I have a wierd problem with threading in an ASP.NET application. For some reason, when I run the code in the request thread, everything works as expected. But when I run it in a separate thread, nothing happens.This is verified by calling the below handler with the three flags "on", "off" and "larma" respectively - in the two first cases everything works, but in the latter nothing happens.[code]
View 4 RepliesIm writing a small application that need to make up to 300 socket connections at the same time. However i'm pretty confused on how to approach this. My first theory is to have my main thread to manually fire up 300 new threads that each handle all that needs to be done. Another theory is to fire up lets say 10 threads that makes 30 async connections. My last theory is to have my mainthread work with all 300 async connections together with everything else. The question to this is what would be the most effective way to go to save resources and maintain speed.
View 1 RepliesI am working on a signout system I have a good start but am trying to solve a small problem.Signing out equipment I fill part of a form with student data from the dataset with Fillby, fill the other half with equipment data using Fillby1 I then save this combined data to my Access 2007 Database using a OleDb.OleDbConnection.
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figuring out which multithreading approach to utilize in my current work project. Since I've never written a multithreaded app in my life, this is all confusing and very overwhelming.I've been assigned to take over work on a control application for a piece of test equipment in my companies R&D lab. The program has to be able to send and receive serial communications with three different devices semi-concurrently. The original program was written in VB 6 (no multithreading) and I did plan on just modding it to work with the newer products that need to be tested until it posed a safety hazard when the UI locked up due to excessive serial communications during a test. This resulted in part of the tester hardware blowing up, so I decided to try rewriting the app in VB.Net as I'm more comfortable with it to begin with and because I thought multithreading might help solve this problem.
My plan was to send commands to the other pieces of equipment from the main app thread and spin the receiving ends off into their own threads so that the main thread wouldn't lock up when timing is critical. However, I've yet to come to terms with my options. To add to my problems, I need to display the received communications in separate rich text boxes as they're received while the data from one particular device needs to be parsed by the main program, but only the text that results from the most current test (I need the text box to contain all received data though).
So far, I've investigated delegates, handling the threads myself, and just began looking into BackgroundWorkers. I tried to use delegates earlier today, but couldn't figure out a way to update the text boxes. Would I need to use a call back function to do this since I can't do it in the body of the delegate function itself? The problem I see with handling threads myself is figuring out how to pass data back and forth between the thread and the rest of the program. BackgroundWorkers, as I said, I just started investigating so I'm not sure what to think about them yet.
i got inside
WebBrowser1_DocumentCompleted sub
the code below
WebBrowser1.Document.GetElementById("form").InvokeMember("click")
Call ProcessNextLine()
when it clicks this button it should load another page(Like log in)
Call ProcessNextLine()
takes next line from txt file (It's url) + navigate
but I want it to wait let the page load before calling "Call ProcessNextLine()" I tried System.Threading.Thread.Sleep not working?
Trying to get System.Threading.Timer to work!! I am converting a small form based application to run as a services, The app just runs an monitors a folder and then when it finds a file to does some work on it. Having changed the form.timer to threading.timmer - The timer stopps working after a while. Below is a simple test services - when you look in to the text file it stops after approx 130 entries
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I cant get System.Threading.Thread.Sleep to work..[code]
View 2 RepliesOK, I have this loop I want to perform which involves the serial port. Not to get too specific I'm actually sending data to an external device within a loop The loop involves a Start number, increments by a Step and ends when it gets to Stop This repeats until I click a STOP button.
View 15 RepliesI understand that there are several ways of Inserting, Updating and Deleting records in a database such as DataAdapters, DataSets, TableAdapters, SqlCommandBuilders, Parameterized SqlCommands, StoredProcedures, etc, etc,etc. According to David Sceppa Sprocs are the most preferred. Ok, I go with him on this one (who am I to challenge him anyway?).
My question is, apart from Sprocs, which of these options is the BEST for a large commercial database application and why, taking performance into account? What are the benefits and drawbacks of each option?
I am writing a program to assist Paramedic students in learning the Drugs that they have to know in order to pass their classes. I have created an Access database to hold all the information on these drugs, but not every student that will use this program will need to learn all the drugs contained within this database.
Right now I have 43 drugs in the database and still growing.
What I want to do is to present to the student the drugs and have them say "Y" or "N" as to whether its on their required list to learn. That way they only work on the ones that they need to.
I've two BGW with similar coding but different approach, My second BGW shows me "NOT RESPONDING" whenever i try move/click/focus to form while the BGW is running.
VB
RichTextBox2.AppendText("Some Text")
process2.ReportProgress(inc)
My.Computer.Network.DownloadFile(andpic, "pics/" & spliti(0) & nnum & ".png")
My.Computer.Network.UploadFile("pics/" & spliti(0) & nnum & ".png", "ftp://ftp.mywebsite.com/domains/mywebsite/public_html/Pics/" & spliti(0) & nnum & ".png", "users", "password")
WebBrowser1.Navigate("Mywebsite")
I've taken out number of things that i think is causing this error Are they the cause of "NOT RESPONDING" ?
To write a effecient Active Directory library to ease the work of technicals who are responsible to create access models into the domain controller's Active Directory. This library must allow the following:Basic operations: Add, Modify, Delete, List entries;An entry may either be an organizational unit, group or user (no further need required as of now);I thought about having a class which would represent the domain with which we want to work with.
public class Domain {
public Domain(string root) {
Root = root;
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I have a database with three tables:
stock
orders
order_details
Stock and Orders are self explanatory. Order_details is a lookup table, holding basically just the orderID, stockID and quantity for each item in the order. That's not very friendly for the user however, so what I want to show is a DataGridView with some elements from order_details, and some from stock, i.e.:
Part_Code, Item_Name, Description, Quantity, Price
I can create a database view for this easily enough, and bind it to a datagridview. It shows existing items in the order fine, but the problem is the view doesn't update when I add new elements to order_details in the dataset. It appears that it's bound to the main database, and so won't update until I save the record. That also has the problem that it's now much harder to update the database. A simple datagridview bound to order_details would make it easy for the user to enter quantities and for me to save the record, this one now needs a custom update statement.
In summary:
- I want to show data from two tables
- I want the datagridview editable (well, the quantity column anyway)
- I want the datagridview to update when I add entries in the dataset
What is the best/easiest way to do this? Is my current approach of a view in the database and custom update statements sensible? How can I get the datagridview to refresh whenever there's a change to the local dataset?
I recently started a project and needed to do some integration with LDAP via DirectoryServices. I've done this in other apps so I went into one of them to see how I did it -- why reinvent the wheel right? Well, while this wheel works, it was developed years ago and kinda smells (it's wooden, firmly attached to the previous vehicle, hard to repair and produces a potentially bumpy ride).So I thought to myself, this is the perfect time to refactor this puppy and make it more portable, reusable, reliable, easier to configure etc. Now that's fine and dandy, but then I started feeling a tad overwhelmed regarding to where to start. Should it be a separate library? How should it be configured? Should it use IoC? DI?
So my [admittedly subjective] question is this -- given a relatively small, but quite useful class like the one below, what is a good approach to refactoring it? What questions do you ask and how do you decide what to implement or not implement? Where do you draw the line regarding configuration flexibility? [Note: Please don't bash this code too much okay? It was written a long time ago and has functioned perfectly well baked into an in house application.]
Public Shared Function AuthenticateUser(ByVal id As String, ByVal password As String) As Boolean
Dim path As String = GetUserPath(id)
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I'm working on a system where there can be 2 level of users "Admin" or "Researcher".We have the requirement to allow the researcher to change fields for a record a record, but they want the original values to stay in the record and have an admin "accept" or "approve" the changes before the real record gets updated.Has anyone run into this scenario before? I'm trying to think of the best way to do this.
View 3 RepliesTrying to implement a recordset approach in VB.NET and have gotten to the point where things almost run. :)
Code:
Dim strSQL As String
Dim rsMaster As New ADODB.Recordset
strSQL = "select * " & "from tblDQ " & "order by xid, xcode, xDOS"
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I'm currently working on a system that requires monthly, quarterly and annual reports. I have no problem in generating/retrieving the data, my problem is the presentation. What is the best way to do it? I need the report to be:
View 3 RepliesWhat is the optimal approach to a WithEvents Collection - VB.NET?Have you any remarks on the code bellow (skipping the Nothing verifications)?The problem is when I obtain the LinkedListNode(Of Foo) in a For Each block I can set myNode.Value = something, and here is a handlers leak...
-Could I override the FooCollection's GetEnumerator in this case?
-No. :( cause NotInheritable Class LinkedListNode(Of T)
Class Foo
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I was wondering about what approach to take for writing a state machine or data crunching engine.As such, it wouldn't have any UI component. Since it must be able to talk to other GUI programs, should it be hosted in a DLL? I noticed that there were some State Machine templates for VB but I have no idea how to use them. If
any one could provide some pointers to documentation sample code,
any other approach on finding next word in a string. What im trying solve is this.
Lets say this is the whole paragraph.
Hello visual basic
Hello visual basic
Hello visual basic
Hello visual basic
Hello visual basic
Hello visual basic
now i search for the word basic.if i press the button find. the first "basic must highlighted, and then if i press again the button the next "basic" is the highlighted one and so on.I already finsih that scenario. What i've done is that first im going to search all the positions of the word and then store it in a array. Then after the array populated with different location of the word that is searching. that is the time i call all the indexes of the array one by one. But i don't want my approach because imagine i have 10000 words. and i search for a word or letter. Lets say the result is 5000 match. so it needs my array to be size in 5000. what a mess in memory.
I don't want to used the FinsString or Find function of VB i want some algorithm to do this. Anyone have a easy approach..
How to link my app to an Access database - there seems to be a number of approaches. I can add in my database via the Data Sources tab. Fine if I want to bind controls and view/edit data. But is this the best approach for queries that return an answer that is a different shape to the original table? Alternatively I can connect to the database directly (connection string, etc) and run sql queries. What are advantages/disadvantages of each approach? In terms of flexibility, is the second approach best? Also, does the second approach require the database to be added via the Data Sources tab?
View 4 RepliesI'm using VB.NET but this question applies to any OO language - Java, C# etc. I've tagged the question with Java and C# but will remove if not considered appropriate. I have an entity class ClassAAA that contains a reference to ClassBBB as one of it's attributes:
Public Class ClassAAA
Private Property _blah As ClassBBB = Nothing
Private Property _somethingElse As String
Private Property _anotherthing As String
' Make it private so cannot instantiate class without supplying ClassBBB '
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I could make the ClassBBB reference public (or supply a public getter method) but that would expose the inner workings of ClassAAA. What I'm thinking of doing is making the ClassBBB reference Friend so that it is only visible in the assembly i.e. a data layer and is not visible to client projects. But this stills feel like I'm exposing the inner workings of the class.
DB/Reporting :: General approach to a db project
View 2 RepliesWhich is the recommended approach for copying elements from one control to another? Currently I am using something like this:
For Each a As Control In control.Controls
Controls.Add(a)
Next
Should I stick to it, or should I change to use the ControlCollection.CopyTo method instead?
I want to know what's the right way to work with objects that belong to a category.I'm building an applications with the following layers:Base data access Data access Business logic + Factories Presentation.I want to pass only objects to the presentation layer and back.I have objects (Employees), that belong to a certain category (EmployeeCat). I was wondering if I should have just an EmployeeCatID property in my Employee class/object, or an EmployeeCat property that contains a complete category object.If I want to fill a GridView with a list of employee objects as datasource, and I used just an ID in my Employee objects, then I will have some work at the presentation level to display the category names, so I think. On the other hand, if the list of employees contains plain category objects... I'm not sure what will happen.
View 2 RepliesI am often asked to create a very simple database front-end for friends or family, and the structure of the database (and application) is usually very similar.Right now I am always creating a class that handles all database interactions with some shared functions. For example, there's a function to run a general query and return a table, a function to save/load various items (depending on the application of course). The point is: the code is nearly always the same except for some slight variations.
View 5 RepliesHere at my company we have an Access application that allows users to create documents based on invoices that are in Great Plains. Documents such as invoices, packing lists, export documentation, etc., etc.This application is very old and very hard to maintain so we're doing a rewrite and I've chosen this project to be my first Visual Basic .NET project.
View 5 RepliesWhat is the recommended way in VS.NET to have a global application handler object? Something that can load/verify/return user folders, settings, application specfic settings, manage the unhandled exceptions, etc. I would have a class that has most of the code, then subclass it for each application.
I can create one if I start as a module instead of a form. But then I lose some options such as NetworkAvailabilityChanged, etc. I define a "Public" object from within a form (I don't think so and don't feel this would be the right approach.)?can I "attach" an object to an existing global object store (such as "My."), etc.?
Once created, any object in my application should be able to reference methods/properties of this application object to get default folders, user values, etc. as necessary.
I've got a method which takes some parameters and generates some XML to be sent to an [archaic] web service.
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I have a question on the best way to store model data for my app. My app will basically be drawing a bunch of elements (lines) connected to a node at each end. Im trying to decide how im going to store my node data (as well as element data). The node data im trying to store will consist of the node XYZ coordinates and some other info about the node. The element data will consist of the node numbers at each end plus additional info about the element. There a number of ways i've been thinking i can do this. They are:
1) Store my node/element data as a Dictionary object, where the key represents the node/element, and the value would be an array of the information i want to store.
2) Create a "Node" structure and an "Element" structure to store the info i want. Im a bit worried here as my model could potentially have thousands of nodes and elements.
3) Create a "Node" datatable and an "Element" datatable, and store my info in those instead. I can see some advantages in this in regards to displaying information to the user in datagridview etc. But then again i can easily pull the required data from a method i mentioned above, and generate the datatable when required.
Not quite sure what the best approach is. Either way i do it, i will be serializing whatever object i use to save the data to disk.