I have a base form and I inherit other forms from it. However, if i go back and change say the size of the base form, I don't see those changes take effect in my inherited forms. Does anyone know why that is? Is there a solution to this issue?So as far as design is goes, what exactly gets inherited by other forms?
View 9 RepliesI have a form called BaseReportForm that handles drawing some stuff to in a panel to create a template for a bunch of reports. The drawing all takes place in the Panel's Paint event and this form will always be inherited. In the inherited forms, I draw the specific details of the report in the inherited form's Panel Paint event. So I am drawing to the same panel from the base form and from the inherited form. It all works fine, but when I try to open the design view for the inherited forms, I get the following error..
Quote:
The event Paint is read-only and cannot be changed.
I'm not sure I am handling my paint events correctly. Is there a different way I should be handling the drawing of these reports?
I have setup some base forms with some bottons on it The buttons are situated in a panel.Both the panel and the buttons modifer properties have been set up as "Friend".The problem I have is when I inherit these base forms, the buttons seem to jump around by themselves allot
View 6 RepliesWhen I create an inherited form, after creation for some reason I cant see the form to edit in designer, I mean I cant drag and drop buttons, labels or any control to it since I just CANT see it, I have included a pic of what I see below where Form1 is the Inherited Form. What Am I doing wrong or what is happening
View 6 RepliesWe have a vb.net 2010 application with a base form and an inherited form When we change the position of a control coded on the inherited form we lose handles on the events in the inherited form for that control. We also lose the handles on the Load event in the inherited form.
View 9 RepliesThe program below trhows an error in the line "mTable2 = mTable.Copy". The error is: "Unable to cast object of type 'System.Data.DataTable' to type InherintanceQuestion.InheritedTable". This is because mTables is an instance of the InheritedTable class which inherits a DataTable and mTable is a DataTable. So, is there any way I can create the mTable2 to the mTable.copy to the mTable.
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[code].....
I have a project that has mainly two objects, both inheriting from a base. Like this:
Public Class Vehicle
Property Model As String
Property Make As String[code].....
The above function doesn't work because myVehicle is a Vehicle, not a Truck.Is there a way I can pass around a Vehicle type and have the IDE know which type to use? Or am I completely missing a better way to do this?
If I defined a ENUM in a base object with serveral default values. When I inherit from the base object I want to add more options the the ENUM list which are specific to the inheriting object.
For example my base could have a ENUM called Direction with values:
None
ALL
Stop
Start
I create a new class call Compass which inherits the base class and what to add the following to the ENUM Direction. I create a new class call Navigation which inherits the base class and what to add the following to the ENUM Direction. So, In my inheriting class haow do I extend the ENUM.
i've finally got round to learning about classes and inheritance, but i'm not sure how to proceed. i have a base class Employee, which is inherited by 2 derived classes. how do i use the same Employee class in both derived classes? obviously if i write a sub new for both of them + declare a new Employee class, they won't be using the same class. heres my Employee class:
[Code]....
In re-engineering a windows forms application, I find that a lot of code-behind in the various form classes is duplicative and I'm trying to centralize as many procedures as possible into a base class which can be inherited and used by the subclassed forms.
This process seems to be going well and is making the code in my subclasses much simpler and hopefully easier to maintain, but I'm not sure where to draw the line between leaving code in the subclasses and engineering for generic resusability and moving it to the base class.
Specifically, in some subclasses I have code which manipulates variables and objects specific to the subclass, and although I could move the code-behind into the base class, the base class code references specific objects which are needed to compile. For example, each subclass manipulates a databound datagridview and form detail controls which allows the user to select between multi-record and detailed single-record views of a datatable.
In Visual Basic 2008 do I need to declare dummy data objects in the base class so that the base class will compile? Or is there a way to indicate that the data objects will be provided by the subclass?
Suppose I have piece of code like this:
Public Interface ISomething
....
End Interface
[code]....
I suspect I am being very silly here but I have the following setup
Class MustInherit myBaseClass
'some stuff
End Class
Class myInheritedClassA
[code]....
Running this results in the following error
Unhandled Exception: System.InvalidOperationException:
There was an error generating the XML document. --->
System.InvalidOperationException:
[code]....
is there any way of 'Widening' the inherited class to the base class so this would work?
EDIT:regarding XmlInclude(typeof inheritedClass), currently this method could potentially return a number of types of inherited class (i.e myInheritedClassA and myInheritedClassB) is it case of simply having to add each of the inheritedTypes in this tag?
I understand that inherited classes can't be converted from base classes. But is there any way to write a conversion sub, so that the base class gets assigned to MyBase, then extra properties are added?[code]...
View 7 RepliesI am having a problem with closing a form which I have inherited I have a form called frmAddForm_Simple, which contains 4 main controls (A Data Grid, A Save Button, A Close Button and a Text Box). The idea around the form is to create a form which could be used for inputting of many different types of data which are all entered in the same way (i.e. to add a new row to a database for [Status] table or [Location] table, all of which contain 2 columns in the database (an [Id] and a [value]). On the form I have a property called _FormChanged, which when the textbox text changes, sets the property to True. I then have the following code on the Close Button:-
Public Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
If _FormChanged Then
If MessageBox.Show("Are you sure you want to close and discard any changes?", "Discard Changes",
[CODE]...
Is opened as a dialog (ShowDialog) and when I go to close the inherited form (by click on btnClose) and answer No to the above MessageBox the form closes anyway. Using the Debugged I have worked out that the following events occur in sequence (all of which runs in the Master Form mentioned above):-
1) btnClose_Click sub Routine runs
2) I answer No to the question do I want to close the form
3) The debugger steps over the Me.Close() line (as expected)
4) The debugger jumps up to the Sub Initialise (where ShowDialog was called from) and closes the form.
So at no point has the debugger even ran a line of code which reads Me.Close(), but the form closes anyway so Im fairly confused as to why the form should close.
My Master Form (frmAddForm_Simple) Code:-
Public Class frmAddForm_Simple
Private _FormChanged As Boolean = False
Private _FormLoading As Boolean = False
[CODE].............................
I am trying to create an inherited form- when I go to add it, I get the following message- "CustomerInformation --- The base class 'Object' could not be loaded. Ensure the assembly has been referenced and that all projects have been built"
View 3 RepliesI'm currently working on binding an objects properties to fields on a Form. Whilst I have managed to get it so that I can get standard objects to bind, I am having a problem figuring out how I would go about binding an inherited object.
For example, if I had a Client class (the parent class) and then two sub-classes called CompanyClient and IndividualClient. The CompanyClient would have an extra field company name for example.The problem I'm having is that I'm not certain how to set up the binding, as if I set up the binding against the Client class then I would be missing the Company Name property for the CompanyClient, if I set up against the CompanyClient, then it wouldn't work with the IndividualClient as it doesn't have all the fields.
I know I could get around this by having different forms for each of the different Client types, but as almost all of the properties are the same I would like to avoid this if I can.I was wondering whether anyone knows how I might be able to go about doing this
I have a an inherited form that has a panel control on it. I want to paste other controls onto this panel but the paste option is grayed out and won't let me do it. I made sure that the template form did not lock the panel. I'm stymied from making progress until I can get this resolved.
View 2 RepliesMainForm having a few buttons, VolForm is inheriting MainForm. I can see this perfectly in the designer.VolForm itself contains a trackbar. Now have 2 forms. Form1 and Form2 both inherit VolForm. If I change the trackbar from Form1, and then show Form2, the trackbar is not having the same value. Is there any way to keep this trackbar the same in every form that inherits VolForm?
View 2 RepliesUnable to add Controls to Inherited Form I should be able to add an inherited form by simply[code]...
View 2 RepliesI'm trying to create my own control to build a custom planning on it.After trying it with loose controls I got an error but after advice on my previous post, I redraw everything.I have now the header of the control finished, the header shows the days of the month for as many months that fit in the window.Now I want to put the list of data below it, but it will be more than the windows height, so I need to have a scroll bar that will scroll the data but not the header.I would not like to design my own scrollbar and rather use the scrollbar control for it, but when I put it in, I cannot use the NEW keyword.example:
Dim sb
As
ScrollBar
with this I get the error message: 'New' cannot be used on a class that is declared 'MustInherit'.How can I get a scrollbar on my form to scroll the list only (so not the header)?
This might seem like an odd question, but is there a way to make it so that any form that is created based on another, would have some comments in the code behind of the new form?
For example, i create a form called frmONE, and i put in code like this:
Overridable Sub frmONE_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Make sure you call these functions, in this order:
[Code]....
bare with me during this silly example. :-) Let's say I have a class like this:
Public Class Animal
Public iLegs as int32 ' Number of legs
Public bWings as Boolean ' Wings? Yes/No
End Class
And another class that inherits the "Animal" class and adds one more property:
Public Class ScaryAnimal
Inherits Animal
Public iScariness as int32 ' 0-100, how scary is it?
End Class
Now, if I have an instance of "Animal" with some values in it, and I decide I want to cast it to a ScaryAnimal for some reason, how do I do that without having to create a new instance of "ScaryAnimal" and copy each property value?Basically I'm looking for a way to do this, without having to write the lines marked with '*** below:
[Code]...
Pretending I have a class that inherits off Control, how would I handle the parent form's Resize and Move events within the control? I have a painting glitch that happens when the form is resized or moved. Right now in the form I just have:
vb.net Private Sub frmMain_ResizeMove(ByVal sender As Object, ByVal e As System.EventArgs) _ Handles Me.Resize, Me.Move Me.Refresh()End Sub
But this can't be the proper way to do it, considering Refresh() invalidates all children (will be slow and flashing if the form has lots of controls). I want to basically do the above code inside the control.
Edit:This is the glitch after a resize of the parent form:
And this is what the button is supposed to look like:
Also, I experience this issue if something like a message box is dragged over top of it. How can I remedy these issues by forcing a repaint?
I have a base form and I am trying to get the DataSource of the ActiveControl if the control is a datagridview.What I have so far is:
Dim curControl As Control = Me.ActiveControl
Dim ControlType As String = curControl.GetType.ToString()
If ControlType = "System.Windows.Forms.DataGridView" Then
[code].....
I am migrating my code from vb.net 1.1 framework to vb.net 3.5In my windows application, the base window has some buttons and events are written for the same.I have shortcuts defined for these buttons also, for example: ctrl+d, DEL (keyboard) etc.Now i open a property Grid form on top of my base window for a selected object.Even when the focus is on this property grid, i am noticing that my base window events are firing on pressing those shortcuts.
example:I select some text in my property grid and hit delete button from keyboard. The delete event that i have written for the selected object gets fired and the text is not deleting.I fail to understand why is it happening. It wasnt behaving like this in .net 1.1.In .net 1.1 it would delete the text and only when the focus is back on the base window, hitting Delete would call the event.How do i control such a behavior? Is there some property that i need to set for property grid in .net 3.5 to prevent base window events from firing till the time focus is on property grid form?
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?
When I try to add an inherited form, I get an error:
"Value does not fall within the expected range"
(Add-->New Item-->Windows Forms-->Inherited Form), I get the "Add New Item Project Name" window. When I click the Add button, I get the error.
on the custom inherited control i created, i noticed that when i bind my custom property to a data column, if that data column returns a value other than Null it always return a datarowstate of modified even if there were no changes. to produce this issue, i have below a sample code for a test inherited control
Imports System.Windows.Forms
Imports System.ComponentModel
Public Class TestControl
[code].....
I have two classes[code]...
How can I modify class1 in a sub in class2?
I'm confused regarding the MS examples for inheriting a treenode. I have created the following class to allow an addtion description field on the treenode:-
[Code]...