IDE :: Declare A UserControl As MustInherit, And Then Use Its Child Classes In The Designer?
Aug 13, 2009
When attempting to create a UserControl type that must be inherited, when I try to edit one of its child classes in the Form Designer, I am not allowed to edit the child UserControl with the message:
To prevent possible data loss before loading the designer, the following errors must be resolved:
1 Error
The designer must create an instance of type "XX_ExpandContentsPanel2.IOCardMaster", but it cannot because the type is declared as abstract.
This error goes away if I remove the "MustInherit" restriction.Is there some way around this or do I just have to accept the (bonkers-mad) restriction, and not declare my class as as MustInherit, even though it's not a useful control in its own right?
i have 2 mustinherit classes where one is a generic one:
'Visual Basic 2008 - .net 3.5 - Any CPU Public MustInherit Class BaseObject
End Class
Public MustInherit Class BaseObjectList(Of T As {New, BaseObject}) Inherits List(Of T) End Class[code]...........
i receive: "Type argument BaseObject is declared 'MustInherit' and does not satisfy the 'New' constraint for the type parameter"users would never enter data in the wrong form,files they choose to open would always exist and code would never have bugs.
In VS2010, targeting Framework 4.0, I have a UserControl which contains a TableLayoutPanel with an empty second row.Is it possible to add items to this second row using the Windows Forms Designer, or do I have to do it all via code?
EDIT: In reply to Hans Passant's comment, the linked question references a UserControl being used inside another control.I am asking a question about inherited controls.I have created the following test code, where TestControl is a UserControl containing a TableLayoutPanel named "TableLayoutPanel1":
creates a control which, when viewed in the designer, contained a TableLayoutPanel named "TableLayoutPanel1" which is not designer-editable.Creating a new UserControl, not inheriting from either of the previous UserControls, and then placing a TestControl into it creates an instance of TestControl with a Designer-editable TableLayoutPanel named "TestControl1.TableLayoutPanelX".Is there any way to make the TestInheritedControl class, shown above, Designer-editable?
So I've created a very simple UserControl that is pretty much just a combo box that has US States in it and a couple properties to return the selected value as an enumeration or a string, etc.The enumeration and string values I'm using are being referenced from an external library which is working. However, when I add my user control to another project the designer-generated code has errors in it. [code] I would assume that this probably has something to do with project settings or something similar for the user control. The control itself is in a separate project and compiled as a .dll which has been added to my main project's toolbox and subsequently added to my form. [code]
I have been making a control and have added a property for a list(of CustomClass). The custom class contains a string, an image and a list of another custom class which contains a string and an image. I have added this property to the designer by adding the browsable attributes and all appears to work correctly with this.
My problem comes when running the program. I can set all of the values within the property and I can go back to them and they are saved, however, as soon as I run the program, the values are wiped out as the property is set to Nothing.In order to allow my property to be edited and saved, I realize that I must initialize the list and have done so in the accessor method of the property (if the property's value is nothing).
I have modified the values in the designer and placed a breakpoint on all of the items which use the property and it's underlying field, as well as on the property's methods itself. The first breakpoint hit is of it being accessed and the value is always nothing.
I'm not sure where the values are supposed to be stored as I have checked the designer code where it would normally store types such as strings and I have checked the resources to see if they have been saved there (like an image would be). After running the code, the values in the designer are wiped out also.
Dim proxy As USImportoerServiceTypeClient = DMRUtils.CreateAndConfigureClient() Dim request As New USDeclare_I() request.DeclareCollection = New US_ITypeDeclare() {}
[code]....
This above code do not work, becase the "US_ITypeDeclare() {}" is empty an only contains a new DeclareCollectionStructure
declare a KoeretoejErklaeringStructure to this an set this date value til "DeclareCollectionStructure.DeclareCollectionValidDate" ?
I am new to .NET with Java back ground. Got a question on name space. I believe they are synonymous to Java packages concept.If I need two classes in the same name space do I have to declare the name space in both the classes?. Both classes are in different files E.g: If Class1 and Class2 need to be in Namespace myspace. Should it be
I am using the O/R Designer to create entity classes in VB 2010. I am observing different results for different database tables that I can't explain and more importantly, can't replicate the results that I want.Using server explorer, I have dragged a number of tables on the O/R designer surface, thereby creating the entity classes.
I have saved the project and can access the various entity classes in my project code. I first noticed a difference when changes made to object instances from some tables/entity classes appeared to persist while changes made to object instances from other tables/entity classes did not persist. These object instances are created, accessed, and changed using the exact same code patterns except for the object, class and table names.
I have been looking to see if there are any differences between the way in which the entity classes are treated, either in my code, in server explorer, or in the O/R Designer. I cannot find any. The properties of the entity classes indicate that all of the classes use the runtime methods for insert, delete and update. As far as I am aware, I have not knowingly made changes to these methods.
The ONLY difference that I find is in the file NameofClass.designer.vb. This is an automatically generated document. The partial class of those objects that appear to persist changes contains different code from that of other partial classes where changes to objects do not persist.In the declarations section of this partial class, the following lines appear:
<Global.System.Data.Linq.Mapping.TableAttribute(Name:="dbo.OrderofBattle")> _ Partial Public Class OrderofBattle Implements System.ComponentModel.INotifyPropertyChanging, System.ComponentModel.INotifyPropertyChanged
[code]....
If I am right then I want to enable persistence in my other classes by causing this additional code to be generated for them. But how? why the code for this one class hase been generated differently than for all the others (actually it is this way for 2 out of about 15 classes). What setting or or selection do I have to make to enable this code to be created for my other entity classes during the automated process?
I am learningCreating LINQ to SQL Classes: Using the O/R Designer, the link is found below[url]...But when I Step #8 of Binding Controls on a Windows Form to Entity Classes says:8. Create an event handler for the Form_Load event by double-clicking the form. Add the following code to the event handler:
Note: I am working with Visual Studio 2010 Professional. Note: There are a lot of MDI Child posts, but none (that I have found) that apply to my scenario... Scenario I have an MDI form with a UserControl docked at the top. The UserControl is for navigation and is ~50 pixels in height. When I show a child form with its WindowState property already set to 'Maximized', the child form shows maximized in the MDI parent, but behind the UserControl.
in VS 2008, is there a way to design a ContextMenuStrip in a designer without a relation to a specific Form or UserControl class? For example,if you need the same ContextMenuStrip in Form1, Form2 and Form3, in which of them am I to design the ContextMenuStrip? Do I have to add a "pseudo-Form" to the project that contains my shared ContextMenuStrips and create only one instance of that Form, or is there another way? I consider this a programmatic hack, that's why my question is whether the IDE offers something better.
I am making a TabStrip control to hold a number of tabs just like TabControl, but only with the tabs, no page. The control has a "Tabs Collection", which stores a list of "Tab" class. "Tab" is not inherited from Control, but each tab has its events. So when the user add a "Tab" in the "Tabs Collection", each "Tab" instance should have a (Name) identifier, which user can access it in the code, and with WithEvents keyword so users can add event handlers to each "Tab". The expected out come should similar to this:
Friend TabStrip1 As TabStrip Friend WithEvents t1 As Tab ... Me.TabStrip1.Tabs.Add(t1)
I have been developing some components for our products at work, and one of them is based off the flow layout panel.What i would like to do is provide a custom designer for it, but without loosing the features provided by it's default designer (System.Windows.Forms.Design.FlowLayoutPanelDesigner) which is marked as internal.Using Reflector i thought i would just implement it again myself, seeing as it inherits from 'FlowPanelDesigner and that from PanelDesigner` all of which are internal.
Why would these classes be specifically marked as internal? Is it due to them being specifically for Visual Studio use, and thus not 'framework' code?Also, is there an easier option that re-implementing all the functionality?
Currently I declare my main class on frmMain. as public MyClass as new clsMyClass Thus anywhere in the application I would address it as: frmMain.MyClass.Function(MyParam) This does not look as neat as I would like it. Where can I load this Class so that I can address it as: MyClass.Function(MyParam) from anywhere inside the application.
I have a nested class, let's call it class1 and it has class2 inside it; VB.Net eg:[code]
1) How can I define X number of Class2 objects[let's call it: Node(x) array]** with NEW() subroutine called?' this raises error: dim cls2(n) as new class2 end sub.
2) How can I return actual number of Node() array? [code]Outside my class in main project I define cls1 object:[code]Now an array of class2 is created inside cls1.
3) Now,How can I access All of them[node(x) array which is created inside cls1] with all properties and methods available?
I remember I wrote a ProcessManager class with this functionality in .net 2003, nearly 4 years age, I don't have the code now.
I'm having a bit of trouble with creating one of my custom controls. What I've got is a listbox within a usercontrol, and I need to be able to click on the lists items while still in the designer. This would make it act much like the tabcontrol.
I have been developing an application for quite some time now. I have decided to create an mdi parent form to hold all the windows I have done so far. Is there an easy way to implement the mdi parent/ child associations rather than to go and declare them each one individually.
I have a program with a base class and classes that inherit the base. A Windows Form will call a function of each child class which raises an event from the base class. The function call to the first child class works fine: the event is raised for the first child class.
I have a Clients master object and then a number of child objects whose exact number is not known in advance such as Client-Contacts, Client-Payments etc, all of which have a one-to-many relationship with the Client master object.How do I define classes for such a scenario? Do I for instance create the master Clients class and can then I create an array of class somehow for child objects?
I have two Parser classes that inherit from a base class, BaseParser. I want to use either class as a parameter in another Monitor class. The Parser classes, CS600 and TCH600, both have two properties, RawDataList and SummaryDataList. The CS600 class's RawDataList returns a List(of CS600Data); the TCH600 RawDataList returns a List(of TCH600Data). The SummaryDataList returns similar classes in each Parser class. CS600Data and TCH600Data derive from a base class, BaseData.BaseParser also has RawDataList (List(of BaseData)) and SummaryDataList (List(of BaseSummaryData))The Monitor class has a private field, _thisParser which can be either of the two concrete Parsers above. I want to be able to call and use RawDataList and SummaryDataList of _thisParser within Monitor class, but when I construct the concrete Parser classes, Visual Studio notes that the RawDataList property of CS600 cannot override the RawDataList property of the BaseParser because they differ in their return types.
I thought that since CS600Data derived from BaseData (but also adds some new properties of its own) that I could use CS600Data wherever I use BaseData. What am I misunderstanding? How can I correctly construct these classes?
Public MustInherit Class BaseParser Protected _rawDataList As List(Of RawGasData.BaseData) Public MustOverride ReadOnly Property RawDataList() As List(Of RawGasData.BaseData)
I have created a custom UserControl, with a custom designer, which contains a Panel which is editable. Any controls dropped onto this Panel will go off-form when an Anchor is set. This was already reported here and acknowledged as a bug:[URL].. Are there any known workarounds? Or available hotfixes for this issue?
I already implemented ISupportInitialize in my custom panel class, where i set the docking, which doesn't help. Here's the relevant code:
I'm looking at a VB.NET class (that I didn't write) that is declared "MustInherit" (abstract in C#, I believe) that has three methods, all of which are defined as "shared" (static in C#). There are no properties or fields in the class - only the three methods. From an OO perspective, does this make any sense?
My thinking is no, because by making it MustInherit, you're essentially saying you can't create an instance of this class - you must inherit from it and create an instance of the derived class. But since all the methods are shared, you'll never actually create an instance of the parent class anyway, so the "MustInherit" does no good. You might as well not mark it MustInherit and just inherit from it whenever you want.
At the moment I'm trying to create a kind of model in vb.net which can be used to create/fetch database entrys.
I created a main class Model with a shared function to fetch the datasets, e.g. Model.find(). Now I'd like to create Classes which inherit the main Model-Class, e.g. a separate one for users: UserModel.find() => "SELECT * FROM users".
What I need now is to find a way to tell the Class which table it should use. I thought about an abstract String "table" which is a constant in each "child-model", but how could this be implemented as it's not possible to override shared members?
Edit: Maybe this will make it a little clearer what I mean:
Public Class Model Public Shared _controller As Controller Public Shared table As String
[Code].....
So I want a shared method which finds all database entries and gives back an array of instances of its own type, e.g. Model(). That's why I wanted to keep the find-method shared and not bound to an instance.
I've got an Interface that dictates classes that implement it to use a large amount of properties and a few methods. I've been using this interface for some time and I have a large amount of classes that implement it.
Now, I need the interface to become a MustInherit (abstract) class, because I need to implement a single method that must be the same for every class implementing the interface (I mean the implementation must be the same, hence I cannot use an interface anymore).
Is there a way to do this automatically, perhaps even using third party tools such as resharper (which is C# only I think?) or similar? I get a headache even thinking about the work I need to do to make this change manually[code]....
