Make Passing Generic Lists
May 6, 2009I have a utility class that takes a generic list as a parameter.Code looks like:
Function DoStuff(collection as Object, elt as Object)
...
collection.Add(elt)
[code]....
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.net - Compare Different Generic Lists?
Mar 2, 2011I have a method where I'm taking a generic object and using TypeOf to check what has been passed through. Now I would like to pass it a List(Of T) (T being anything) and no matter what T is I'd like to do the same thing to this list. I tried the following:
public sub foo(ByVal obj As Object)
if TypeOf obj Is List(Of Object) Then
'do stuff
end if
end sub
but this doesn't seem to work if I pass it List(Of String), say. I suppose that List(Of Object) and List(Of String) are being treated as different objects, but I thought that since String is an object, the comparision might work.
Now I realise that this is as ugly as sin and I'm better off overloading the method to take List(Of T) as its parameter, but I'm mostly asking out of curiosity: is there a way of comparing the types List(Of Object1) and List(Of Object2) and getting a positive result, since they are both just List(Of T)?
.net - Comparing Two Generic Lists On A Specific Property?
Jul 9, 2010I'm using VB.NET with .NET 2.0. I have two lists, and I want to compare the lists on a specific property in the object, not the object as a whole, and create a new list that contains objects that are in one list, but not the other.
myList1.Add(New Customer(1,"John","Doe")
myList1.Add(New Customer(2,"Jane","Doe")
myList2.Add(New Customer(1,"","")
Result in the above example would contain one customer, Jane Doe, because the identifier 2 wasn't in the second list.How can you compare these two List<T> or any IEnumerable<T> in .NET 2.0 (lacking LINQ)?
VS 2005 - Generic Lists Of Unknown Type
Sep 14, 2009I have recently moved from VB 2003 to VB 2005. While I am finding a lot of the new features quite useful, I am having trouble with List (of T). I want to be able to do something like this
Function GetList(MyObjectType as Type) as datatable
Dim list as new List(of MyObjectType)
End Function
Function GetList(MyObjectType as String) as datatable
Dim list as new List(of GetType(MyObjectType))
End Function
VB 2005 does not allow me to do this at all. Must the "type of" be srongly declared at all times? Can't this be done dynamically?
Passing Lists From WCF To WCF In VB?
May 13, 2011I'm trying to populate one list from another. I would think this code should work, but at the end of the day I get a list of identical items.
Public Sub WriteDatFile(ByRef lstReasons As System.Collections.Generic.List(Of LetterReason))
Dim tmplstReason As New TCPService.LetterReason
[Code]....
Generic Lists Copying References Rather Than Creating A CopiedList
Mar 8, 2010I was developing a small function when trying to run an enumerator across a list and then carry out some action. (Below is an idea of what I was trying to do. When trying to remove I got a "Collection cannot be modified" which after I had actually woken up I realised that tempList must have just been assigned myLists reference rather than a copy of myLists. After that I tried to find a way to say
[Code]...
Passing A System.Collections.Generic.List To Another Class?
Jun 10, 2012I am trying to pass a System.Collections.Generic.List to another class. The collection is created in class2 and then passed into class1
[code]...
However I get a 'Null Reference Exception error' when I run the program. It seems f_str in the line 'For Each s As String In f_str' is null.
C# - .NET Generic Class Instance - Passing A Variable Data Type
Jun 2, 2010I'm tyring to pass a variable data type to a template class. Something like this:
frmExample = New LookupForm(Of Models.MyClass) 'Works fine
Dim SelectedType As Type = InstanceOfMyClass.GetType() 'Works fine
frmExample = New LookupForm(Of SelectedType) 'Ba-bow!
frmExample = New LookupForm(Of InstanceOfMyClass.GetType()) 'Ba-bow!
[Code].....
I'm assuming it's something to do with the template being processed at compile time but even if I'm off the mark there, it wouldn't solve my problem anyway. I can't find any relevant information on using Reflection to instance template classes either.
(How) can I create an instance of a dynamically typed repository at runtime?
Make Mulitple Drop Down Lists On Form?
Oct 20, 2010ok, I'm basically trying to make mulitple drop down lists on my form. When the page loads, I can get my main dropdown list, called makelist, to fill in with the items that I want from a txt file.
What I'm trying to do is whenever the selectedindex is changed in makelist, it has to load a different dropdown list, called modellist with items from a different txt file.
[Code]...
Make Some Single Dimension Array Lists?
Sep 7, 2010I've managed to make some single dimension array lists but I can't figure out a multi dimension arraylist.
Here's what I'm trying to do:
I have a database (mdb) with 5 columns that I want each row to be in an array list.
In PHP what I'd typically do is:
$array[$field1] = array($field2,$field3,$field4,$field5);
How I do the same in vb.net so anytime I need to fetch an item for a specific for the row1 I could call it?
For a single dimension I could do the following, but I can't figure out how to add more fields to a single array row:
Dim tmpArrayX As New ArrayList
tmpArrayX.Add(field(0))
tmpArrayX.Add(field(1))
etc...
Make The Default Modelbinding Handle Lists?
Jul 9, 2011How do I make the default modelbinding handle Lists?
Let's say I have a ShoppingCart class, which has a ShoppingCartItem List:
Public Class ShoppingCart
Public Property CouponCode As String
Public Property Items As New List(Of ShoppingCartItem)
End Class
[Code]....
However, when I submit the page, no values are picked up, not even the CouponCode field. The model object is empty. What gives?
Ultimately, my goal is to add/remove items clientside via javascript and then have the modelbinder pick up the changes automatically when the page is submitted.
Update: I was just missing the Property keyword from my model properties declarations. It's too late, and I got to get some sleep. :)
Sql Server - Make An Unordered Lists Of Reverse Chronological Dates In Asp.net 2.0 With Vb
Jan 3, 2012I need to create an unordered list of dates for a news items archive... It should look like this
2011
Dec
Nov
[Code].....
I can carry on with this adding in the for loops for months nested under each year however it doesn't seem very practical and will generate links for months even if there are no news item entries...
Is there a way I can build this tree automatically and only include the years/months that have news entries. I can pull a list of SQL Server timestamps from the DB for all the news items and then would like to populate the list based on that...
Sorting 2 Lists Based On Only One Of The Lists?
Apr 1, 2011I have two lists. One list is a list of names, the other list is a list of how many times each name is found in the first list noted in the database
so...
Nick
John
Jim
Jack
is the firs tlist
10
13
13
2
is the second list. Nick had 10, john 13 and so on.I want to sort the second list from large to small, but have the index for the first list still linked to the correct amount of calls.i do it this way so I can
for x = 0 to num_of_names
string = lst_name(x) & "-" & lst_count(x)
next x
Is There A Concept Of "Generic Structure" Similar To Generic Collections, Generic Classes
Dec 16, 2009We have migrated our Vb6 application to VB.NET using a third party tool. Now we are in a process of Refactoring and introducing object oriented concepts in the application.
In VB6, we were using structures in many places. As a part of introducing object oriented programming,
1. is it a good idea of changing all Structures to Classes? or Is there a concept of "Generic Structure" similar to Generic collections, Generic classes?
2. Can some one guide me any source containing guide lines or best practices for applications that are migrated to VB.NET from VB6 and implementing object oriented programmaing.
.net - How To Make Function Return Generic Value
Sep 16, 2011I have an abstract class in VB.NET. I want all classes that inherit from this class to return whatever value makes sense. For example, it could be an Decimal, Integer, String. How can I delcare the function in the abstract base class to allow for this? Is this even possible?
[Code]...
Make A Shared Function Generic?
Feb 16, 2011I can create classes that use generics, however I was wondering if it is possible to apply this to a shared method rather than rely on the caller casting to the correct type.This is the method:
Public Shared Function DeserializeObject(ByVal serializedXml As String, ByVal givenType As System.Type) As Object
Dim serializer As New XmlSerializer(givenType)
Return serializer.Deserialize(New IO.StringReader(serializedXml))
End Function
I'm pretty sure this can't be done, but thought I'd check (if so Extra points will be awarded if someone can technically explain why the compiler can't do this)..
C# - Make A Function With Return Type Generic?
Apr 29, 2010Currently I have written a function to deserialize XML as seen below.How do I change it so I don't have to replace the type every time I want to serialize another object type ? The current object type is cToolConfig. How do I make this function generic ?
Public Shared Function DeserializeFromXML(ByRef strFileNameAndPath As String) As XMLhandler.XMLserialization.cToolConfig
Dim deserializer As New System.Xml.Serialization.XmlSerializer(GetType(cToolConfig))
Dim srEncodingReader As IO.StreamReader = New IO.StreamReader(strFileNameAndPath, System.Text.Encoding.UTF8)
Dim ThisFacility As cToolConfig
[code]....
Make Base Interface For Generic Classes?
May 25, 2010I'm trying to create a base interface for a class of mine that uses generics. However, I cannot figure out how to declare a property of the interface when its type won't be defined until the class is initialized.
To clarify, consider List(of T), which according to msdn, implements IList (among other things). Note that IList is not the same as its generic counterpart IList(Of T). So that mean any List(of T) can be converted to IList, which simply returns an object for its items. That's what I want to do with MyClass(of T), be able to cast it as IMyClass regardless of what T is.
But when I try such as:
Interface IMyClass
Prop A as Object
Class MyClass(of T) Implements IMyClass
Prop A as T Implements IMyClass.A
I get a signature error for the last line, even though object is broader than T. What am I doing wrong, or how exactly did Microsoft manage to make List(of T) implement IList?
Make Several Similar Properties Call One Generic One?
Sep 14, 2011I'm wondering if it's possible in VB.NET to make similar properties call one generic one?A sentence doesn't explain it well so here's a code example.I have a bit field defined like this:
<Flags()> _
Enum E_Operation As Integer
Upload = 1
[code]....
.net - Can A Generic Version Of A Derived Class Override A Base Method Using The Generic Type
Apr 13, 2012Consider:
Public MustInherit Class Column
Public ReadOnly Property ReturnSomethingUseful() As Object
Get
'return something useful
[code]....
But this gives the following error:
Public Overrides Function ParseValue(sValue As String) As Boolean'
cannot override 'Public Overridable Function ParseValue(sValue As String) As Object'
because they differ by their return types.
I accept that you can't do this, but I'd like to be able to preserve the semantics of what I'm. trying to do, which is to have an untyped version that deals with Object, but a typed version in derived classes that knows about the specific type T.
.net - Determining A Generic Type At Runtime In Non-Generic Class
Aug 14, 2010I have a Journal that records entries for different types: Journal(Of ParentT)
[Code]....
Construct A Generic Interface Class With Generic Functions
Nov 25, 2011I am trying to construct a generic interface class with generic functions. My goal was to use this to implement multiple worker classes for database interaction that have the same basic functionality. Each class will deal with different object for example, category, product or supplier but unless the the functions in the interface are generic that this won't work.This is the interface code that I have but I don't know if I have done it correctly. [code]
View 2 RepliesMake A Function Passing Array Paramters In VB6?
May 19, 2010i make a function passing array paramters in VB6 Public Function PolCoefCalc(pT() As Double, pU() As Double, pN As Double, pA() As Double) As Double
Dim return as double
returnStatus = 0
PolCoefCalc = returnStatus
End Function
[Code]...
Know If An Array Of Lists Contains Similar Items (similar Lists)?
May 20, 2010I know how to check whether an item exists in a list using (MyList.Contains), But I do not know how to check the whole list. For example (use one button and one richtextbox):
[Code]...
.net - Creating A Generic List Of A Generic Type
Jun 30, 2011I am trying to create a list of a generic type in vb.net 2.0 framework.
This is the generic type definition:
Public Class GenericParamMap(Of T)
Public Sub New(ByVal pParamName As String, ByVal pPropValue As T)
mParamName = pParamName
[Code]....
The compiler does not allow a "T" in the method's parameter because it's not defined, but I'm not sure how or where to define it. I thought it was okay to have a generic method definition.
Generic Cannot Instantiate Instance Of The Generic Type With New?
Feb 8, 2012I am trying to write a generic method, to avoid code duplication, which will create or activate a Form as an MDI children, based on its type. But I have to lines in error (see comments).
[Code]...
VS 2008 Accessing Something With A Generic Generic?
Jun 19, 2012If i have an object that implements an interface (and don't know the exact object) i can call a sub (DoSomething) by going:
vb
Dim iObj = trycast(something, iInterface)
if iObj isnot nothing then
iObj.DoSomething()
end if
How can I do this for a Generic? such as...
vb
Public Class TestClass(of T)
Public sub DoSomething()
....
end class
Make Stand Alone, Custom Web Browser (with Custom Errors, Or Generic)
Dec 13, 2011Cookies to be stored in folder and on close delete the cookies The ability to watch youtube vids, view images, and play js/flash games good security, no ads?
View 6 RepliesMultithreading - Modify A Generic Invoke Method To A Generic BeginInvoke Method?
Oct 7, 2010I have been using a pretty slick generic invoke method for UI updating from background threads. I forget where I copied it from (converted it to VB.NET from C#), but here it is: Public Sub InvokeControl(Of T As Control)(ByVal Control As t, ByVal Action As Action(Of t))
[Code]....
Overload Operator In Generic Class With Generic Interface Of Super Class And Inherit Class?
Jan 21, 2010I can do this without problem.
Class A
End Class
Class B : Inherit A
End Class
Dim Obj1 As A = New B
