Create A Generic Property?
Dec 8, 2009
I'd like to do something like this:
Private _myCollection As IList(Of T)
Public Property MyProperty(Of T)() as IList(Of T)
Get
[Code]....
Basically, I want to have a collection of items that may be of any type. Then, I'll be able to do something like this:
Dim myPropertyValue as <the type of some value>
if (MyProperty.Contains(<some value>))
myPropertyValue = CType(MyProperty(<some value>), <the type of some value>)
How can I do this? Or is there a better way than using a generic type?
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Mar 8, 2011
I'm attempting the following:Default Public Property Data(Of dataType)(ByVal key As String) As dataType
Get
Return DirectCast(values.Item(key), dataType)
End Get
Set(ByVal value As dataType)
values.Item(key) = value
End Set
End Property
[Code]...
It made more sense to make it a property, and it would be the default property of the class. The data type can not be specified on instantiation of the class, because it can contain multiple objects of different data types.
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Oct 15, 2009
I'm attempting the following:
Default Public Property Data(Of dataType)(ByVal key As String) As dataType
Get
Return DirectCast(values.Item(key), dataType)
[code].....
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Jul 9, 2010
I'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)?
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May 29, 2010
I have a routine that accepts a List of Objects, a property name and a value to search for and simply returns whether or not it found it.The code I have hangs up at the For loop in the findit routine.[code]
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Apr 10, 2012
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]......
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Jun 19, 2009
I have several custom classes in a VB.NET (VS2008) project which are related to each other through generic list collections. The lower tier classes refer directly to some of the parent classes (to make it easier to refer backwards up the chain). My question is, is it possible to add the reference to the parent class when the item is added to a collection, when that collection is a property?
Below is some sampling of code to illustrate.
Public Class FlexServer
Private m_FlexLicenses As List(Of FlexLicense)
Private m_Modules As List(Of FlexModule)
Public Property FlexLicenses() As List(Of FlexLicense)
[code] .....
In the code above I have the FlexServer class which refers has two lists as properties, one for FlexLicense and one for Modules. The FlexLicense class has a property to refer back to the FlexServer class that "owns" it. In order to update this property in code, I have to add the FlexLicense to the FlexServer.FlexLicenses list AND set the FlexLicense.FlexServer property. What I am looking for is, is there a way (in the property definition or wherever) to both add the item to the list and alter it at the same time?
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Dec 16, 2009
We 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.
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Apr 28, 2010
I am really trying to follow the DRY principle. I have a sub that looks like this?
Private Sub DoSupplyModel
OutputLine("ITEM SUMMARIES")
Dim ItemSumms As New SupplyModel.ItemSummaries(_currentSupplyModel, _excelRows)
ItemSumms.FillRows()
[Code]...
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Apr 1, 2009
I am attempting to create a generic function that the students in my introductory VB .NET course can use to search a single dimension array of a structure.[code]...
My question is: Is there a way to reference the individual structure fields in the array from inside the function? I was trying to make it generic so that the student could simply pass their array into the function - their structure may be named differently than mine and the field names may be different.
I suspect there are other ways to deal with this situation, but I was trying to keep it to just a simple single-dimension array of a structure. I don't think it is possible to do what I want, but I wondered what others thought.
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Apr 19, 2010
I was trying to create a generic Dictionary that implements IXmlSerializable (credit to Charles Feduke).
Here is my trial:
Sub Main()
Dim z As New SerializableDictionary(Of String, String)
z.Add("asdf", "asd")
[Code].....
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Aug 2, 2010
I need to create a generic for all the classes having common data.I am having a Test.xsd dataset.In that dataset I am having 3 Table Adapter.
pgaddressTableAdapter1
pgaddressTableAdapter2
pgaddressTableAdapter3
Code is here. You can see all these classes having same methods. I want to create a generic class for these class.
[Code]...
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Mar 19, 2010
How can I create a generic constructor? (ie. BaseClass.FromXml(<param>). I'm not sure how to describe this but I'm trying to create a base class that contains a shared (factory) function called FromXml. I want this function to instantiate an object of the proper type and then fill it via an XmlDocument.
For example, let's say I have something like this: [Code]
I'd like to be able to do something like this:
Dim myObject As CustomObject = CustomObject.FromXml(source)
Is this possible?
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Oct 1, 2009
I'm looping all the properties in an object via reflection:
For Each p As PropertyInfo In values.[GetType]().GetProperties()
If p.CanRead Then
'Do stuff
End If
Next
how to determine whether the property in question is a generic List(Of T)? If it is I need to loop the list itself.
I've experimented with GetType and TypeOf but have not managed to get anything working.
To clarify, I want to keep this generic. I do not want to specify the type of T, I need to loop the list items and call the ToString method on each item. T could be one of a number of different types (application specific reference types). Is it possible to do this without specifying types?
(VB.NET 2005 with .Net 2.0)
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Jul 9, 2009
I'm trying to create a generic ListView user control that can be used over and over again in different projects. I've got all the basics done but I want to be able to act on click events in the from not the user control. In other words if someone right clicks on the listview, for example, I want the form to know it and be able to act on it.
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Feb 14, 2011
say I have two POCOs I'm using in EF code first
Public class C1
property F1 as integer
End Class
Public class C2
property F2 as String
End Class
I want to have a function that will create a list either of C1 or C2, to be used in some generic operation, such that
[Code]...
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Jan 27, 2010
I have an interface that i have declared some of the basic internal functions, subs, properties, etc. This interface is then implemented into 3 pre-defined classes. These classes are end-use classes so they dont get derived or inherited elsewhere. I am trying to create a generic shared class that can operate on each of these 3 predefined classes and potentially more as long as they implement the interface.
[Code]...
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Oct 20, 2009
I'm sort of repeating the same steps. There's got to be a way to shorten it.I was able to shorten it before by making a generic function to create the radio buttons.This is the before the rewrite
Public Sub LoadPanels(ByVal tblClient As DataTable)
Dim count As Integer = 20
Dim tooltip As New ToolTip
Dim countName As Integer = 0
[Code]...
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Sep 13, 2011
I am trying to create a property which is as a class, which contains other certant properties you can edit, i.e:
Public Class exampleClass
Dim _var1 As String
Dim _var2 As Integer
[Code]....
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Sep 17, 2008
I am trying to create bitmap with my text and transformation. I am sure that there is no error in my code. Because this code is worked previously. Here is my code.
[Code]...
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Apr 13, 2012
Consider:
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.
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Aug 14, 2010
I have a Journal that records entries for different types: Journal(Of ParentT)
[Code]....
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Nov 25, 2011
I 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]
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Jun 30, 2011
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.
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Feb 8, 2012
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).
[Code]...
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Jul 21, 2011
I'm trying to create a generic IsEmpty extension but am having problems specifically with dictionaries: The functions I have created:
<Extension()> Function IsEmpty(null As DBNull) As Boolean
Return True
End Function[code].....
For my purposes, booleans and numerics are never "empty".The problem is that dictionaries are using the generic (Of T)(val As T) function instead of the (collection As ICollection) function.
i.e.
Dim dict As New Dictionary(Of String,String)
Response.Write(dict.IsEmpty)
output is "False"
I tried using (Of K,V)(collection As ICollection(Of KeyValuePair(Of K,V))) to no avail.What am I doing wrong?
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Jun 19, 2012
If 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
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Apr 7, 2009
I am trying to create a delegate(as a test) for: Public Overridable ReadOnly Property PropertyName()As String My intuitive attempt was declaring the delegate like this:
[code]...
So the question is, how do I make a delegate for a property?
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Jun 9, 2009
I am trying to create a property for objects, though I am not sure if that is what it is called. For example, PictureBox.Image instead of Image I want to use my own property.
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Mar 11, 2012
I want to create a property handler in .NET. I have already implemented the IInitializeWithFile, IPropertyStore and IPropertyStoreCapabilities classes but I don't know how to implement their functions to create custom properties and display data.[url]...
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