Such as:
mylist.FindAll(Function(item) item.property = variable)
The reason I ask is if I use syntax like this, I tend to get a string to whatevever conversion error, which makes me think "variable" is being treated literally as a string.
In C# I have been performing a FindAll in a generic list as follows:List<group.category> tlist = list.FindAll(p => p.parid == titem.catid);Two questions, is this the appropriate way of performing such a thing and how do I convert this to VB.Net
View 1 RepliesI pass this class i created a variable by reference and i want that reference to be assigned to m_Text so that when i change m_Text it changes the TextValue variable i passed. Example:
Dim test2 as String = "ok"
Dim test as New GeneTextBox(test2)
'then some one changes the text in the GeneTextBox and i want it to change the test2 string...
Public Class GeneTextBox
Inherits Windows.Forms.TextBox
Private m_Text As String
Public Sub New(ByRef TextValue As String)
[code]....
I have the following code passing a dataView variable to a function and I am getting the following warning:"Variable 'cl' is passed by reference before it has been assigned a value. A null reference exception could result at runtime."
Function Editclass()
Dim cl As DataView
Bindclass (SqlConnection2, cl)
[code].....
The code below works for the class that I hard coded "XCCustomers" in my RetrieveIDandName method where I use CType. However, I would like to be able to pass in various classes and property names to get the integer and string LIST returned. For example, in my code below, I would like to also pass in "XCEmployees" to my RetrieveIDandName method. I feel so close... I was hoping someone knew how to use CType where I can pass in the class name as a string variable.
Note, all the other examples I have seen and tried fail because we are using Option Strict On which disallows late binding. That is why I need to use CType.I also studied the "Activator.CreateInstance" code examples to try to get the class reference instance by string name but I was unable to get CType to work with that.When I use obj.GetType.Name or obj.GetType.FullName in place of the "XCCustomers" in CType(obj, XCCustomers)(i)I get the error "Type 'obj.GetType.Name' is not defined" or "Type 'obj.GetType.FullName' is not defined"
'+++++++++++++++++++++++++++++++
Imports DataLaasXC.Business
Imports DataLaasXC.Utilities
[code]....
I'm trying to get specific elements of a listOf structure with the function findAll plus a lambda function, and then sort that result and keep that sorting of those elements saved in the list. The structure of the listOf has an id and an age, so what I want is get all the items with id=0 and then sort the ages of that result, keeping that modification in the variable.
View 1 RepliesI am working on a program for a client and will need a feature to search for strings from an array without case sensitivity. This currently works, but it is case sensitive. I commented out the code for readability.
' Declare array for goldSmithingExpertise and add items.
Dim goldsmithingExpertise() As String = {"Alluring Earrings", "Alluring Ring", "Alluring Belt", "Howling Staff", "Dawn Ring", _
"Melancholy Earrings", "Melancholy Belt", "Melancholy Ring", "Jubilant Ring", "Jubilant Earrings", _
[code]....
I think (?) this is about object design, and perhaps about structural and/or creational patterns. But a bit hard to say when I only know a couple of patterns yet.[code]But... what if we INSTEAD want each Product instance only to (in some way) refer to one instance of a specific list of Components. So we wan't to save the products list to one file, and the components list to another file. Then would I build the objects the same way, or different? So let's then say we have now Class B as below. [code]
1. Will not need to update each component variable of the products list when the components list changes.
2. If the Product object shall be shown in a DataGridView, for editing properties, it seems easier to implement the selection of the component property.
Is this wrong approach? Is it suitable in some cases, and if so, when? Are there other solutions I perhaps am not aware of that would be appropriate? Is this about structural design patterns? and if so, can the alternatives above be catagorized to some pattern type? I don't really know exactly what I'm looking for.. But I think probably I'm looking to understand whether the object design will be determined by the way the objects are saved.. And if i shall save the objects by serializing to file, vs saving to a database, would I create the business objects differently?
I am importing data from an Excel spreadsheet into an array. I want to search the array to find the location of each "cell" with text that contains a certain string (e.g. "MyTestString"). So far the best I can do is loop through each element and test it using CStr, but the code takes too long to execute (please assume all variables are properly declared):
[Code]...
(1) Is there a better way than looping through each element, such as a built-in function or a lambda that will return an array containing *the location of* all string matches?
(2) Would it be faster to convert the Object array to a String array rather than using CStr on each element? If so, what is the fastest way to convert a 2-dimensional Object array to a String array?
I've considered using Excel's Find function instead, but would prefer to limit the number of Interop calls to Excel.
I am upgrading a very large project from VB6 to VS2008. I have several forms with dozens of combo boxes on each form. I use the same combo box names for each form and want to fill them from a module with different items depending upon the calling form. In VB6, I dimensioned a public variable - FormName as object and called Set FormName = frmMyForm1 on Form Load. In a module, I was able to write the following code:
With FormName
.combobox1.additem("item")
.combobox2.additem("item"
End With
I cannot make this work in VB.Net. When the form loads I call FormName = Me. If I dimension Friend FormName as Object, I get the error message that Public member combobox1 on type MyForm1 not found. If you are attempting to access members on a late-bound object make sure it is declared public". If I dimension Friend FormName as Form, I get an error that says "combobox1 is not a member of System.Windows.Forms.Form".
I have tried both CType and DirectCast to convert the form variable from Object to Form with no success. I also tried creating a public array and storing each form name in it.
I am working on a little program (game) is called Pig latin. I created a sub procedure and I passed the word to be converted by value and the piglatin word byref.Now when I call the procedure in the button click event I get the wavy green line under the variable passed by reference but the program works ok. Call Convert_to_Pig_Latin(strOriginalWord, trPigLatinThe error message when I hover my mouse over the green line says " Variable strPigLatin' is passed by reference before it has been assigned a value. A null reference exception could result at runtime."
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[code].....
Class1:
Dim v as integer
public sub storeVar(byval s as integer)
v = s
end sub
[code].....
I need to save a reference of variable s in Class2 in variable v in Class1.(i.e. when the value of s changes v also changes (and vice versa)Is this possible since vb.net doesn't have pointers?Will it work if I change "byval" to "byref"?
I have a class that I would like to link at construction to a given control (say a textbox)
I know I can put a variable into a subroutine referentially but is there a way to store it in the same capacity?
I have an application consisting of 2 forms (Form1 and Form2).There is a text box on each form and they are both named Text1.From a sub routine in a module, I want to alter a text box on one of the forms. The sub determines which form to write to and attempts to refer to the form using a variable.But in the example below, gForm never gets declared when it's nested within the If statement.[code]The actual application is not so simple and I need to use this or a similar approach throughout the application in order to reduce code redundancy.To recap, I want to alter a control on a form by replacing the form name with a variable name. [code]
View 4 Replies[code]...
In the above code i have created a reference to class B from class A. The reference variable "refB" created as a attribute. But i need to encapsulate this reference variable in a property also i need to ensure than instantiation reB = New B() is done even after the use of properties.
1. How do i encapsulate the class reference variable "refB" in property?2. If i hide this class variable "refB" in a property, how do i write the code code initilize "refB" in "A"'s constructor?
passing a variable to a sub procedure by reference. Not sure I understand how it works. Here is the code.
Private Sub bntcompute_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bntcompute.Click
Dim x, y As Double
getnumbers(x, y)
displaysum(x, y)
[code]....
Is the newly modified variable actually being Passed back? and If so where in the statement is it passed back. is it being passed back to the call getnumbers or is it passed back to the statement displaysum?
I have many textboxes that I need to reference dymanically. The controls themselves aren't dynamic, just the way I need to reference them.I've got several text boxes say:
txtMe1
txtMe2
txtMe3
...
txtMe100
I will need to randomly change one of the properties of the edit boxes. So lets say it picks a random number between 1-100 which is 56. So, I would want to change the background of my 56th edit box to:
txtMe56.Backcolour = Color.Gray
The only way I could think of doing this would be to have one giant select case statement to evaluate the random number. But, that is really dirty and not the best peformance wise (this could potentially get called hundreds of times) so was wondering what my options are?I tried to concatenate the random number to my generic control name 'txtMe' but it throws a wobbler. I essentially would want the following to worK:
dim iNum as integer = 56
txtMe & iNum & .Backcolour = Color.Gray
I have a third party dll. I wish to create a variable to reference to one of the variable in it.so that the value in the class change, my value also change. The senario can be reproduce from the code below.For the code below i wish to get the form to display 2 instead of 1. How can i make my variable test2 always referencing test.testValue?
View 11 Repliesis this safe (I know it works, but is it safe)? Is it returning a reference to a local variable, wich falls out of scope as soon as the function returns?
Public
Function myfunc() As String
Dim strXml As String
[code]....
Im getting the Variable (Data) is passed by reference before it has been assigned a value error.
[Code].....
I'm trying to combine some text and a string value to reference a variable name.[code]
View 4 RepliesI have public variables in a module. I need to get the reference of the variable by using the String name of variable in another formell me how to do this?I need something like the following code:
Dim Var1 As string
Dim sVariableName As String = "Var1"
GetReference(sVariableName).SetValue = "testing"
[code].....
Is it possible to make a variable hold a reference to an integer instead of copying its value when using integerVariable = integerValue ?
View 2 RepliesIn vb.net 2005 how would one referance a control as variable and change it"s properties. Such as in control X visible = True. Tryed string manipulations that did't work.
View 1 RepliesI'm building SQL statements with a bunch of values from a dataset. Obviously that gives some really long names to put inline or even in parameter. addwithvalue code so beforehand I just declare a bunch of variables with really short names and assign them to the DS's exact fields like: [code] but this way I'm putting all the data in the dataset into memory twice by copying it into a new variable, right? So I was thinking, if it's just a string variable representing a field on the dataset, why not declare it by reference so the variable is basically a handy nickname pointing to that field in the dataset.Will it even work to have a string declared by reference and connected to one value inside of a dataset? And if so, will that stop duplicating everything in memory? I forgot how to declare a variable as a reference to another variable instead of the normal way in VB.
View 12 RepliesHow do I reference txtCourse1.text and txtDept1.text using an index variable similar to to code below which does not work?
'two controls on the form
txtCourse1.text
txtDept1.Text
[code].....
How does the GC dispose objects created in the following 2 scenarios?
1)
Private Function DoSomething() As Boolean
Return New DatabaseManager().Insert()
End Function
2)
Private Function DoSomething() As Boolean
Dim mngr As New DatabaseManager()
Return mngr.Insert()
End Function
In Option 1, I don't create local variable to hold the reference of the object. In Option 2, I hold the reference in local variable.What option is better and why? (if any)
, I was wondering if it was possible to reference a member of a structure by using a string variable. Here's an example of what i'm talking about:
[Code]....
Now, I know that you would usually reference the value in any of the members by using the following (String1 in this case)
[Code]....
Dim x = GetType(List(Of )) 'valid statement
Dim list As New List(Of String)
Now I want to see if list is a List(Of T) variable: Dim isList = TypeOf list Is List(Of ) On the last line I get a compile error: "Type Expected". Is there any cheap-performance TypeOf operator alternative for generics?
I've been trying implement Constructor method in passing variable between two forms.Just a rough user interface guide - issue Invoice. User would type in all the Customer Name, Document Number. Once he reached Item Details, a Child Form would pop-up for the User to select/search the Invoice's Item; Once selected, the selected item would showed in the primary Form.
What I had tried is, the Constructor method worked perfectly when it is self-contain in a new project, yet to be implement in my application.But when I implemented, there is an error: Reference to a non-shared member requires an object reference.
[Code]...