How do you reference a variable in another Class?
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
TextBox1.Text = "Class1_Text" ' Would like to replace w/correct code
End Sub
End Class
Public Class Class1
Public Class1_Text As String = "Class1 Text"
End Class
I can reference the Form1 data in Class1 but not vice-verse.
So Im iterating through the properties of a class. For each property Im iterating through a datatable until I find a column name with the same name as the property.
No worries so far, here's the isse: Once I've found a match I want to set the class's property to the value in the datatable but I'm having difficulty referencing the property as it has to be done through a variable.
Code:
Dim per As New Person
Dim t As Type = per.GetType
For Each p As PropertyInfo In t.GetProperties
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I have a question about assigning variables values based on values stored inside an sql database. I have the connection part down, but here is my basic set-up. I have a table with the values {username, password, isAdmin}, where username and password are strings and "isAdmin" is a bit variable. I am able to read in the username and password entered by the user and match it to the database fine, however I would like to also read in the "isAdmin" and set it to a local Boolean variable that will then direct the user to the proper form.
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I wrote the following two functions in a class to take a gpib reading and also take a measurement from an LCR meter.
HTML
Public Function gpibRead(ByVal Channel As Integer, ByVal buffer As Integer) As String
Dim readingBufferA1 As String
Select Case Channel
Case 1
readingBufferA1 = gpibLCRA1.ReadString(buffer)
Return readingBuff
[Code] .....
When on the main form I call the funtion takeMeasurement(1) how can I get the LCR readings back. If I try and use readingBufferA1 on the mainform it doesn't recognize that as a variable. I know that it is taking the reading and storing the correct numbers because I am monitoring on NI Spy.
how to create a class yet, and I think I need to learn how.I am wanting to shorten my code in a form, thinking of creating several classes to do so.Lets use a Listview as a reference if you dont mind.Say there is a listview, you have a numeral amount of if statments to fill by. Is there a way to create a class(is this the way to go) so that you can open the class to modify that specific block of code? Example of questionYou have multiple items you need to add for each if statement. Animal as a group Dog as an item 14 years as a sub item Cat as an item 11 years as a sub itemIs this the way to go, if so how do you create a class and call it from a form?Davids Learning
View 4 RepliesI am building application that will be hosted as a web service. This app takes an employeeID and returns an employee object that contains lots of info regarding the employee. (name, status, full-time/part-time, etc)I want the two existing apps we have (and more to come) to be able to call a method that the web service will have and return the employee object. (also at time this web service that returns the object may have new fields added to it - Pay rate, etc)How would I go about creating a new object from this web service reference in the existing applications.Would I decalre it like Dim Employee as new emp_webservice.employee? And then be able to use this object within the app? Or would the better practice be to also included the same class files? It seems like this would not be the way to go, since if I make a change to that class I then have to make it in all places.
View 1 RepliesI have several sets of similar objects (labels, progress bars) on a form in Visual Basic 2010 on Windows. In my code, I have collections that contain data, which needs to be pushed into the value/text property of each.
I would like to get a solution similar to PHP in that I can assign values somewhat like:
For ID as Integer from 0 to count(collectionExample)
lblExample{ID}.Text=collectionExample(variableID)
...and as such to loop through so each of the different lblExample's were updated to their corresponding value.
The issue I have come to is that I cannot seem to reference an object on the form using a variable. I have also tried using something like
CallByName("lblExample" + variableID, "Text", CallType.Set, exampleCollection(variableID))... however I still can't combine the string and variable to reference the object.
Any solutions on referring to objects in VB2010 by combining a string prefix and a variable string identifier, similar to PHP's $variable{$variable} approach?
Edit: Windows Platform
How can I implement a tree structure (Octree) in Visual Basic.
that is to declare a class containing array of objects of same class type - like
Class Node
{
dim ....
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when using variables in object names.I have a Public class which is called "Tank".In that class, there is a public property called "direction" of an integer type.I keep getting the error:
"Tank is a type and cannot be used as an expression"What I'm doing wrong here ?
Public Class mainroutines()
Create Instances of tank
Private Tank1 As New Tank()[code]....
I have created an SNMP class. And then I want to test this class, so I create a program which imports this class ...
Imports SNMPClass
Module Module1
End Module
Public Class SimpleSNMP
Public Sub Main(ByVal argv As String())
[Code] .....
I got an error in this line
Dim conn As New SNMP()
Which says "SNMPClass.SNMP is not accessible in this context because it is friend"..
I am using Visual Studio 2008
I have a problem to solve and not quite sure if the way I think is correct.
I have a main form class MainForm the class has got: a variable call Value and a label called LabelValue
Now I would like to automatically update LabelValue every time the Value changes his value
I'm working on a legacy vb.net application that does most of its work using inline code ( Within that script I need to access functions from a third party .net dll. The dll(s) themself are stored in the GAC. Before I started the page looked something like the following
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Referencing an object (class) within a thread fails
I have an object ("a vb class") that needs to run on a separate thread and communicate with the U/I.
Even using sample code, I cannot get the object to run within a thread. I demonstrate this problem with two examples. The first calls a function within the form and it works perfectly. The second creates an object and performs the same calls, but fails.
example #1 [working] (Called within a form)
Private Delegate Sub FuctionToBeRunInThreadDelegate
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
[Code]....
SUMMARY: When the thread creates the object, it appears that the object is not actually running inside of a thread or else form.InvokeRequired would be true. I have other more complex examples where this is strongly verified and evidenced, but I provided these two as a very simple demonstration of my problem.How can I have a thread "own" a series of individual objects so that the objects are run asynchronously and can independently report back to the U/I?
I have class file class1.vb with 3 classes class1 , class2, class3. a class file class10.vb with class10 class11 class13
I declared class 1 public and declared a public shared new instance of class11 in class1 at the top
All classes in class1.vb can use this shared instance, but a form4.vb doesnt see the shared class1.(new instance of class11)
I have a collection class, say ITEMS, that inherits a Dictionary (of String, SINGLEITEM). From the SINGLEITEM class, I would like to reference a property in the parent ITEMS class, what is the best way to do this? For example, say the ITEMS class has an IsDirty property and I would like to set that if ANY of the contained SINGLEITEM objects is modified, what's the best way to go about doing this?
I know I could add a reference to the collection class in each SINGLEITEM class (since I override the ADD method, I could make this assignment), but this seems like overkill.
Say I have a Framework 4.0 project that is referencing a class library targeting 3.5. The project will simply not build. It won't give me any valid error message it will just act as though the reference does not exist.
Projects that were working like this in Visual Studio 2008 are no longer working in 2010. Took me forever to figure out what there error is. If I remove the project reference and add it back the intellisense lights up and you can tell a variable referenced in the class library is found. But as soon as you build the project everything is lost. My using statements get underlined, references to the variable all turn grey and project fails to build saying the class cannot be found. Once I make the class library 4.0 as well everything builds. I get the same issue between 4.0 client profile and 4.0 as well.
i had a class called Tag with a structure like:
public class Tag
private _members
public properties
public shared database_methods
end class
this class was tailored for mysql database. i'm currently adding access 2007 support so i split tag into tag and tagdata with structures like:
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Create a class named Service. Inside the Service class, declare a class variable named Started. The datatype of this variable is Boolean.Public Class Service Dim started as Boolean End Class Create a class named Server. Inside the Server class, declare a dynamic array that can contain elements of the type Service.(Note: For convenience, both the array and the variable Started can be accessible from a client program that creates an instance of Server and Service respectively)
Create a constructor for the Service class. When the constructor is executed, it will set the value of the class variable Started to True. Create two new classes: WebServer and DatabaseEngine. Both of these classes inherit from the class Service. Inside the Service class, declare a Sub procedure (method) named Terminate. This method should display the following text Service stopping in a message box when executed.This method can be overridden in classes that inherit from Service class.
Inside both the WebServer and DatabaseEngine class, override the method Terminate inherited from their base class Service. Both methods should first call the base class Terminate method. The messages Web server stopping and Database engine stopping should also be displayed in a message box when the Terminate method for the WebServer and DatabaseEngine are called respectively. These messages should only be displayed if the Started variable inherited from their base class is not equal to False.
Inside the Server class, declare a method named Shutdown. This method does not return any value. When executed, it will call the Terminate method for each of the Service instances (if any) in the arrServices
array. You should call the Terminate method within a For Each loop that loops through the elements of the arrServices array.
In the Sub Main method, create an instance of the class Server. Set the size of the arrServices array in
your Server instance to contain 2 elements. Create first a WebServer instance and then a DatabaseEngine
instance into this array. Call the Shutdown method from your Server instance.
I want to created a nested class that can only be visible to and instantiated from the parent class.But I also want to be able to use an instance of the nested class through a public variable of the parent class.I tried making the nested class private, or making the nested class' constructor private, but it won't compile.Is it possible to do this in .NET?
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I have 2 Forms in a VS 2010 Project. Form1 is the Startup Form and can, with intellisense see Form2, but NOT the Controls on Form2.
Form2 can with intellisnse, see Form1 AND the Controls on Form1.
Why can't Form1 see the Controls on Form2? I've not seen this issue before in VS or VB6.
The error message is :-
Reference to a non-shared member requires an object reference.
The Controls on Form2 have the Property of Friend.
I have 2 forms in my project. Form1 does all the grunt work and Form2 is a setup form.
In a module I have placed this
Public myForm2 As New Form2
In Form1 I have this in a routine
For Y = 0 To myForm2.lstCallWatch.Items.Count - 1
The listbox has 12 items in it but the items count is ALWAYS 0
What am I doing wrong to read the number of items in the Listbox?
example:textbox1.text = "frmHelp"...is it possible to go to the form (.show) by simply using the form's name, also how?
View 2 RepliesI have procedure (Import) that calls a for a new instance of frmImportData. I also have a class name clsBatch that has a data table property called prpParametersTable.For some reason, I get an error (indicated below with ERROR>>>) when trying to assign prpParameterTable to cv_dtImport2. The error states "Object reference not set to an instance of an object.". Why does this error not happen when I assign dtBP to cv_dtImport1? Both cv_dtImport1 and cv_dtImport2 are equal to Nothing and in my Import procedure dtBP = prpParametersTable.
Public Sub Import(ByVal clsB As clsBatch)
Try
Me.cv_clsB = clsB
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I have three class files, accounts.vb and transactions.vb in addition to my form.vb. I am unable to retrieve a member variable from on class from inside the other. When the combobox index changes, the program loads the correct account (checking or saving) from two different sequential files. I don't think I have the calcBalance procedure in the correct class file. And that is what I am having trouble with. Accessing it to display it. [Code]
View 1 RepliesWhat i'm trying to do:
I've got a library which includes a class:
Class Human
End Class
and another class which refers to the human class
Class ASD
Private somevar as new Human
End Class
Ok now i've got a problem, i wish to rename my class Human, to Man. i've got to change Human to Man 2 times, which is OK but the problem is that in the real case, its not just 2 times, its like 500 times or more.
Well its something like a PHP on Javascript.
the following shows the solution of what i'm trying to do, but its in another language PHP/Javascript:
note: in php $ sign declares a variable, echo writes the variable out
CODE:
Is there anyway to do that with VB?
This is bugging me. I have a "main" form named frmMain with a DataGridView object named objDataGrid.When a user double clicks on a row or clicks another button, I hide the main form, open a new form and want to reference the values in the row selected by the user but I keep getting an error when I try to access some, but not all, of the datagridview's properties.
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Usually I would just do Form.Control.Property but that doesn't work.It just seems overly complicated with public classes, etc.Is there a more simpler way to do this? I'm ready to throw in the towel and just use a global variable at this point.I have the form containing the control I want to reference, frmGenerate which has a textbox called txtCustomerNo.From this form through a button's click event I want to show another form, frmCustomers, and have that form reference the value in txtCustomerNo.
frmCustomers.ShowDialog()
I have the following code:
Option Explicit On
Imports System.DirectoryServices
Imports System.IO
[code].....
I have a form in VB with many (over 100 - fields, labels, the form itself etc...) items on. I wondered if there was a way of refering to all the items on the form without having to list them all individually in the Handles keyword, which is extremely long winded! I want to carry out the same action wherever the user clicks on the form. At present I have the following
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I designed 7 class libraries for 1 project.The project references all 7 libraries.3 of the 7 libraries make references to the other 4 libraries.I thought of just duplicating the code that's referenced in the other 4 libraries, but thats a lot of code.
Example:
PrjctA makes reference to LibA, LibB, LibC, & LibD.If LibA references LibB & LibC also will this fail?