Passing Objects Between Forms?
Aug 11, 2010
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]......
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May 20, 2011
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?
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Jun 26, 2010
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...
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Jun 12, 2011
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.
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Aug 19, 2011
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.
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Jul 16, 2009
I have no idea where to begin. I've looked online but haven't been able to find anything.
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Aug 21, 2011
I 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.
[Code]...
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.
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Jan 31, 2012
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.
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Dec 28, 2009
Passing data between forms without any public methods or properties on the forms. everything but the "Controller" class, which I would like you furnish. I just changed the title from "Intermediate" to "Beginner" This solution is an example of the Observer Pattern. The "Controller" class is the "observed" class, which in this case means it publishes events.
' File Definitions.vb
Public Delegate Sub MessageDelegate(ByVal sender As Object, ByVal e As MessageEventArgs)
Public Class MessageEventArgs : Inherits EventArgs
Public Message As String
[CODE]...
The program should initially display Form1, and Form2. Clicking of the button on either form will modify the Title Text of both forms. I think that you will find the final end result to be pretty neat, as it works with any number of open forms not just two. I think asking for the Controller class is easier than asking for the code in the forms. My solution for Controller class has 7 lines of content, 9 lines if you include Class, EndClass. A minimal solution could achieved with only 4 lines of content, but it would a textbook example of bad programming.
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Jul 28, 2010
I use the code
Dim Selvk As New Selvkost2
Selvk.PassedText = TextBox29.Text
Selvk.Show()
[code]....
in my second form and the text passes. but I need to pass values from 20 textboxes. do I have to copy the code in my second form 20 times an declare passedtext2 and so on or is there an easier way to do this?
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Apr 22, 2010
This is my first Windows app to create since VB6. I've been in the world of ASP and ASP.NET for many years. However, now I have been asked to create a simple app that needs to be windows based.
[Code]...
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Feb 9, 2009
In VB.net how do you retrieve an value from a object in a different form.
eg:
' on frmMain
MsgBox ("Say ""Hello World"" Mr. " & frmOther.txtName.text)
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Dec 17, 2010
Example Form1 with data bound controls and a Public Variable Form1Var.Form2 with data bound controls and a Public Variable Form2Var DataTables are related Form2 Data is related to Form1 Data in a one-to-many.What I am trying to accomplish.When editing Form1 data there is a button to open Form2 if new data needs to be added. on closing Form2 I would like Form1 to remain at the state it was in before opening Form2. If I Change Visibility of Form1 when Form2 is opened upon Retun to Form1 Data is reloaded, if I minimise Form1 when Form2 is opened upon return to Form1 Public variables are reset to defaults.I have many Forms with many controls and buttons to do Lookups or additional add to related tables.
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Nov 12, 2009
I have a gridview on a form pulling user data. I have also created a basic login system where users login and their username/password is checked against a table in SQL Server 2005.The gridview is on Form 2 but i am having great difficulty in returning the records in the gridview for the user that is currently logged in.
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Aug 21, 2011
I'm getting a little fustrated, ive been trying to figure out how to allow my main from access to a sub form. what I'm initially aiming for is control of text and font color via a dialog on the main form and the results to appear on the second form, if that makes sense. Most of my knowlege resides around using VB.net for creating games and not progams. ill post the code so you guys might be able to get a better understanding of what im looking for as a result.
[Code]...
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Jul 23, 2009
My scenerio is a form with a button, when clicked opens a form dialog. The dialog allows the user to enter a text box. I want to read the value of the text box from the main form into a variable to be used with an SQL statement. The following code is used to create a new instance of the form dialog if one does not exist:-
[Code]...
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Nov 27, 2009
I seem to be running into an issue. This may seem like a noob question (which it really is, I only have experience in vb6 from years ago) but what Im trying to do is pass a variable from one form to another. Ive tried telling the first form to set the value of the variable on the second form like so frmsecond.variable = "value" but that does not work. Ive tried placing a public variable in a module to do it, but again, no luck. The only way seem to be able to get it to work is the second form setting the variable by reading the value from the first form like so [code]The problem I have with that code is what if for some reason the selected line gets changed as the form is loading or something to that nature. It doesnt seem very secure.
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Dec 29, 2010
If I have a large number of classes, each similar to the other in certain aspects (they all share a common base class, but each does things differently), and I need to create Windows forms for each to allow easy changing of their values through a GUI? Create one matching form for each object in VS' forms designer, Or Use code to create the forms dynamically at runtime.
#2 makes the most sense to me, because a lot of these objects will share very common features of the form, notably "Ok" and "Cancel" buttons. But one object might need to draw a textbox on the form while another might need to draw a combobox. Not to mention, if I want to put icons on the "Ok" and "Cancel" buttons, I'd have to do this for each copy of the form in designer, and that sounds like it could get out of hand quickly.But is drawing forms through code sane? VS' forms designer is pretty sophisticated and designed to make life easier. Am I wise to consider ignoring its functionality and diving into the trench warfare of forms design through code? Or are there examples of automating form creation based on an existing object's properties?
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Apr 22, 2012
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.
[Code]...
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Apr 10, 2009
I am trying to do a really simple function (atleast it was simple in 6.0)... what I want to do is have two forms. One with a textbox, and one with a button and a textbox (we'll call this one form2). When I add a value to form2 and click the button I want the text to appear in form1's textbox.
My code in form2 is...
' on event button1_click...
form1.textbox1.text = me.textbox1.text
("me" being form2)
Anyways, how to pass a value from one form to another.
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May 1, 2011
Im trying to pass a value of a date control from form1 to form2.on form 1.aspx.vb:
Public ReadOnly Property Property1() As Date
Get
Return StartDate.SelectedDate[code].....
Tried to assign the property to a string, it did not work either.
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May 10, 2010
I have 2 forms. Using Visual Basic.On Form 1 there is a populated combo box. This was done so by running a query through it and populating it with PUZ_ID values from a data set.On form two there is a tool strip and below is a search query.I need to be able to select the value i want in the combo box on form 1, and launch a button that opens form 2, which has loaded the data that i binded onto the form.Anyone have any ideas/code or need me to clear this up a bit more?So i need to run something through a query, or make something public or what?
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May 10, 2010
I have 2 forms. Using Visual Studio.
On Form 1 there is a populated combo box. This was done so by running a query through it and populating it with PUZ_ID values from a data set.
On form two there is a tool strip and below is a search query.
I need to be able to select the value i want in the combo box on form 1, and launch a button that opens form 2, which has loaded the data that i binded onto the form.
So i need to run something through a query, or make something public or what?
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May 20, 2011
I have two forms named are form1 and form2 (form1.h / form2.h)There are a textbox and a button on form1 and form2.When I clicked the button on form1, it must fill the textbox on form2 and when I clicked the button on form2, it must fill the textbox on form1 how can I do it,when I define #include "Form2.h" in form1.h AND #include "Form1.h" in form2.h, it gets me an error "error C2065: undeclared identifier.
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Jul 2, 2010
I designed a form simply holding a combo box, button & Datagrid, working well when executed from another erp application.Now i would like to get parameters from the application and pass on to the form. The parameter has to replace the value of Combobox value.
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May 27, 2009
I think I'm getting hung up on syntax here. I've got 2 forms and am trying to pass a textbox value from the 1st form to the 2nd. The textbox value is an unique ID #, so it's an integer value in the database. The ID displays in the textbox just fine on the 1st form. When I try to access the value of this ID textbox in code in the 2nd form, I see that the value is empty, or equal to "". But I see a valid ID # on the 1st form. Here's the code that shows me that the textbox equals "".
[Code]...
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Jun 4, 2012
solid rundown of how this process works using custom events &EventArgs, Im really having trouble wrapping my head around it
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Jan 28, 2010
I have a "Open File" menu on form1 that reads the user input data from the selected file, stores them into variables, passes on the var. to my form2 and loads up my form2 with the user input data. My code works But when I close my form2 and button click form1 to open form2, I still see the same input data I want all my text boxes to be blank.
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Jun 15, 2010
i have 2 forms -> form 1 and form 2
in form 1 -> 1 button
in form 2 -> 1 textbox and 1 button
when I click button in form 1, it will show the form 2..how can i pass the variable (data from textbox in form 2) into a variable in form 1 after clicking the button in form 2 ?
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May 17, 2012
I have a Form1, the user types a "Client ID" in a textbox if it's not a valid one, it opens a Form2 in which the user selects the correct "Client ID", once selected he presses an OK button. And there comes the porblem.. it opens a new Form1 with the Client ID that he selected from Form2, but I still have the first Form1 opened.
I have two Form1 opened...
I which to keep the original Form1, but with the value sent from Form2..
I'm using this code:
Code in Form1
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code].....
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