Require That A Class Is A Windows.Forms.Control And Implements An Interface?
Nov 29, 2011
I'm not sure that I'm doing the right thing here..I'm writing a user control that's supposed to be (fairly) generic. It's a bit like a modified email client specifically tailored to some of the internal things we do.
The view is composed of two main pieces, a message list and a viewer. I need this viewer to be interchangeable, so if someone wants a different style of view they can simply handle an event and change a property. My original idea was to just have an INoteViewer, but since I'm adding it to my form I also need to guarantee that this object is a Windows.Forms.Control of some sort.
Should I continue along these lines and maybe raise an ArgumentException if I can't cast it to INoteViewer, or should I go a different direction and create a class that inherits from Windows.Forms.Control?
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Apr 9, 2010
I am trying to create a class in VB.NET which inherits a base abstract class and also implements an interface. The interface declares a string property called Description. The base class contains a string property called Description. The main class inherits the base class and implements the interface. The existence of the Description property in the base class fulfills the interface requirements. This works fine in C# but causes issues in VB.NET.
[Code]...
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Dec 4, 2009
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?
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Apr 18, 2012
I have an object (a third component gridview) which is serializable, and I need a deep clone of this object. I have the following code which throws the exception."The type System.Windows.Forms.Control in assembly System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKey Token=b77a5c5 61934e089 is not serializable".So the gridview's base class is System.Windows.Forms.Control, which is not serializable. How can I get a deep clone from the gridview? [code]
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Sep 24, 2009
I have cooked up my first iteration of a code generator which creates the basic Entity models from a SQL Database Schema. Currently, It will scan a SQL Db Schema, and create .vb code files complete with private members and Public property declarations for every User table in the Database. My next step is having it add the basic CRUD procedures as well. Are we mere mortals able to access whatever technology allows the Partial class files created by vs to be hidden/Linked to their "parent" files, such as the Partial Class files for Windows forms or any other designer-generated control? My thinking is that it would be handy to be able to re-generate code files from the database if necessary to reflect changes in the schema, without overwriting any other properties or methods added to a class in addition to those derived from the database. SO I am hoing I can have the Auto-generated output go to a Partial Class file, and then use a regular class file of the same name for the rest of the code. My Concern is the multiplicity of files that might result, so I was hoping it is possible to "tuck them in" to the parent code file in the Class View.
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Mar 12, 2010
When I do this
Public Class cInherits : Inherits Panel
I get this: Base class 'System.Windows.Forms.Panel' specified for class 'MenuButton' cannot be different from the base class 'System.Windows.Forms.UserControl' of one of its other partial types.
How do I inherit?
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Oct 25, 2010
I 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
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Sep 1, 2009
I have an object parameter and I need to check if the object implements a specified interface in vb.net. How to test this?
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Sep 2, 2010
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..
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Jun 5, 2011
I 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] .....
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Jun 23, 2012
I had a look through the documentation on the Wiki, but it seems a bit thin. How do I determine if a type implements a given interface using Cecil? For my particular implementation it is important that I do not actually load the type into the AppDomain.m Here's the code that I have so far:
Dim outputModule As ModuleDefinition = ModuleDefinition.ReadModule(outputFile)
For Each assemblyType As TypeDefinition In outputModule.Types
'How to determine if assemblyType implements a specific interface?
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May 9, 2012
can someone please help me with a textbox? I have created a new class and require this textbox field within a sub in the new class but i get Error1 'TextBox1' is not declared. It may be inaccessible due to its protection level.I have tried MyClass.TextBox1 = Form1.TextBox1 but I get declaration expected.
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Oct 19, 2010
im new to the forums but I have some experience with vb.net.I want to create a windows application that has the ability to allow a user to "login" to the application via the internet and a website that the application serves, and lets the user interact with the program ie change settings etc. I have seen this done with many applications, almost like a web interface back end. Sorry I can't be more clear
I have searched all over the internet but can't find any examples or starting points. Maybe im using the wrong key words I dont know if there is a name for this type of thing.
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Feb 22, 2011
I'm struggling how to set up MDI interface where I have a tabpage control on the parent form. Each individual tab page should act as a parent to multiple child forms but within a tabcontrol there is no IsMdiContainer property like on the form.Is it possible to set a tabcontrol to act as a parent?
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Jun 27, 2010
I am working on an application and I want the user to be able to enter commands into a textbox, and when they press enter, the command is printed in a rich text box, executed, and the output is printed. For instance: the user types move{file1}, {location} into the text box and this happens:
>command: move{file1}, {location}
>$ moving file1 to location
>job completed
How would I write lines to the rtb and execute commands when the enter key is pressed?
This works, partly.
Private Sub TextBox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles command.KeyPress
If e.KeyChar = Microsoft.VisualBasic.ChrW(Keys.Return) Then
RichTextBox2.Text = Environment.NewLine + command.Text
End If
End Sub
it erases everything in the textbox before adding the line... I would also like to be able to make a database of commands, maybe a .dll or something, so that when the user types in something, it checks that database to see if the command exists, if it does it executes, if not, error.
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Jun 7, 2010
When I write the following statement in VB.Net (C# is my normal language), I get an "end of statement expected" referring to the "Implements" statement.
<Serializable()> _
<XmlSchemaProvider("EtgSchema")> _
Public Class SerializeableEntity(Of T As {Class, ISerializable, New}) _
Implements IXmlSerializable, ISerializable
...
End Class
The C# version that I'm trying to emulate is:
[Serializable]
[XmlSchemaProvider("MySchema")]
public class SerializableEntity<T> : IXmlSerializable, ISerializable where T : class, new()
{
....
}
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Dec 15, 2010
I have an interface 'ICRUDable' and a class called ClientAddress which implements the ICRUDable interface.
My understanding of OOP would lead me to believe that if I declare a System.Data.Linq.Table(Of ICRUDable) then I should be able to put ClientAddress's in there.
The code I have tried includes;
Dim dc As New CRMDataContext
Dim items = dc.ClientAddresses
and
[Code]....
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Sep 8, 2010
I have the code which checks if there is a selected tab
Private Function GetBrowser() As WebBrowser
If TabControl1.SelectedTab IsNot Nothing Then
For Each c As Control In TabControl1.SelectedTab.Controls
If TypeOf (c) Is WebBrowser Then
Return c
[Code]...
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Feb 12, 2009
I Need Build a user control which works as a Login control using Windows Class Library or Component Template:The user control returns the user name and the password It means that the control has minimum two ReadOnly Property procedures. You let the user of your control (he/she which uses your control in his/her software) to set the background colour of the two labels. Create a Windows application to test your control.
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Jan 17, 2009
I have an interface class (IUser) which is the interface of class User. Now, i want to put these into an IList but am confused as to how i should declare the IList:Dim userList As IList(Of IUser) = New List(Of IUser) Dim userList As IList(Of User) = New List(Of User) Dim userList As IList(Of IUser) = New List(Of User) Dim userList As IList(Of User) = New List(Of IUser) when instantiating should you always use its implementation; and when using it as a type use its interface?
And when im creating a new user should i use: Dim myUser as IUser = new User?
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Dec 14, 2011
how can i import System.Windows.Forms in my asp.net class file?
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Apr 21, 2010
I'm trying to make a .dll that contains a lot of basic functionality that a program can use. Currently i am trying to use interfaces to make a lot of this functionallity independend of the program using it but i hit a snag. The Basic idea is that a programmer will create his own object using the interface discribed in my .DLL file. Then implements those functions as he likes. He can then instanciate a controller (found in the same DLL) and sends his custom object implementing the interface to that Controller. The controller can then be started and will take over all the work. I do not know what type of object is send to the controller and idealy i want to program it in such a fashion that i shouldn't care as long as the object send implements that interface.In code I am trying to achieve the following: (quite simplyfied)
.Dll:
Code:
Public Interface MyInterface '<----Decleration of the interfaceFunction GetData() As Integer
Function SetData(Data As Integer)
end interface
[code]....
this propperly. I know that the second i set the interface adaptor in the Controller VS comes nagging that it can not be converted to a "MyInterface" Class. Obviously i am doing something wrong. I can change the datatype that the controller expects to the "MyController" type but that would completely ruin the whole idea of flexibillity. I am hoping someone sees what i am trying to do and can point out where i made the thinking error.
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May 1, 2012
Class 'System.Windows.Forms.Label' cannot be indexed because it has no default property Really can't figure out why I'm getting this error... tried to google it but no success. Could anyone point out what I'm doing wrong? I'm sure it's something simple. The code in red is where the error occurs.
[Code]...
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Dec 28, 2010
Imagine that I have a System.Windows.Forms.Timer with 1000 ms interval. If I call Timer.Start() method and after 500 ms I call again Timer.Start() what happens? The second Start call will reset the interval or not? Are there any side effects?
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Aug 17, 2010
If a class is serialized and has events fired from it that are handled on a form you get the error "Form1 cannot be serialized" in c# you can use (to work around this):
[Code]....
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May 28, 2010
I'm writing a .NET CF (VBNET 2008 3.5 SP1) application, which has one master form, and it dynamically loads specific UserControls based on menu click, in a sort of framework idea. There are certain methods and properties these controls all need to work within the app. Right now I am doing this as an Interface, but this is aggravating as all get up, because some of the methods are optional, and yet I MUST implement them by the nature of interfaces.
[Code]...
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Jul 21, 2010
control which will need to be reused in several forms in my program. It basically consists of several buttons in a panel. To start with, what I need to do is get the button values from the control into a text box on the first form. But I don't want to have a method calling the textbox directly from within the control, because then it won't be reusable in my other forms. Is there something I can do in VB like parentform.textbox.append for example, where you can generically call the methods of the form in which the control appears?
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May 16, 2011
Where in VS2010 can I find a horizontal separator control, as can be found in Outlook settings (screenshots below)?[URL]..
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Jun 30, 2011
Whatever project I'm making, I always encounter a problem with a Windows Forms Timer control, I guess I just make a little mistake somewhere... So I thought I'd post it here and hopefully someone here can explain what I'm doing wrong.
[Code]....
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Jan 3, 2011
is it possible to add images to listbox control of windows forms..
if I do it anyhow using items.add method one item at a time then how to add items valuemember to items ..
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