Wpf - DependencyProperty Callback-Method Not Called
Nov 29, 2009
I create a UserControl (TableWithFilter.xaml) with a dependency property (source). The UserControl is a Table with a source property for the different items. I created the XAML and set the source property via the XAML Binding. So far so good.
But if the value of the dependency property is changed, the defined callback method is not called. Therefore I cannot update the entries in my table. Has anyone an idea why the callback method is not called?
Here is the definition of my property in the class "TableWithFilter":
Public Shared ReadOnly SourceProperty As DependencyProperty = _
DependencyProperty.Register("Source", GetType(List(Of TableViewItem)), GetType(TableWithFilter), _
[Code]....
If the attribute "ContentList" is changed I expet that the "ChangeSource" method in the TableWithFilder class is called. But this is not the case. After I changed the ContentList attribute, I Raise the following Event:
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("ContentList"))
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Nov 25, 2011
I have a large problem with inheritance in vb.net. The problem is the following:
I have 2 forms => frmBase and frmChild
In frmBase i want to create a method Called StartWorking() and i want frmChild to inherit this method.
But here is the tricky thing: when frmChild.StartWorking is called i would like the following => without calling MyBase.StartWorking()
I want frmBase.StartWorking() to be executed first and after a test in frmBase.StartWorking if blnValue is true then frmChild.StartWorking has to be activated. if blnValue is false that frmChild.StartWorking cannot be activated.
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Nov 15, 2009
I have a method that is asynchronously called when System.Net.Sockets.NetworkStream.BeginRead completes.
skDelegate = New AsyncCallback(AddressOf skDataReceived)
skStream.BeginRead(skBuffer, 0, 100000, skDelegate, New Object)
In that callback method, I need to interact with the UI thread.
Sub skDataReceived(ByVal result As IAsyncResult)
CType(My.Application.OpenForms.Item("frmMain"), frmMain).refreshStats(d1, d2)
End Sub
This causes an exception after the method completes. (when End Sub is executed)
[Code]...
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Mar 1, 2011
I have the below code. What happens if the Upload method takes more than one minute for completion? Does the timer kick off another call to the Upload method immediately after one minute is over or Does it wait until the method finishes executing? I am implementing this as a windows service.
Protected Overrides Sub OnStart(ByVal args() As String)
Dim tmr As Timer = New Timer(New TimerCallback(AddressOf Upload), Nothing, 1000, 60000)
While Not tmr Is Nothing
[code]....
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Jul 28, 2009
I have a windows form that gets data from a scale via the serial port. Since I need the operator to be able to cancel the process I do the get data process on a second thread. The data collection process gets multiple readings from the scale one at a time. The form has a label that needs to be updated with information specific to each reading.
I call the method to get the data from the scale with this code.
Dim ad As New readALine(AddressOf thisScale.readALine)
Dim ac As New AsyncCallback(AddressOf Me.GetDataCallback)
Dim iar As IAsyncResult = ad.BeginInvoke("", ac, ad)
The delegate for the readALine method is defined in the UI code.
Delegate Function readALine(ByVal toSend As String) As String
The GetDataCallback method:
Private Sub GetDataCallback(ByVal ia As IAsyncResult)
.
.
.
lblInstructions.Text = _thisMeasure.dt.Rows(_currRow - 1).Item("cnt") & ":"
lblInstructions.Refresh()
.
.
.
End Sub
I get the exception on the "lblInstructions.Text =" statement. I thought the GetDataCallback method was part of the UI thread so don't understand why I'm getting the exception. I know this could probably be rewritten using a BackgroundWorker and it's appropriate events but for now would like to understand why this isn't working as expected. The application was written originally in VS2003 and just recently upgraded to VS2008.
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Mar 26, 2010
i have the following property declaration
[Code]...
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Apr 4, 2011
i have problem when addnew row at keyup event for datagridview control. i want to add one row when method addRow() called.
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Dec 14, 2011
I'm working with a VB.Net page which calls a web method from JavaScript, this was working upto a week ago and now for some reason is not working.
Firstly my page generates a list of items that can be clicked, The line that does this is:
TicketHTML = TicketHTML + "<td><img src='../images/delete.png' Class='imgTicketClose' alt='Delete Task' onclick='DeleteTicket(" + row("id").ToString() + ")' /></td></tr>"
I know this is working as when the item is clicked I get a javascript popup so I would assume the problem is not here.
Now my Javascript:
function DeleteTicket(ticketID)
{
var answer = confirm("Do you really want to delete this task?")
[Code].....
EDIT: Could anything in the web.config file be preventing page methods from executing? I have just noticed this happening with a completely seperate web method and have checked the integers being passed into the javascript with an alert() and they are all valid
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Dec 30, 2010
I have a class which i realized will not always correctly instantiate and as a quick fix, i figured i'd subclass it and shadow a few methods so that the program can continue to run without exploding. When i run the software, calls to the methods resolve to the base's implementations and not the subclass. I'm using VB.NET with .NET 2.0. Here is an example of what i'm trying to do[code]....
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Aug 2, 2011
When I put a breakpoint in a method I'm calling from a lambda expression, the breakpoint is never hit. When I move the method call outside the lambda, the breakpoint hits.
For example:
Function IncrementAll(ByVal items As IEnumerable(Of Integer)) As IEnumerable(Of Integer)
Return items.Select(Function(i) Increment(i))
End Function
[Code]....
If I call IncrementAll, the breakpoint in Increment does not get hit. Is there a way to make VS 2008 stop on these breakpoints? I hate the thought of rewriting all my LINQ into loops just for debugging.
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Sep 26, 2010
I am trying to use the AAA syntax in Rhino Mocks with VB.Net to validate that a method was called only one time. I can't seem to get it right. With this code, if the repository is called twice, it returns nothing on the second call, and the test passes. I would have expected the test to fail when VerifyAllExpectations was called.
<TestMethod()>
Public Sub GetDataCallsRepositoryOneTime()
Dim repository As IDataRepository = MockRepository.GenerateMock(Of IDataRepository)()
[Code].....
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May 25, 2012
I am trying to convert a DLL function call which has the Callback function routine called within the DLL function call.The DLL function call signature is like this:
typedef void *HANDLE;
typedef HANDLE HACQDESC;
DECLARE_HANDLE (HWND);
[code]....
how to convert this DLL call to VB.NET and also how to create the callback function and send it as parameter to this function
call.
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Jun 22, 2011
I have a class that has a destructor and a Dispose method (I also inherit IDisposable). Why is it that the only time my destructor gets called is when I call GC.Collect()?
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Nov 11, 2009
How do I force the Visual Studio compiler to generate an error when a required method is not being called in the constructor of a child class? Like when you edit the form designer code, the compiler complains when InitializeComponent()isn't the first call in the constructor of a form. Is this even possible in VB.NET?
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Sep 11, 2010
I'm wondering if there's a way to programatically reference the class that called a method in another class. Let me give you an example:
Public Class OriginalClass
Private Sub Main()
Log.PgInit()
[Code]....
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Nov 29, 2010
I'm trying to write a method that is called from a variety of forms at load. So with a Form1 load event I would call the following:
Dim testpoint As New Point(10, 20)
DrawVerticalStringFromBottomUp("Hello", testpoint, Me)
The DrawVerticalSTringFromBottomUp Method is as follows:
[Code]....
When I call the code at a form's load event, nothing happens. When I call it from a button click after the form has loaded it works! I know this should be called from the paint method, but that doesn't suit my purposes.
way to make this work from the form load event?
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Aug 26, 2010
Scenario: A VB6 library calls a method in a .NET-Assembly through COM and with that opens a WPF-Dialog, which is contained in another .NET-Assembly that is early bound. This WPF-Dialog got a complex master/detail implementation over a DependencyProperty of type ObservableCollection on this dialog. The DependencyProperty looks something like this:
public static readonly DependencyProperty ThatDependencyPropertyProperty =
DependencyProperty.Register("ThatDependencyProperty", typeof(ObservableCollection<SomeClass>)
[Code]....
Problem: After this dialog gets closed through setting DialogResult and is being completely re-instantiated, this DependecyProperty still got it's values and the dialog is still displaying the previous master/detail information. My current workaround is to simply let the dialog clear the collection in it's ctor, but I certainly don't like this... what could keep this collection alive through two instantiations?
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Jul 7, 2010
I'm trying to make a mouse over for a stack panel in WPF using a custom DependencyProperty (StackPanels do not handle the MouseEnter event).
I've created a class for the DependencyProperty like so:
Public Class MouseEnterBehavior
Public Shared Property MouseEnterProperty As DependencyProperty =
DependencyProperty.RegisterAttached("MouseEnter",
[Code]....
I was able to get the code to compile and run, however the binding doesn't occur.
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Jun 3, 2010
I am trying to learn how to create relations I got a sample from a web site and it works great, but when I tried to make one; it is not working. Can some one tell me what I am doing wrong. It gets down to the last relation that I made called "ProdDet" and jumps out of the whole method. The error message says the following:
System.ArgumentException: These columns don't currently have unique values.
at System.Data.ConstraintCollection.AddUniqueConstraint(UniqueConstraint constraint)
at System.Data.ConstraintCollection.Add(Constraint constraint, Boolean addUniqueWhenAddingForeign)
at System.Data.ConstraintCollection.Add(Constraint constraint, Boolean addUniqueWhenAddingForeign)
[Code]...
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Feb 9, 2011
i was wondering if it possible to have a condition where lets say you have a column in the datatable called amount and a textbox acting as the filter called say maxamount to set it so the rowfilter when filtering the table will sum the number in the amount column until the number in maxamount is met, then stop and only return the rows where the total sum of the amount column is equal or less than the maxamount value, so i guess if the next row takes us over the maxamount it discards this row and returns the rows previous to it. is this possible using datagridview rowfilter or should i be loooking elsewhere to achieve this?
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Jun 5, 2011
I have an sql table called Stock with two fields called StockID and StockCode. I want the user to select the stockcode from a combo which in turn populates the stockid for that item into a lable on my form. I have already populated the stockcode into the combo but dont know how to compelte the rest.
Imports System.Data.SqlClient
Public Class cbo2
Private Sub cbo2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[CODE]...
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Aug 11, 2009
I have a form called FrmPracDetails which is built up with a List view called LvwColProc. Therefore when you click a field on the LvwColProc it takes you to another form called FrmColProcessing, here you can make changes to certain fields which are also present on FrmPracDetails. What I want to do is when you make changes on FrmColProcesing and Click the Save Button (which calls the Save function)the changes appear instantly on FrmPracDetails. Please note, FrmColProcessing will always be open next to FrmPracDetails. I have tried to put this code in the Save function present in FrmCol Processing as shown below, but it doesnt Refresh FrmPracDetails form. [code]
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Apr 2, 2012
I have the following line of code in my program:
JCL_History.Enqueue(JCL_History(I))
This JCL_History object is basically a Generic.List encapsulated in a wrapper and has the following method:
Public Sub Enqueue(ByRef value As String)
If Members.Contains(value) Then
Me.RemoveAt(Members.IndexOf(value))
[Code].....
In my testing I have 2 items in this JCL_History list. When I call that first line of code I posted (the one that invokes Enqueue) with I = 1 I expect the first item to be shuffled to the bottom and the second item to be shuffled to the top.
After the thread returns from Enqueue I notice that this is exactly what happens to my list, HOWEVER if I hit the "step_in" button after the execution of Enqueue I go into the Default Property's set method where Index = 1 and value = and it screws everything up, because the item that got shuffled to the end (index 1) gets overwritten by the item value shuffled to the top.
So basically the set method on the default property is getting called at what I think to be a completely ridiculous time. What gives? By the way I'm running VS2005 on XP.
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Apr 11, 2012
Can you look at my coding and let me know what I'm missing or doing wrong?I have a SSRS report that is called from a ReportViewer control and the ProcessingMode for this control is Remote. The report also has 1 parameter in it's DataSet.In the code I placed a MsgBox to make sure the code is finding the parameter and returning the parameter name. I am trying to stick the value of 10 into the parameter for playerID 10. Data for this player does exist.
I believe I need to add some more code to make this work but I'm not sure what else to add.
When the code executes the report is displayed but no data is shown in the report.
[Code]...
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May 13, 2010
I recently found an awesome tool called "Freemind" that is called a 'mind mapping' program. It's similar to MS Visio but way cooler and more automated.I reeeallly would like to integrate this into a VB.net Form, but how?
Has anyone seen or heard of mind mapping inside VB.net before? Are there programs out there already that work with VB.net or anyone have an example they have seen / built that works?
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Oct 19, 2010
Consider a MyForm class that contains a shadowed implementation of Show(). It also contains a CreateForm() method, which accepts an instance of the form and calls the shadowed sub:
[Code]....
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Jun 19, 2012
I'm trying to use a .DLL which Callbacks a Function of my project, but I can't get it to work.
Declaration from .h file of .DLL
void DLL_EXPORT SetEntity_CallBack(bool Active, _
void (*Entity_Callback)(int Site, int Application, int ID, _
[Code].....
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Aug 17, 2009
I have this code obtaining data from a sensor that is sending a string that contains 4 numbers separated by a tab and terminated by an end of line/ I am trying to use an asynchronous callback to get the data over TCP. That problem is that the callback function is not grabbing the complete string. Sometimes it will, other times it gets half in one retrieve and half in another. I need the callback to hold off until it gets a newline character.
Code:
Public Sub readVaisala()
Dim ip As String = "192.168.1.30"
Dim portNumber As Integer = 23
Dim time As Int32 = Now.Second * 1000 + Now.Millisecond
[code].....
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Mar 3, 2011
I have a C++ dll that contains a callback. The callback has one parameter that is passed in and one parameter that is passed out. The parameter that is passed from C++ is a variant. So, we are going from a variant in C++ to an object in VB.NET. The function works. However, It seems that there is a memory leak on the VB.Net side. This must be a Marshaling issue. I have tried to use the MarshalAs Functions, but to no avail.
VB.NET
Declare
Function EnableWriteNotification
Lib
[code]....
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Jan 4, 2011
there is error when i use callback function A callback was made on a garbage collected delegate of type 'skynet1!skynet1.Form1+myCallBack::Invoke'. This may cause application crashes, corruption and data loss. When passing delegates to unmanaged code, they must be kept alive by the managed application until it is guaranteed that they will never be called.
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