I am trying to broaden my knowledge of user controls or to be more specific, composite user controls. Msdn has a walkthrough on the subject here which although not in VB is easy enough to follow and get results.
What I had had in mind was to create a base user control comprised of a split panel, one half of which would be used to display dynamic help and the other half which could house whatever controls the new user control which would inherit from this required. The problem that I am facing is that when I then create a new inherited control based upon my base control I cannot add new controls to the design surface. If I don't have a split panel filling the entire design surface of the base control I can add new controls, but if I do I can't.
Either I am doing something wrong, or more likely failing to do something on the base control that I ought to do , or this can't be done which I find odd to believe. I'm hoping someone can explain what it is I've missed.
This is being targeted at winforms with vb.
Thanks
Well, Did you make the split panel's modifier to protected or protected internal or public? That should do the trick.
By default it is private and so designer will prevent you from accessing it.
Related
Like many, I'm trying to build a wizard like presentation.
I've created a Windows Form as the host for a series of "WizPanel"s that have been designed as User Control Forms. Each of them may/will have unique data connections and layouts. My intended implementation creates a Collection(of UserControl). I'm at the design point that I want to load the collection with a set of panels that best describe the process flow required by the current use case.
The problem I'm running into is how to be able to load a New UCDataReview (user control form), a New UCDataParameters (user control form), then the rest of the panels as required. I don't want the panels to load data at this point as some of the data queries may never be required - based on data supplied in previous panels (possibly, just design at this point). I just want to make sure data only loads when I specify. I like to have a function ShowData() on each of the panels and then execute it from within the main Wizard form (after the next button is clicked - it wouldn't be needed on a back as it should be there already).
So, I'm stuck on the concept of crating a 'base wizard panel' control (WizPanelBase) that has a ShowData() function that is empty in the base control form but can be overridden in the class (WizPanel) that the panel is based upon. I'd then have a Collection(of WizPanelBase) that would then allow me to issue a ShowData() call.
I'm sorry for not using the correct verbiage as I'm only a part timer and just playing to learn. I've done this with an Object Class (ObjBase_Person; ObjBase_Vehicle ...) and then extended them into Person_Student, Person_Instructor, Vehicle_Car, Vehicle_Truck etc). I'm quite sure I can, I just know enough to be dangerous, but I don't know what to even ask for to find tutorials. The similar questions here are generally about using a User Control on a Windows form.
To illustrate what I'm asking, let's say I have a custom TextBox that has 2 modes. Mode 1 only allows numbers, and mode 2 only allows dates in a particular format.
Using a class module I can create this custom TextBox, and I can use a loop when the userform initialises to set which TextBoxes are custom.
What I'd like to happen is have the custom TextBox, or what ever custom control I want, show up in the toolbox. And I also want its custom properties, if they exist, to show up in the property window.
So far, I've been unable to find a way to do this. In fact, I've been unable to find out if it's even possible. It seems, to me anyway, that it's something that should be possible, but maybe I'm barking up the wrong tree. If it's possible I'd really appreciate being pointed to a resource.
Setup:
I have created a Form that I wish to have serve as the base from which I will inherit other forms. This base form serves as a "template" of sorts, but it also provides a good deal of functionality related to the structure, as well as the interrelation of all of the controls provided.
A primer for the images that follow... The top info-colored bar is a custom control inherited from ToolStrip. The bottom strip is another custom, again inherited from ToolStrip. The left white block is a TreeView and the right block is a TabControl (having deleted all TabPages from it...I intend for these to be added in the inherited forms).
Image of base form in designer:
Image of inherited form in designer:
Clearly, the only difference is that when I open the inherited form, I get a little box icon superimposed over each control, and when I click them, I get the padlock telling me I cannot edit.
The problems:
All controls on the inherited form are locked. I have researched the issue of visual inheritance, and as far as I can tell, I'm not using any controls that expressly do not support it, as this link suggests there are. In this Q&A, Hans suggests changing the modifier on those controls, which I have done. In fact, I tried both Public and Protected, all to no good result.
I am stumped.
This is a technical restriction in the designer, it is specific to the SplitContainer control you are using. And some other ones. The trouble-maker is the ISupportInitialize interface.
Controls use this interface when they can't afford the properties of the control to be assigned in an arbitrary order. The designer helps when it sees that the control implements this interface, it calls the BeginInit() method when it starts assigning properties, EndInit() when it is done. The control uses these methods to delay the side-effect of property assignments, the EndInit() method makes them effective. Important for SplitContainer, the minimum sizes of the panels also affect the splitter position.
Perhaps you can see the rub, the InitializeComponent() method in the base form class has already called ISupportInitialize.EndInit(). So modifying properties again in the derived form class is unlikely to turn out well. The designer protects the control from this by locking it.
Very inconvenient, there is no simple workaround. If modifying the SplitContainer in the derived form class is a hard requirement then you'll have to give up on inheriting it or write the code by hand in the derived class constructor.
How do I set a number in a up/down box then press a button to show me a second form with the amount of fields (like labels with text boxes) defined in the up/down box? I'm new to programming so try to explain in really simple terms if you can. Thanks
Code based solution you can implement now
Container controls in VB.Net inherit usually inherit from Panel control which owns a collection by name Children.
You can add dynamically created controls to this collection to create the second form.
Complex but technically sound solution
Invest sometime to learn XAML and create XAML templates to this job for you. Refer the link here which solves same problem in C#.
I am new to Visual Basic and trying to get around in developing a good gui for a chat interface. I can understand the language as i have been using php and java from quite sometime.
Requirement
Basically i am trying to develop a interface which will show a list of users and along with that display a status (online/offline). My users will reside in mysql database. On clicking the user i want some actions to happen.
Question
I see there is datagrid, listview,listbox but not sure which one to use. Also is it a good idea to display the users by directly quering the mysql database or by accessing a php script which runs few queries and gives the data?
The ListBox control would not be a great option since it doesn't easily support multiple columns. The ListView control in Details view is a great option. I think it looks and works nicer than a DataGrid, but it doesn't natively support multi-line items. If you need multi-line items, the DataGrid control may be your best choice. Another option, which would give you more flexibility, would be to use a LayoutPanel control to display a vertical list of your own UserControl. You could design the UserControl anyway you want meaning you could fully control the size, look, and layout of each item in the list without being constrained by the list control.
As far as getting the data, that depends. If the database is always on the LAN and performance is important, then each client should go directly to the database. Otherwise, getting the data from a php script, web service, or WCF service would be a much better choice.
Rather than using the TableLayoutPanel, I would recommend using the FlowLayoutPanel with the FlowDirection property to TopDown and the AutoScroll property set to True. Then, to add a control dynamically, you could do something like this:
Dim item As New MyUserControl()
' Set properties of user control
FlowLayouPanel1.Controls.Add(item)