.net - Already Defined Delegate?
Feb 11, 2010I heard once that .net introduced an already defined delegate with no parameter that we could use instead of creating one.
View 1 RepliesI heard once that .net introduced an already defined delegate with no parameter that we could use instead of creating one.
View 1 Repliesfrom the documentation we have this: Multicast Delegate: Represents a multicast delegate; that is, a delegate that can have more than one element in its invocation list.
so am i right to say that Multicast delegate is no different from a normal delegate other than the fact that it has arguments. so System.Action is a 'normal' delegate whereas System.Action(T)(Byval obj as T) is a multicast delegate?
I've created a Delegate that I intend to call Async.
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Code:
Public Class SendPings
Shared Sub New()
AddHandler Post.Saved, AddressOf Post_Saved[code].....
I get a error" Method 'Private Shared Sub Ping(item As BlogEngine.Core.IPublishable, itemUrl As System.Uri)' does not have a signature compatible with delegate 'Delegate Sub WaitCallback(state As Object)'.
I am trying to redirect command line output to a list box in a vba macro, and I've found some code that I think might point me in the right direction, but I keep on getting the same error. When I use this code [code]It gives me the error in the title and highlights the first declaration line.What does it take to define a new "process".
View 1 RepliesI am trying to write a VB.NET alternative to a C# anonymous function.I wish to call Threading.SynchronizationContext.Current.Send which expects a delegate of type Threading.SendOrPostCallback to be passed to it. The background is here, but because I wish to both pass in a string to MessageBox.Show and also capture the DialogResult I need to define another delegate within. I am struggling with the VB.NET syntax, both from the traditional delegate style, and lambda functions.My go at the traditional syntax is below, but I have gut feeling it should be much simpler than this:
Private Sub CollectMesssageBoxResultFromUserAsDelegate(ByVal messageToShow As String, ByRef wasCanceled As Boolean)
wasCanceled = False
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a messagebox appear that show user-defined type not defined i had try another code but it still same error.. i'm using vb6
Why isnt this working?Sub Macro1()
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i am trying to read an existing excel 2007 file from vb.net i used a form with single button and i written code in button click event code is :[code...]
View 1 RepliesWhile reading this threadthe code sample there came from MSDN, which was used to demonstrate the use of a delegate. I know what Delegates are. And I know how they work when it comes to things like crossing threads and even sinks.... how ever, the sample given is a simplecontrived example, and I'm wondering why/when would I use a delegate in this situation? Or in any situation? In my head, it seems it would have been easier/cleaner to call the function pointed to directly...
View 18 RepliesI came across a snippet of C# code which is very useful. I am trying to convert it to VB.NET, but can't seem to.
timer.Tick += delegate { panel.Children.Add(source); timer.Stop(); };
Is it possible to translate this to something similar in VB?
I have below code in C#:
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I'm having trouble converting a C# delegate to VB.NET.
How can this be done?
public MainForm()
{
InitializeComponent();
_twain = new Twain(new WinFormsWindowMessageHook(this));
_twain.TransferImage += delegate(Object sender, TransferImageEventArgs args)
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how can I convert the following code from C# to VB without exposing "variable" as global variable.
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I'm in the process of converting some existing code to VB. However, I'm running into a bit of a snag. It seems that in C#, a delegate can have a return value, but not so in VB. So my question is, how would I convert the following VB code to handle this?.[code]
View 3 Repliesim developing a way of calculationg differentil equations in VB 2008 using the 4th order ruge-kutta method. I pursched a book by Jack Xu called "Practical WPF Graphics programming".
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how this is written in VB.NET? This was an example I found on [URL]
ThreadPool.QueueUserWorkItem(delegate
{
var channelFactory = new ChannelFactory<ISimpleService>("*");
var simpleService = channelFactory.CreateChannel();
var asyncResult = simpleService.BeginGetGreeting("Daniel", null, null);
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I am using this delegate to invoke my methode:
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for few solutions it work outs well but not for the following code. I find an error when executing the following code. I find an error :
ErrorMethod 'Public Sub test()' does not have the same signature as delegate 'Delegate Sub DataRowChangeEventHandler(sender As Object, e As System.Data.DataRowChangeEventArgs)'.C:UsersKashifDocumentsVisual Studio
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I have a problem in translating a piece of C# code
(
http://www.codeproject.com/KB/WPF/VMCommanding.aspx)static bool ConfigureDelayedProcessing(DependencyObject depObj, ICommandSink sink) { bool isDelayed = false;
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I am trying to create a delegate(as a test) for: Public Overridable ReadOnly Property PropertyName()As String My intuitive attempt was declaring the delegate like this:
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So the question is, how do I make a delegate for a property?
This is a theoretical question, I've already got a solution to my problem that took me down a different path, but I think the question is still potentially interesting.Can I pass object properties as delegates in the same way I can with methods? For instance:
Let's say I've got a data reader loaded up with data, and each field's value needs to be passed into properties of differing types having been checked for DBNull. If attempting to get a single field, I might write something like:
if(!rdr["field1"].Equals(DBNull.Value)) myClass.Property1 = rdr["field1"];
But if I've got say 100 fields, that becomes unwieldy very quickly. There's a couple of ways that a call to do this might look nice:
myClass.Property = GetDefaultOrValue<string>(rdr["field1"]); //Which incidentally is the route I took
Which might also look nice as an extension method:
myClass.Property = rdr["field1"].GetDefaultOrValue<string>();
Or:
SetPropertyFromDbValue<string>(myClass.Property1, rdr["field1"]); //Which is the one that I'm interested in on this theoretical level
In the second instance, the property would need to be passed as a delegate in order to set it.
Try5Times will try a function for 5 times.that function can have any number of argument and return a boolean.
If the function return false, try again.
If the function return true, stop.
How to make such function and delegate? Is there a general delegate?
Here there's an old question about this code.
xmpp.OnLogin += delegate(object o)
{
xmpp.Send(
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I'm trying to convert the c # code of a sample code to vb.net but I could with the following line of code. it is an event, delegate. but I can not build a functional structure.
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I have a code from Fleck that actually works fine in the C# (no errors)and this is a line in a class library:[code]can someone tell me what is the valid vb .net code for that?
View 1 RepliesI've got interface:
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I'm having an issue with an application suite I'm developing. The bulk of the work is done in a backend dll that relies heavily on delegate subs in the different apps.
The problem I'm having is, I have a lot of these delegates typed to require a parameter. (eg, Public Delegate Sub DelTypeA(ByRef param As Object)). The individual methods will have a DelTypeA as one of their params, and I will pass it AddressOf functionA that has that signature.
This works fine for strong typing as long as the signature is something incorrect (2 params, a byval instead of a byref). But if functionA has NO params, the delegate is still created!
This works fine if I genuinely don't need to use a param, eg if the sub is simpler and I would have ignored the param anyway. But I want the strong typing to work here.
EDIT: I should add that invoking the delegate also works fine for simpler subs; the param is just not passed because it had nowhere to go. But I want to force all the subs to match the signature and do their own ignoring of the param
I've been fooling around with this for two hours and getting nowhere. I want to update a list box on a form with some text. Unfortunately the event that calls for the update is a timer which gives me a cross thread error.The listbox relies on a combo box which tells it the number of items to display. Here's my sub that performs the update.
Public Sub EventUpdate(ByVal EventMsg As String)
Dim DateTimeStamp As String = Format(DateAndTime.Now, "MM/dd hh:mm:ss")
With lbxEvents
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I have one master page and then content page on the master page and also have one UC on the master page, now i want to filter data from usercontrol on and populate on content page using delegate.
I have achieved this in C# but i am not able to do this in VB.NET
Because in VB.NET i am not able to overload event of the uc.