I have the following problem. This is a simple example of some classes I have (each have dependencies on other classes).
public Class1()
{
public Class1(Class2 class2)[code].....
The problem I have is that the assert is always null, even though class1 has been initalized. One condition I do have is that I only want there to be one instance of each class created.
I have this code to get the default constructor:
Public Function f(ByVal t As System.Type) As Object
Return t.GetConstructor(New System.Type() {}).Invoke(New Object() {})
End Function
I need to pass values to the Constructor as
Public Function f(ByVal t As System.Type) As Object
Return t.GetConstructor(New System.Type() {someInteger,someString,etc.etc}).Invoke(New Object() {})
End Function
Also I have 3 classes of Type T, with all having different parametric constructor. It's important for me to have it generic as the Classes of type T might increase in future with less or more parameters.
I am making use of a 3rd party dll and am encountering some strange behavior in VB, which doesn't occur in C# Perhaps someone can explain what is going on. Anyhow, I am making use of a method in this 3rd party library which accepts an array parameter ByRef. The end result is the variable should remain null after the method call, but it is returning initialized for some reason.
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I'm translating a document management application from vb6. I want to program with good habits and technique, so I'm asking for your opinion really rather than just a solution.I have a decent understanding of OOP, but I'm not very experienced in VB at all. What I'm doing now is trying to figure out the best way to pass objects between forms.For example, in my initialization form, I have an object that stores a group of database connections. I need to pass this object around because reconnecting takes a significant amount of time. There are other objects such as user info and permissions.
Public Class Form 1
Dim DB = New DBobject
Public Sub Form1_Load
[code]......
I have an ASP application, which calls an HTTP WCF service, which calls a TCP WCF service (all on different servers). I'm ultimately trying to pass one class object between the three.I've discovered that I can't do this directly in the HTTP WCF, even though my class object is defined identically in BOTH WCFs. Like this:
Public Function CallOtherFunction(ByVal ThisClass as MyClass)
Dim RetVal as Boolean
RetVal = CallMyOtherWCFFunction(ThisClass)
End Function
Instead I have to:
Public Function CallOtherFunction(ByVal ThisClass as MyClass)
Dim RetVal as Boolean
Dim MyOutgoingClass as MyOtherWCF.MyClass
[code]....
My objects are rather large, to say they have a lot of properties. Any way to not have to declare a new variable in my calling function?
I always thought I understood how this works...but lately I have started really using interfaces and now things arent doing what I am expecting.
using entity framework, I have a service for each object that is responsible for interacting with the database and such....on my one service I am passing the collection of objects to my service as an icollection(of contactinfo) before I pass the object, the changetraker has the right states. however in my method, this is not the case and all states are set to unmodified.
Private Sub SaveExecute(ByVal param As Object)
Dim srv As Services.ContactInfoService = GetService(Of Services.IContactInfoService)()
[Code]....
As I said above the Me.contacInfoCollection has the right changetracking states. But Once its passed to the srv.savechanges it reverts to unmodified. I am sure its something silly I am missing...the whole EF thing can be confusing to me...
I have the following code in Class B
FolderList.add(FolderCategory)
when i do a count it display a list of 25 items in the folderlist.Now i have a main class when i tried to use the following method
Dim MainClass as New ClassB
Console.writeline(MainClass.FolderList.count()) the value reflects as 0 items meaning is empty.i need to retrieve the arraylist from Class B using the MainClass to retrieve those items inside the arraylist.
I have no idea where to begin. I've looked online but haven't been able to find anything.
View 1 RepliesI was wondering if someone could tell me if this is "bad practice" or is a perfectly acceptable way to pass an object to another form.I've cut out a lot of the code to summarise what im asking.
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Dim myRetrievedObject as myObject = Module1.returnSavedObject()Is this a acceptable way of passing an object between forms or is it a completely bad idea?Ideally i would like to be able to "add" further objects to the initially created object in Form1 but then on reloading of Form1 , retrieve the new version of myObject with the newly added objects within the myObject class.My initial thinking is this creates an almost session like state for the initial object. So you can use the same object over all 3 forms or more and just simply add to it like a shopping cart type of functionality.
I have adopted a technique where I pass existing objects to forms so that they can display the object's content and allow the user to alter it if necessary. The form is not bound to the object, so when it comes time to act, the form sweeps up the content of its controls and puts them into the object. The object is then validated and any issues reported to the user. If the object is valid, it may be handed back to the caller so the caller can refresh a view/list/etc.
So far, so good. However, if the form's content, or lack of, creates an invalid object and the user does not correct it, maybe cancelling the form, there's a chance the form will hand an invalid object back to the caller. This is not good.
Essentially I'm looking for an elegant and efficient way of either leaving the object as it was or rolling back if the user cancels the form/action.
I have considered a range of techniques, each with many pros and cons. I'm keen to consider some other views.
I have an abstract class which requires a delegate to function. I pass the delegate into the constructor. Now that I have a non default constructor I need to call the abstract class's constructors from the concrete class which means that I need to use MyBase.New(...). I have included a quick example below.
Public MustInherit Class BaseClass
Public Delegate Sub WorkMethod()
Private _Work As WorkMethod
[code]....
I have tried to do this but I keep getting the following error: "Implicit reference to object under construction is not valid when calling another constructor".Can I not do what I am trying to do above? I initially had the delegate setup in its own setter method. But then I am creating a deceptive API because it does require a point to a method to work properly.
what's the rationale behind this limitation: Constructor call is valid only as the first statement in an instance constructor i want to pass an argument to my constructor which validates this argument and calls mybase.new according to this argument but it doesn't let me
example:
Public Class prob
Inherits System.ApplicationException
Public Sub New(ByVal problem As String, ByRef inner_exception As Exception)
[code]....
Base class has one field to hold numeric balance value. With 2 methods that accept arguments for adding and subtracting the new input calculating new balance. Sub class has four fields dates, transaction, memo and amount.I have a deposit form, and withdraw form. Each time one transaction is entered it creates an object with sub class fields, then adds to the account collection. My problem is not understanding how to call the deposit/withdraw method and pass the current transaction amount back to the base class to alculate the new balance. Does anyone have any links to information/tutorials on how to perform something like this? As you can see with my code I have tried various different approaches without any success.
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make objects from the ToolBox using code instead of changing existing objects invisible then visible later?
View 7 RepliesI am getting this error, Not sure why it is happening "Error The SqlParameterCollection only accepts non-null SqlParameter type objects, not Int32 objects."I have tried with all sorts of possibilties, now try to enter default data as dummy data,
Using connection As New SqlConnection
connection.ConnectionString = ConfigurationManager.ConnectionStrings("DentalDeviceConnectionString").ConnectionString
connection.Open()[code].....
I have a program like this.
Module Module1
Public Class Mstr
Public Property Prop1 As String
Public Property Prop2 As String[code]....
But it is not working as I expect it to. You can see it from.The DtlsB properties of all three DtlsA objects are having values from last iteration.
I want to let the user input objects to a richtextbox 1 object on each line, and somehow use Random.Next to select pseudorandomly a few objects, the number 'few' inputted in a textbox.
View 9 RepliesPrivate Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Using conn As New SqlConnection("Database=Clinic_Management_System;Data Source=.SQLExpress;Integrated Security=True;AttachDBFilename=|DataDirectory|Clinic Management System.mdf")
Dim cmdRecord As SqlCommand
[code]....
I have a user control that inherits the FW ListView and I need to dispose of two objects when the form's disposing of it's objects. Here's what I've concluded already, am I on the right track?
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long story short, I have created a ListView type control, using UserControls for the parent control and the ListViewItems. Most the of the control is written and works fine, right up to the point where I tried to replicate the 'Control.SelectedItems(0).Index' property and the 'SelectedIndexChanged' event.
Each child object knows its index value, and could pass this value via the SelectedIndexChanged event (assuming this is how it works in a normal ListView control -- user clicks on an item, and that item fires an event updating the selected index value in the parent object).
How does the child object raise an event in the parent object? I have a feeling this could be done with Delegates, but I'm still learning about their usage.
i am getting this error message while trying to Connect to a Database from the Server Explorer:"Unable to add data connection. The IVsDataConnectionDialog could not be initialized" i am using VS2008 mainly and i have also a VS2005 instalation that works just fine.i have tried to uninstall/repair for 3 time now.
View 7 RepliesI've looked at a lot of posts on different forums where others have received the same error. Most say they were not referencing the connectionstring from the web.config file correctly, or they were trying to open the connection before setting the connectionstring. Well, if that were the case for me, then how does it work on two different systems, but not on the third? It works on my development PC and on the development server, but not in the production environment. The difference is the web and DB server are separate physical servers in my production environment and on a single server for development. My setup, error message and code will be listed below.
I can simulate the error on my PC if I rename the connection string in either section of the web.config file (appsettings, connectionstrings) to something else. You will see how I have tested both below.
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I have a web application that works perfectly on my local machine but not once Ive uploaded to the hosting server I get:
Server Error in '/' Application.
The ConnectionString property has not been initialized.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidOperationException: The ConnectionString property has not been initialized......
I have a web application that works perfectly on my local machine but not once Ive uploaded to the hosting server i get:Server Error in '/' Application.The ConnectionString property has not been initialized.Description: An unhandled exception occurred during the execution of the current web request.review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidOperationException: The ConnectionString property has not been initialized.Source Error:Line 423:Dim conn As New SqlConnection(connstring)
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Public Class MyClass
Property Form as Form
Public Sub Mysub1
[code].....
I keep getting an error that the ConnectionString is not initialized.
Here is my
'* Configure data adaptor and fill data set
sqlDABC.SelectCommand = sqlCmd
sqlDABC.Fill(dsBC, "Supplier")
i have used the autofill method of datagridview, but while i am preparing the system, i have to use different connection string for one datagridview and i think that hardcoding the fill method is the best solution. while at it i have the following as my code:
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i get error " the connection string property has not been initialized" while inserting. am using MS access as database.
View 4 RepliesI have 2 datetimepickers. I want to run a select statement between startdate and enddate. When I run the project. I get the error: "The Connection String property has not been initialized." [code]
View 5 Repliesgetting the following error Unable to cast object of type 'System.Object[]' to type 'OrderService.webdirect_WebLinesRow[]'. On the line
webdirect(web_companyID, web_locationCode, web_customerNumber, web_orderNumber, web_orderReference, web_orderDate, webLinesArray.ToArray(), o_Company, o_LocationCode, o_CustomerNumber, o_OrderNumber, o_OrderStatus, o_OrdDescrip, webRespArray)
I created the webLinesArray.ToArray() array as such
Dim webLinesArray As New ArrayList()
Am I missing an additional cast or something ?