form.toolstripstatuslabel?
View 4 RepliesI'm using the IsBusy property to determine when a backgroundworker has completed. In the RunWorkerCompleted event I assing the result of the RunWorkerCompletedEventArgs to a public variable within the module where the backgroundworker events reside. The trouble is, the IsBusy property occasionally becomes true before the public variable gets assigned the value of the RunWorkerCompletedEventArgs. I experimented with putting a Threading.Thread.Sleep(10) after the IsBusy property becomes true and it seems to fix the problem. But it really doesn't seem right that I should have to do this. What is wrong here? I have placed the backgroundworker events in a component that is instantiated from the windows form, instead of placing the background worker events within the code of the form itself.
Here is my code;
Function SendAndWait(ByVal IntegerArray() As Integer) As String
Component.BackgroundWorker.CancelAsync()
Do While Component.BackgroundWorker.IsBusy
[code]....
I upgraded a working VB.net windows application from VS2008 to VS2010 (a fairly simple form to process some data) and I get 15 warnings "Load of property 'X' failed" where 'X' refers to what looks like system variables like OutputType, StartObject, RootNamespace, AssemblyName, Option Explicit and so on. I also get two errors pointing to the Form1.Designer.vb file which I is the DesignerGenerated file saying that "My' is not a member of '<Default>'Originally I just used the upgrade wizard, resulting in these warnings. Next I tried creating a new project and adding the relevant files using the VS "Add Existing" function. I have also looked for answers in the forum and on-line but found none. This has got to be something simple I am overlooking.
View 4 RepliesThe property on the error message is a List(Of Person) and for some reason it trigger this error, for almost anything I do, and its getting really annoying.
View 2 RepliesI'm maintaining a set of code that has a wrapper class for SqlDataAdapter to load a System.Data.DataTable. It has a generic function to determine if the DataTable "hasRecords". I know it's a minor issue, but out of curiosity... Which is the faster method to use?
Existing:
Public ReadOnly Property hasRecords() As Boolean
Get
hasRecords = CBool((CBool(BOF = True) And CBool(EOF = True)) = False)
[code]....
If RecordCount is defined as a fixed value in as a recordset property I would think the count would be faster as a single eval vs the multipart conversion/eval BOF/EOF method it is using.
how to clean up the code, perhaps some recommendations on how to have it working optimally. Maybe even some links for areas in particular that I should be more aware of. What functionality have I not employed here that I should have?
Option Strict On
Imports System.Data.SqlClient
Public Class Expenses
Private MotorItems As New List(Of String)
[code].....
in my button click event i ececure
If BackgroundWorker4.IsBusy Then
BackgroundWorker1.CancelAsync()
End If[code]....
after proceess completed if press the button again.i got the following error msg
This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.
When i click on my installed VB.net application icon on the desktop,i receive the message : 'Application failed ti initialize property ox700000000000000 ..... click ok to terminate application'.
View 2 RepliesThis is a bit of an odd one. Last week, this code worked as expected. This week, it does not. Example:
[Code]...
We had a Nullable object must have a value error today on this line of code:list = From x In Me Where x.FooDate.HasValue AndAlso x.FooDate.Value.Date >= barDate
Funny thing is that I feel sure this used to work fine (and there has always been a sprinkling of null values in the underlying data). And logically it looks fine to me. The check for HasValue and the AndAlso look as if they're going to shield us from any Null danger.But it seems suddenly they're not. Am I missing something?OK, we can correct it to this, which eliminates the error:
list = From x In Me Where If(x.FooDate.HasValue, x.FooDate.Value.Date >= barDate,False)
But this looks to me less readable. In simplifying the above code to shorten the line I left out a crucial chunk of the code. The original problem should have read something like:
list = From x In Me Where x.FooDate.HasValue AndAlso x.FooDate.Value.Date >= fromDate And x.FooDate.Value.Date <= toDate
Because of the rules of shortcircuiting and operator precedence (as outlined in an answer to a long ago question of my own) I needed to add brackets round the second part of the instruction in order to stop LINQ evaluating the second x.FooDate.Value.Date:
list = From x In Me Where x.FooDate.HasValue AndAlso (x.FooDate.Value.Date >= fromDate and x.FooDate.Value.Date <= toDate) LINQ really does obey AndAlso and force me to look more closely at the original problem.
I have a system created last year called the "Faculty Performance Evaluation System" in which the students will evaluate their instructors according to their performance. Now I'm trying to change that and the questions are to be loaded from the database. Here are my options for displaying the questions and the rating stars:
1. Using lots of labels placed in the form as well as images(stars)But this will consume lots and lots of codes and the number of questions is limited. Also, I can't do a control array in vb.net unlike in vb6 so it will be very long...
2. Using listview/datagrid?- is it possible to create this project with a listview containing the stars in the 2nd-6th column?, If so, how?
(It's ok to lose my background but the stars can't. Since using this kind of control will make my number of questions unlimited)- then, if I'm to choose this option, how would I save the results into my database? (fields: studnum, category, quesnum, rating)
I'm using Visual Basic Express 2010 and SQL Express 2008 in Windows XP. At first I couldn't add a datasource (the .mdf file for the database) because of a "Operating system error 32" which I seemed to have resolved by giving myself full permissions for .mdf file (by right clicking on the file and going into properties and then Security) and restarting the SQL SERVER (SQLEXPRESS) service. The dataset for the database is in my solution explorer but when I right click on a table adapter to add a query and attempt to open up the query builder, I get the error in the title above.
View 1 RepliesI'm using Visual Basic Express 2010 and SQL Express 2008 in Windows XP.I created a database on my local PC HDD. At first I couldn't add a datasource (the .mdf file for the database) because of a "Operating system error 32" which I seemed to have resolved by giving myself full permissions for .mdf file (by right clicking on the file and going into properties and then Security) and restarting the SQL SERVER (SQLEXPRESS) service.The dataset for the database is in my solution explorer but when I right click on a table adapter to add a query and attempt to open up the query builder, I get the error in the title above.
View 10 RepliesI created a typed dataset a day or so ago, then I added a whole bunch of tableadapter/tables with some relationships etc... suddenly out of nowhere it decides my dataset "is not defined". everywhere in my code where i use this dataset now has an error. I tried not to pull out my hair and do a Clean then Rebuild solution... out of nowhere it just refuses to generate code. Object reference not set to an instance of an Object. It would be nice if it was my object so i could find it but it's not.
Curiously I also lost the little database icon on the dataset in the solution explorer.I can still open it in the designer and preview my queries etc... it just wont make the code. it's driving me insane. anyone got a solution?
I am currently writing a custom control, for a future project. The control uses custom cursors, but sometimes this strange error appears: Code generation for property 'Cursor' failed. Error was 'CursorConverter' is unable to convert 'System.Windows.Forms.Cursor' to 'System.ComponentModel.Design.Serialization.InstanceDescriptor'.
[Code]...
i'm in the need to start a backgroundworker inside another one.Now...The first one BGW starts a for cycle, and inside this one there is the second BGW that has to upload an image to a server.The trouble is that, the progress event and the complete event of the internal BGW are never called.
View 11 RepliesI'm having some very weird issues with interfaces right now.
I have a very simple setup. In one of my class, I have a Property implementing a Property from an Interface.
In my class it's like:
Private _oForm As IForm
Public Property Form As IForm Implements IContainer.Form
Set(value As IForm)
[Code]...
I have like dozens of interfaces like this working throughout my project and I can't believe this simple one can't work!
Get the current number of usage days, unique usage days, etc in an evaluation license using CryptoLicensing Generator.
View 1 RepliesI have written a small game; my first attempt in VB2008ExprEdition.
View 2 RepliesI created a SQL DB named MainDB.mdf and a small VB 2010 application with some forms and datasets.Everything was working OK until i got a new computer and re-installed Visual Studio 2010 and SQL server 2010 on it. I copied my DB from the old to the new computer and also copied by VB 2010 project to it. I used Windows Authentication to connect to the DB in the old computer and also in the new one, i am using different Windows user account names though.
I was able to connect to the DB in the new computer in the Server Explorer section, i created a new connection string to the DB and i can seed there is data in the tables. When i run my VB 2010 application created in the old computer get error:
"Cannot open database "MainDB" requested by the login. The login failed. Login failed for user 'D630Admin'."
I need to get rid of that error and be able to add/mod/del data from my DB using my VB application as i used to.
Is there a way for implementers of an interface where a ReadOnly property is defined to make it a complete Read/Write Property ?
Imagine I define an interface to provide a ReadOnly Property (i.e., just a getter for a given value) :
Interface SomeInterface
'the interface only say that implementers must provide a value for reading
ReadOnly Property PublicProperty As String
End Interface
This means implementers must commit to providing a value. But I would like a given implementer to also allow setting that value. In my head, this would mean providing the Property's setter as part of the implementation, doing something like this :
Public Property PublicProperty As String Implements SomeInterface.PublicProperty
Get
Return _myProperty
[code]....
I searched on the forum / Internet for the solution how a PropetryInfo object (of a Public property) can reveal if it has a Private Protected Setter ... it was all in vain .... all help I found was about how to "Set" value of a public property having a Private Setter.I would like to know if I have a PropertyInfo object of a public property, how would I know if its Setter is Non Public?
I tried, in a exception handling block, where I did a GetValue of the PropertyInfo object and then called SetValue by setting the same value back... but to my surprise it worked well and didn error out.
[Code]...
I'm having a few problems converting some code into VB.NET from C#. Most of the translating is done, but I am getting errors when I try to run my code, and I can't figure out what is causing them. Here is the Sub I translated.
Public Sub CreateWidget()
Dim blue As LCDColor
blue.Red = 0
blue.Green = 0
[code]....
The error I receive on this line ("vision.Widgets.CreateWidget(wg1)") reads "In order to evaluate an indexed property, the property must be qualified and the arguments must be explicitly supplied by the user."
start with I was given a program by a friend that was created in Excel 2003 with the help of Visual Basic Editor. He said he used Visual Basic 2003, which he is not 100% sure about. Anyways he used CurLine in the program and when I try to open it in Excel 2007 and then open the Visual Basic Editor and run the program I get the following error:Run-time error '-2147418113 (8000ffff)':Could not get the CurLine property. Unexpected call to method or property access.
View 2 RepliesI have a very simple class that holds a few public properties - ID, Text, Colour, etc. and a Boolean called 'SelectedItem'. Just like the Checked property on RadioButtons, only one item can have its SelectedItem property set to True within a particular group. Note: there will be several separate groups (lists), each allowed to have only one item with SelectedItem = True.
My first thought was that I would probably just have to handle everything outside of the class, setting SelectedItem to False for every other item in a particular list when another item was selected. But that seems rather inelegant to me. So I've been trying to think of how this might be done within the class. For example: could I perhaps have a private string property called say "GroupName" - set in the New sub when adding a new instance of the class - and then use a private shared method to set every item's SelectedItem property to False, provided the item has the same GroupName as the newly selected item? I would have a go at doing this but I have no idea how to enumerate every instance of a class from within that class, or whether that's even possible. Is it? Or is there another (better) way to achieve my goal? Here is a cut-down version of what I've got so far:
Public Class ResourceItem
Public ID As Integer
Public Text As String[code]....
As can be seen: instead of instantiating a new ResourceItem and passing that as an argument to the manager's Add procedure, I'm simply passing the details of the new item and the procedure is creating the item from those. I don't know whether this is a good or bad idea - please advise - but I've done it because I couldn't figure out how to make the SelectedItem property only writeable by the manager, so I wanted to avoid having directly accessible objects that could have their SelectedItem property set to True without it deselecting all the other items in the same group. Of course that still leaves the possibility of setting a variable to one of the manager's list items and setting it from there, so I would still like to know how I could prevent that, if possible.
UPDATE: I didn't use the code above in the end, deciding instead to go with Cyborgx37's solution - which seems to work perfectly well for me despite the warnings about best practice. I also realised I would need to use the same class in another scenario where multiple items could be selected, so it was easy to add a Boolean property to the manager to enable that.
Using the following code I get Identifier expected and Property access must assign property or use its value errors:
ViewState["SomeKeyValue"]
What is wrong with this code?
I have a dataview an i would like to show the count property in a text box.
i tryied the following
me.textbox1.DataBindings.add(new DataBindind("Text",DataView,"Count"))
But i have a exception.