Is there a efficient way to provide an Enumarable<SomeType> or a collection that implements INotifyCollectionChanged but that can only be changed from the inside of the providing class.
The following example shows what I mean, but has the disadvantage that the caller can cast the IEnumerable<SomeType> back and then manipulate my internal collection, what I really would dislike:
[Code]...
Is there a way for implementers of an interface where a ReadOnly property is defined to make it a complete Read/Write Property ?
Imagine I define an interface to provide a ReadOnly Property (i.e., just a getter for a given value) :
Interface SomeInterface
'the interface only say that implementers must provide a value for reading
ReadOnly Property PublicProperty As String
End Interface
This means implementers must commit to providing a value. But I would like a given implementer to also allow setting that value. In my head, this would mean providing the Property's setter as part of the implementation, doing something like this :
Public Property PublicProperty As String Implements SomeInterface.PublicProperty
Get
Return _myProperty
[code]....
When it comes to creating trees or collections, sometimes I want child elements to have a reference to the parent. Obviously it is important that the parent and child references to each other remain in sync. It seems natural to have code in the parent "addchild" and "removechild" methods that updates the child's parent reference.t also, the reference to the parent should probably be readonly, so it can only be changed at the appropriate time.Two examples in .Net that I've seen are the TreeNode and datagridview controls
View 11 RepliesHow can I provide an error message if the user does not provide a value in my textbox. I found this example, but it doesn't work in my
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e_
As System.EventArgs) Handles Button1.Click
If TextBox1.Text = "" Then
[code]....
It says that Error Provider1 is not declared. How do I do this the right way?
I have a custom collection, lets says COL, that derives from ObjectModel.Collection. I have my own collection editor that works fine when a property, of type COL, is Read and Write enabled. However, if I change the property to ReadOnly, the open editor button stops showing in the property grid. As a test, I override my custom editor with the CollectionEditor, and that worked fine. So, my question is, what check is the property grid making, that CollectionEditor passes but my collection editor fails?
View 2 RepliesI have a class that has a readonly collection property - Its a list of extender providers that have been applied to the control.I've implemented a simple property descriptor for the collection so that the property can be expanded in the property grid to examine each entry.
When I select an extender provider and set it to false, I remove it from the collection. The GetProperties method of the type converter is requeried and the property grid refreshes.However, when I set an extender provider to true, and thus add it to the collection, GetProperties is not requeried.
Somehow, the property grid is making a distinction between adding to and removing from the collection. Or alternativly, its refreshing when an extender provider is added, but not when one is removed.
[Code]...
I am using a PropertyGrid control to edit my class properties and I am trying to set certain properties read-only depending on other property settings.This is the code of my class:
Imports System.ComponentModel
Imports System.Reflection
Public Class PropertyClass[code].....
This is the code I am using to edit the values:
Dim c As New PropertyClass
PropertyGrid1.SelectedObject = c
The problem is that when I set SomeProperty to True, nothing happens and when I then set it to False again it sets all properties Read-Only.
Provide URL in a toolstrip? I mean to URL that will be displayed as a link.
View 4 RepliesI need to know if a Type implements an interface. [Code] because the Interface IRule itself is assignable of IRule what raises a MissingMethodExcpetion if i try to create an instance:
ruleObj = CType(Activator.CreateInstance(typeAsm, True), Rule.IRule)
UPDATE2: IsAssignableFrom in combination with IsAbstract might be the best way to check if a given type implements an interface and is not the interface itself (what throws a MissingMethodException if you try to create an instance).
If GetType(Rule.IRule).IsAssignableFrom(typeAsm) AndAlso Not typeAsm.IsAbstract Then
I have 2 classes that Implement 1 EventHandler. Its part of a fingerprint scanner API but I'm having some issue and I'm not sure if it is my fault in how i use the Implements.Is it ok to have 2 different classes Implement the same EventHandler? Each class then uses the events differently within the class but it almost seems like there is some overlap that is causing some issues. I know this is hard to explain without posting code but since i can pinpoint the problem, idk what to post. My main point is, can you have 2 different classes Implement the same Interface?
View 1 RepliesIm trying to make a program that implements this but I cant seem to get past inserting the characters. Basicly to get a better idea on what im trying to do look here.Public Function permutation(ByRef charSet As String, ByVal minInt As Integer, ByVal maxInt As Integer)
[Code]...
I've got a web user control (.ascx) which implements a couple of interfaces I wrote; namely IXMLBoundControl and ISectionOverridingControl.I've written a mini-CMS type application that dynamically loads controls onto the page based on information in a database. When I click a button on a web page (.aspx), I want to look at all the controls on that page, and determine if there is a control which implements the ISectionOverridingControl.
I've got my loop and I'm looping through the controls; that's fine. However I'm not sure what the best way is to determine whether or not the control implements the interface. What I'm doing at the moment (and works) is to try to cast each control into the ISectionOverridingControl and catching InvalidCastException: If I don't get the catch; I consider it's worked. If the exception is thrown then it doesn't implement the interface.
It's working, however, I consider this inefficient (relying on exceptions): surely there's a better way in VB.NET (I've seen an example in C# but it didn't convert to VB) to tell whether an instance of a class implements an interface or not?
I'm writing a custom DAL (VB.NET) for an ordering system project. I'd like to explain how it is coded now, and receive some alternate ideas to make coding against the DAL easier/more readable. The DAL is part of an n-tier (not n-layer) application, where each tier is in it's own assembly/DLL.
The DAL consists of several classes that have specific behavior. For instance, there is an Order class that is responsible for retrieving and saving orders. Most of the classes have only two methods, a "Get" and a "Save," with multiple overloads for each. These classes are marked as Friend and are only visible to the DAL (which is in it's own assembly).
In most cases, the DAL returns what I will call a "Data Object." This object is a class that contains only data and validation, and is located in a common assembly that both the BLL and DAL can read.To provide public access to the DAL, I currently have a static (module) class that has many shared members. A simplified version looks something like this:
Public Class DAL
Private Sub New
End Sub
Public Shared Function GetOrder(OrderID as String) as OrderData
[code].....
This cleans it up a bit, but it leaves a lot of classes that only have references to other classes, which I don't like for some reason.Without resorting to passing DB specific instructions (like where clauses) from BLL to DAL, what is the best or most common practice for providing a single point of access for the DAL?
In my propertygrid having one custom property ..suppose some text is there in this item.i want user to allow only delete the item.nothing more like editing ,backspace nothing..only provide delete key option to this property item..
View 4 RepliesI am trying to check if a type implements the generic Icollection interface, since this is a base interface for any of my generic collections.the below code doesnt work
GetType(ICollection(Of)).IsAssignableFrom(
objValue.GetType().GetGenericTypeDefinition())
whats a good way of detecting if a type implements a generic interface?
I have about 1000 webrequest created. Each link will navigate to a website and download a picture to place into a picturebox.
The person will then type in what animal is in the picture into a textbox. Then the user will then hit the submit button to send the name of the animal back to the site.
I am going to implement the use of a thread pool to handle the threading portion of those requests.
What is the best method to get my webrequest into the thread pool (listbox, txt file,etc?) and then how can I setup my button to coordniate with the site that is coming out of the pool to the picture box?
My first thought is to create everything on the fly. The picturebox, the textbox, and the submit button, the webrequest to the site for the picture and back again for the result. Something tells me that I will be taking the long way around to get same result.
My second thought is to have a slew of pictureboxes, textboxes, and buttons already on my screen and then when they come out of the pool and into a thread they would assigned a picturebox, textbox, and button if the others are not busy.
I have an object parameter and I need to check if the object implements a specified interface in vb.net. How to test this?
View 2 RepliesI have about 1000 webrequest created. Each link will navigate to a website and download a picture to place into a picturebox.The person will then type in what animal is in the picture into a textbox. Then the user will then hit the submit button to send the name of the animal back to the site.I am going to implement the use of a thread pool to handle the threading portion of those requests.My question is this:What is the best method to get my webrequest into the thread pool (listbox, txt file,etc?) and then how can I setup my button to coordniate with the site that is coming out of the pool to the picture box?My first thought is to create everything on the fly. The picturebox, the textbox, and the submit button, the webrequest to the site for the picture and back again for the result. Something tells me that I will be taking the long way around to get same result.
View 2 Repliesi have a problem and my project is stop now so i must solve this problem i have a listbox in my project and simple is; so this infos are irregular. i getting this infos with a loop into listbox. i want this infos be sub-bottom.
View 2 RepliesWe build a class (i.e. Server) and create a LOAD method that loads a dataset with all the details of that object.We need all that information sometimes... but what about when we only need one piece of data from that object (i.e. webserviceUrl).Should we build classes with a bunch of scalar methods that get back single pieces of data as opposed to only getting ALL the data and then only taking what we need?It's a waste to get all the data when we dont always need all of it but it also will take longer to write the extra methods..
View 2 RepliesI want to provide a textbox in my windows forms application (in vb.net) that will be masked in time format and validate for time in 12hr format. It should also auto complete i.e if user enters 6 and clicks tab then it should make the text to 6:00 am.
View 3 RepliesI have a need to provide mouse coordinates and click details to the sub-classes of an application. The details are stored in a typed variable in the main class, as they are not processed when the event occurs.
What is the correct way of getting the classes to refer to variables in the parent class that instigated them? I realise this is not standard practise, but at this stage in the project I am converting code from a procedural language and need to do this as an intermediary step. Using the mouse events is also not possible, as this is a DirectX-oriented real-time program, and some things still have to be processed procedurally. They have to be stored via the event and then processed manually.
I may have dozens of instances of the classes, so distributing the mouse data every time it changes is not a good option. Ideally, the class should be able to retrieve the data when it needs it.
Let's say I have 2 interfaces defined like so:
public interface ISkuItem
{
public string SKU { get; set; }
}
[Code]....
VB.NET explicitly requires you to add Implements IInterfaceName.PropertyName after each property that gets implemented whereas C# simply uses regions to indicate which properties and methods belong to the interface.
Interestingly in VB.NET, on the SKU property, I can specify either Implements ISkuItem.SKU or Implements ICartItem.SKU. Although the template built by VS defaults to ISkuItem, I can also specify ICartItem if I want. Oddly, because C# only uses regions to block out inherited properties, it seems that I can't explicitly specify the implementing interface of SKU in C# like I can in VB.NET.
My question is: Is there any importance behind being able to specify one interface or another to implement properites in VB.NET, and if so, is there a way to mimic this functionality in C#? Furthermore, what is the effect of specifying one interface over another when implementing properites?
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].....
I have an interface, for the sake of argument called MyInterface.I Have a Control Class, lets name it "Parent" that implements MyInterface.I have another Control Class that inherits Parent, called "Child".I have a final Control Class lets call it "Container", that accepts dragging the parent onto it.[code]I want to modify this not to only accept Parent, but to accept ANYthing that implements MyInterface. I can't figure out how the heck to get it to work. Even more confusing, if I drag the child onto Container, with the code as it is above(checking to see if a Parent was dropped), GetDataPresent always returns false. I would figure it would work, since Child inherited parent.[code]But it bombs and GetDataPresent returns false whether I dragged a Parent or a Child. I'm being an idiot somewhere..
View 1 RepliesI use the IsAssignableFrom-method to check if the datasource of a bindingsource-object implements an interface i defined. The check happens inside the property-setter like this:
Private WithEvents _BindingSource As BindingSource
''' <summary>
''' BindingSource containing datasource in which search is executed.
''' </summary>
''' <remarks>Datasource must implement ISearchAndFindable.</remarks>
<Description("The BindingSource to search within."), Category("Data")> _
Public Property BindingSource() As BindingSource
[Code] .....
When I build my VB.NET 2008 Express Edition project I get the following error
The designer loader did not provide a root domponent but has not indicated why
I though this meant that I need to put my Acces mdb in the root folder of the project but that didn't help. why I'm getting this error? If I click on more information I get an message saying information not found.
I want to make a user control (name MultiSelect), which I will use for choosing items from huge list. For example I want to choose customers to make a view of their turnovers, so I will creat a new MultiSelect control which will contain a textbox (i canwrite starting letters) and a treeview (will list customers matching the first letters chosen in textbox).
View 7 Repliescreating a simple pong type game. want to provide human user option to choose from "rookie , Veteran, Allstar" as CPU AI skill.
Q1 - currently on form load game starts (I do not want) I want to present list of options first. Player Skill Level *See above.
Q2 - Want to provide an option for who gets the ball first CPU or Human
Q3 - Want to choose "Game to #" the user can set as the first to score x points wins.
I would like to provide an effective way for my VB.NET application to get registered automatically in a company with many computers. So the Enterprise Licence would kick in, but how to manage this?I was thinking each computer would connect to an intranet server where he would get the permission to register...C64
View 2 Replies