Using Delegates To Pass Information Back To UI From Custom Socket Class?
Oct 6, 2010
I am in the process of prototyping a small sockets application, which monitors IT infrastructure (due to in-house financial and deployment restrictions, I am unable to utilise an existing commercial or open-source solution). Basically, I have a server application and associated agent process for communicating heart-beat data to the server. The server application implements a TCP socket class (TCPDevice), which is called from a WinForm. I am aware of the restriction on updating the UI from processes running on separate threads, and that the preferred technique for acheiving this is via the use of Delegates in conjunction with the Invoke method. Having had very little need previously for using Delegates (apart from of course std windows events and the BackGroundWorker control), I am at a loss as to how to do this in the context of my application, and would appreciate some assistance, although it has occurred to me that I could use the backgroundworker for marshalling updates to the UI.
Eventually the application will need to update a grid of devices via feeds from the defined agents, however for the purpose of this exercise simply updating a status bar on the UI will suffice. The section of the code which I believe is relevant to propogating the code to the form is contained in the OnDataReceived method.Below is a code excerpt from the protoype app which should put the above into appropriate context:
Code from the form:
[code]...
View 1 Replies
ADVERTISEMENT
May 10, 2012
We have a server application and a client application that communicates with each other using socket.
When the server application sends 2 messages about 16-31 ms apart, the 1st message is received by the client application with little delay (like 16-32 ms after it was sent). But the 2nd message is received by the client application a lot later (like 200 ms later) than when it was sent.
We already disabled Nagle algorithm (set NoDelay = True) in the socket in both the server and client application.
View 1 Replies
Feb 8, 2010
Can we pass parameters to a function using delegates
Private Sub UpdateLabel(byval text as string)
If Me.Label1.InvokeRequired Then
Me.Label1.Invoke(New MethodInvoker(AddressOf UpdateLabel))
Else
Label1.Text = text
[Code]...
View 2 Replies
Mar 17, 2010
I am using AddHandler to wire a function to a control's event that I dynamically create:
[Code]...
This code is generating a run-time exception stating: Unable to cast object of type 'MyEventHandlerDelegate' to type 'System.EventHandler' What am I not understanding about System.Delegate even though AddHandler takes as an argument of type "System.Delegate"? What Type does "EventHandler need to be to cast to a type that AddHandler can accept?
View 3 Replies
Jan 15, 2010
Just started VB programming this week and have found a wealth of information about what I'm trying to do. Problem is, some of it is more complete than others.Here's what I'm trying to do:In Form1 (my main form), I want to instantiate a class that contains a couple of properties (speed setpoint and position setpoint). When I click a button, I want to pass this data to Form2 and populate two textboxes on Form2 with the properties of this object. I want to manipulate the property values on Form2 and click an OK button which closes the dialog and returns the manipulated data, updating the property values of the object. Here's the algorithm I'm following:1) On Form1, instantiate the class2) On Form1's "Pass Data" button click event handler, instantiate a Form2 object and invoke the ShowDialog method, passing the object as a parameter.
3) On Form2, overload the ShowDialog method to accept the object as a parameter and modify the method so that it returns the manipulated class data.4) On Form2, in the ShowDialog method, populate the textboxes with the class data that was passed in.Here's where I get stuck. If I press the OK button on Form2 (DialogResult.OK), it returns me to Form1, but what hook do I have in Form1 to receive the manipulated class data that the ShowDialog method is returning?Here's an example of what I'm thinking about:
Code:
Public Class Form1
Dim clsController1 As New MotionController
[code].....
I'm sure it's probably a very elementary question, but every explanation I've found seems to be incomplete.
View 2 Replies
Aug 25, 2010
I am using an image button and on click of it i want to go to visited page.Now i am using - Response.Redirect(Request.UrlReferrer.ToString()),It is going to previous page, but when i am in a page of some user details where the link is looks like - users.aspx?userid=25 and i visit some other page and click back(image button) i want to see the same userdetail page. How to track that.
View 2 Replies
Sep 16, 2009
i am building this application for receiving data frm modem my application is consoled based, problem here is that its giving me an error in the line which is bold that invoke is not the member of mdm firstly i developed this with form, which has invoke method so i called it using me.invoke, now since i am at a console enviornment so it is not working..[code]
View 6 Replies
Jan 31, 2011
I want to create a custom class that has inside an array of another custom class (see my code below) but when the programm runs is crashes. Why? What is the right expression???? Plz help I'm a newbie in VB.net.....
Public Class ctrarray
Public nameclass As String
Public ctrlindex(glvar_spaces) As ctrlindexclass
End Class
[code]....
View 6 Replies
Aug 27, 2009
I am using VB2005 and trying to put an application together.What it needs to do is retrieve information from a binary file, possibly alter that information, and put it back into a new file.The file is a .wav file with data appened to the end. There is an additional section at the end of the .wav file which stores xml data.I have found that if I open this in a hex editor and make a 1:1 swap on any of the bytes that the application that the file is for can still read the XML.If I tried to add or remove characters from the XML then it would not read. I located a header byte and incremented it to resolve this.
This worked as an excellent bandage to do conversions where the data always needed to be changed to the same thing.What I have been asked to do is build logic that allows for different things to happen depending upon what data is contained within the file.The method that I am currently trying to impliment is:
Read through the file with a system.io.binaryreader
Searche for a bytestream that will signal data is coming
For example:
If System.IO.File.Exists("C: est estread.wav") Then
Dim findit() As Integer = New Integer() {&H3C, &H55, &H73, &H72, &H44, &H65, &H66, &H30, &H31, &H30}
Dim i As Integer[code].....
And then extract all the data till the end of element marker "<" It seemed like there should be a better way and I was looking for some insight. If I proceed with this method, I will have to read the file one time to gather the information and then a second time to write it all out with the header modified for length.This is my first experiene with working with binary files in this way.Also,I've been experiementing with building a string and slapping it back in at the end using the binarywriter.write(string) method.I noticed that it was putting in header characters before the string.These seem to change if I change the length of the string.At one point it was d0 07. Later it became e7 07. Does anyone know of a way to prevent this header from being inserted?
I tried a for each loop to grab all of the characters from the string, convert them to a byte array and deposit the byte array into the file, but the header remained the same. When I write the byte array generated from a system.io.binaryreader I do not get this header.
View 1 Replies
Mar 4, 2009
I've been pulling my hair out on this issue, and I can't find any topics that seem to help on this one.
I have a 3rd party unmanaged C++ DLL function which takes a string (char *) as one of its parameters then modifies that string internally.[code]...
View 5 Replies
Mar 4, 2009
I have a 3rd party unmanaged C++ DLL function which takes a string (char *) as one of its parameters then modifies that string internally.[code]...
Currently this code runs without exception, but desc shows 40 spaces when displayed to the messagebox. I've tried StringBuilders, but they don't seem to work. I've also tried changing the 2nd parameter to be ByRef but this causes a read/write memory exception.
View 5 Replies
Aug 9, 2009
I have the following [code]...
I thought make this would make my ada.myString have "working!" on the main appdomain, but it doesn't. I thought that by inhering from MarshalByRefObject any changes made on the 2nd appdomain would reflect also in the original one(I thought this would be just a proxy to the real object on the main appdomain!)?
View 2 Replies
Apr 13, 2011
What's the simplest way to pass a variable back and forth between 2 forms?Let's say I have form1 and form2. Form2 has textbox2 and button2. When button2 is pressed I need the text in textbox2 to display in textbox1 on form1.
View 4 Replies
Nov 20, 2009
I am using a RichTextBox control and a Socket Class. When I use the AppendText function in Form_load it get's added, but not in the event when text is received.
Code:
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
client.Connect(URL, PORT)
RichTextBox1.AppendText("Connecting...")
End Sub
Private Sub client_onConnect() Handles client.onConnect
[Code] .....
Just so you know, the MessageBox showing in Data is working perfectly.
View 10 Replies
Aug 29, 2011
Can I pass parameters back and forth between a Windows Service and .NET program? For ex: I want to pass a compressed/encrypted byte paramater to the Windows Service, who then decompress/decrypt it and return back the decompressed/decrypted bytes.
View 1 Replies
Aug 1, 2010
I am using the BeginConnect method of a socket to connect to a server which may or may not be on line I need to provide my users with a countdown timer which they can abort the attempted connection if they wish to The question is; how can I interrupt the Begin Connect method of an asyncronous connection
View 1 Replies
Jul 15, 2009
I wrote a server for a tcp/ip chat program using the system.net.sockets class. When I run the program and the client tries to connect to it, there's an error and it won't work. I am positive that the issue isn't with the client, as I have made a connection with the client before.
Imports System.Net
Imports System.Net.Sockets
Imports System.IO
Public Class Form1
Dim server As New TcpListener(IPAddress.Any, 60)
Dim client As New TcpClient
[Code] .....
View 16 Replies
Sep 28, 2011
i have a form that I need to do two separate functions, however about 95% of the code is the same it's just that last 5% so I don't want to create two forms. What I would like to do is when I click on a button to open the form pass it a variable or something so I can determine which of the two buttons were used to open the form.
Basically if Button1 is clicked do this if button2 was clicked do that...
View 1 Replies
Jun 15, 2009
Is there anyway you can send information back to the original creator of the program? Here is a quick example- I made a little program that gives you general information about your computer, when you click a button it sets the text box to specific information. One of the text boxes gives you the Version of your OS. I would like to know if there is a way to send the information in that text box back to me when someone clicks it and they are connected to the internet. FYI I would tell the person who clicks it before so that I am not stealing information, plus what is there to steal from a simple program I made.
View 2 Replies
Aug 16, 2010
I have such a bad habbit of cramming all my code into one form. But i dont know when i should write a class. or dont really understand how to return the information back to form1. when should i even use a class? for example i have some code here
[Code]...
View 10 Replies
Aug 10, 2010
I have an MVC application where all the data is tied together by VisitDate table in my database. The home page is a strongly typed view of type VisitDate, all it does is pull up some simple data. Now, here's where I'm having a problem. I need a link that passes the current model in the view back to a separate controller action so I can render a different page with different data. Here are my two controller actions. I'm going from News.aspx to FrontPage.aspx and hopefully passing SchoolVisit. [Code]
View 2 Replies
Jul 9, 2011
Trying to find some code to assist with accessing a web service. I am a newbie when it comes to web services and don't quite get the whole how to submit the request and then read the results. I know from searches that people request a copy of the WSDL file so I have attached (SystemManagementService.wsdl)
[Code]...
View 4 Replies
Feb 9, 2012
I am trying to add a back button on a popup. But I have having issues because I am getting a 403 error. I have also tried Request.UrlReferrer.ToString(). Simply right clicking and selected back works and the client does not want the tool bar with the stnard IE back button on the pop up.
[code...]
View 1 Replies
Mar 5, 2012
I am making a download manager in VB 2010. I need to be able to pass the download link from an HTML page to the VB Application. This is what i think i need to do in the HTML:
[Code]...
View 1 Replies
Jan 11, 2011
Just had to remove remove statics and use Delegates refering to class. i have got a little problem in one of my project.I need help to resolve it.My application Connect several FTP server with the same Class.I'm using TCPclient for few specifics Commands.The problem : All threads call the same TCPclient wich can't connect several server at once.I would like to create a New TCPclient for each thread.
[Code]...
View 8 Replies
May 18, 2010
Basically my program creates a text file based on whatever is contained in the 6 list boxes. What i need it to do is load the text it created back into the relevant list box. text file looks like...
Consignment Number-----Shippment Method------Expected Departure Date
CC33-1EA------------Express Air-----------18/05/2010
[Code]......
View 10 Replies
Aug 19, 2009
I've created a simple licensing system for a friend who has created visual basic programs which he sells at a few dollars each (they're speciality programs).The licensing system is coded in PHP (I'm a PHP coder), and the system requires the user to input their license key upon start up, if there is not already an activated key (which is created in a .txt doc)
View 2 Replies
Jun 13, 2010
How can I pass information from my textbox in my program to the username box on [URL] as well as password, and then execute log in?
View 2 Replies
May 8, 2012
I'm just starting out with vb and am working on a single form project.
Basically I'm trying to take information entered in a textbox on the main forum, Appear in a tab control at the bottom of the forum through the use of a button.
As far as I can tell, I need to code the onclick button portion of it but am unsure about how to pass the information to the specific label in the tab control.
View 1 Replies
Apr 25, 2012
I have a popup aspx page that receives data from a parent page gridview Edit click. There is a great deal of parsing of data from parent page to pop up as the data is being translated in pop up, then sent back to parent page to be reassembled in the original text block before update.
When the popup passes the data back or is canceled, the parent page gridview is still in Edit mode.I would like to pass the Cancel or Update button click from the popup to the parent page gridview so it can complete the update or cancel event without asking the user to click the corresponding command button link from the gridview edit mode, to Update or Cancel.
UPDATE: There is also a jquery UIBlocker on the Parent page to prevent the user from returning to the page until the PopUp page processing has been completed. Below is the critical code:
PARENT Page:
function parentFunc(a) {
// Unblocks on return from popup page.
$.unblockUI({});
[code]...
Had a problem with preventing the popup from reloading. So there is an if condition in the load event. A dynamic number of controls are built on the popup as literals. So the Page Init event and Page Load event fire on non Postback to rebuild the controls.
View 1 Replies