Can't Find The .net Equivalent Of A Variable Type Of A "raw" Generic List That Takes A Wild Card?
May 17, 2012
I'm strictly looking for a language conversion here of this:List<?> I already have a work around I'm just surprised that I can't find the vb.net equivalent of a variable type of a "raw" generic list that takes a wild card.Java's mechanism here enables you to reference a list regardless of what T is.Java even enables you to go further and do things like:
List<? extends Number>
List<? super Double>I tried:
List(Of )
and that did not work. That only seems to work inside the GetType function.
I am converting DataTables to a generic list and need a quick and easy way to implement a Find function. It seems I am going to have to use a Predicate. Upon further investigation, I still can't seem to re-create the functionality. Private Function ByKey(ByVal Instance As MyClass) As Boolean Return Instance.Key = "I NEED THIS COMPARISON TO BE DYNAMIC!" End Function
Dim Blah As MyClass = MyList.Find(AddressOf ByKey) But I have no way to pass in a key variable to this predicate to do the comparison, as I used to do with DataTable..Dim MyRow as DataRow = MyTable.Rows.Find(KeyVariable) How can I setup a predicate delegate function in VB.NET to accomplish this?
Do not recommend LINQ or lambdas because this is question is regarding .NET version 2.0.
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?
How would i add a wild card for a directory, my code is reader = New IO.StreamReader("C:Program FilesStattrackconfigconfig_misc.txt"). i want the C: to be a wild card this way that if the computers local-disk is Z: then it will adjust to it.
I am trying to insert a wild card character (') in sql database, but error is coming that STRING IS TRUNCATED.
Text1.text="D'John Is Writing Dev's Books"
Here there are 2 wild characters (') in the text. When i try to insert this text in database, the problem is comming. The whole string should be inserted as it is, as well as to be retrieved as it is.
I'm using Visual Studios 2008.I'm building an app that will migrate a user's Desktop, Fav's, My Doc's, and I need the last piece to scan the C drive for .pst and .nk2 files. Does anyone know how to do that? I found the following code on the How To from MSDN.[code]
I 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.
Im trying to make the below statement as such if there is no items selected/blank then the search term is a wild card (all results) otherwise search it. the sql below only works when all fields match, not partial
I have the following code. I would like to perform a if then check via a button click before the user processes the information.
Private Sub TestBTN_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TestBTN.Click If TBSearch.Text = "" & ".exe" Or TBSearch.Text = "" & "" Or TBSearch.Text =
[Code].....
I would like it to just check to see if the text box info has been entered in one of three formats.
Public Class notifierMain Public Class Contacts Inherits List(Of row) Public Sub New()
[code]....
When I debug this winforms application I get curType = "notifier.notifierMain+Contacts+row" I want to the Validate function to know it is in MyContacts. How do I do this?
i m getting a collection of data in list's object. And from this list i want to get the maximum id.`
Dim objinfo As List(Of AlbumInfo) = objPhotos.GetPhotos_Alb_ID(Me.ModuleId, hdd_AlbID.Value) Dim Photo_Image As String = "" Dim str As String = Photo_Image & fu_Photo.PostedFile.FileName.Substrng(fu_Photo.PostedFile.FileName.LastIndexOf("."))
[code]....
this returns the "0"th positions id from Convert.ToString(objinfo.Item("0").Photo_Id + 1)but i want to get the last item's id.
I'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?
I want to create a generic list - but I want to specify the type at runtime - is there a way I can do this? using reflection perhaps?Something like this...
Public Shared Sub create(ByVal t As Type) Dim myList As New Generic.List(Of t) End Sub
I'm trying to use a generic list without knowing the type when loading the page. I have a typePropertyCollection which inherits from List(Of PropertyData). The usercontrol that uses this collection doesn't know what type of data is used (which objects). So when the page is loaded, I pass along the type to the usercontrol using a dependencyproperty. This type ends up in this method:
Private Shared Sub OnObjectTypeChanged(ByVal obj As DependencyObject, ByVal args As DependencyPropertyChangedEventArgs) Dim objectType As Type = TryCast(args.NewValue, Type)
I would like to write a generic function that would search a List(Of T) for all elements of type TFilter and return a List(Of TFilter) which comprises those elements.
I've tried this: Public Function FilterList(Of T, TFilter)(ByVal ListToFilter As List(Of T)) As List(Of TFilter) Return ListToFilter.FindAll(Function(z) z.GetType.Equals(GetType(TFilter))).ConvertAll(New Converter(Of T, TFilter)(Function(z) CType(z, TFilter))) End Function
But, it gives the following error: Value of type 'T' cannot be converted to 'TFilter'.
I have converted c# .cs to vb:= I have 6 errors on:
Red "List" says Too few type arguments to system.Collections.Generic.List(Of T)' Orange "Calendar" says Value of type 'System.Windows.Forms.Control.ControlCollection' cannot be converted to 'Form1.Kobush.Windows.Forms.Appointment'.
I need to be able to tell if a property is of type List(of T)but am currently unable to. if i do
TypeOf (UpdateTo.GetType.GetProperty(node.Name)) Is System.Collections.Generic.List(Of Object)
I get the following error
TypeOf (UpdateTo.GetType.GetProperty(node.Name)) Is System.Collections.Generic.List(Of Object) Expression of type 'System.Reflection.PropertyInfo' can never be of type[code]......
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.
I recently downloaded VB 2010 Express so i am quite new to the language, but i have worked with dark basic, which seems to b very similar.Anyway, my problem is that i cannot seem to correctly set out my array of a custom type/class. i am trying to create two arrays, one of available entities and another of selected entities of which the user selects the entities to be dealt with in irrelevant ways. i have creates a button (called test) which adds some entities to the available list and all the entities come back the same value but they shouldnt be as you'll c in the code. i have run the step into command a found that "available.item(#).Name = " will change all of the entity's names.As of current i am working with lists as the array kept asking for a 'new' statement but i couldnt figure out where to put it.[code]
I 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).
I'm compiling a VB.Net 2.0 app (created in VS2008) using msbuild, and now I've added a generic return type, it's giving me the following:
Warning: Type library exporter encountered a generic type instance in a signature. Generic code may not be exported to COM.
Having just spent ages removing all of the previous warnings, I don't really want to add a new one. Any idea how to get rid of it (aside from not using generics)?I don't know what details I'd put in the attribute, or what number to put in the project-level ignore list.
