I have an application made in winform using C++ (developed in VS 2010). The GUIs have certain text fields, radio button, check boxes etc. To operate the software one has to fill in these fields/buttons/boxes etc.
There are roughly such 50 different GUIs, having roughly 20 fields in each one.
I want that after the application is closed, and restarted, most recent parameters in this fields automatically fill in, so the user do not need to re-enter all those values again.
What is the easiest and simplest way to achieve this?
This is best solved using MVC pattern where the Model contains the data that was filled. The view contains the way it will be presented(such as in Winforms) And lastly the controller which besides doing business logic will need to do some work (for saving the state).
I prefer using serialization for this. You can serialize the model fields and read them back(fields that are necessary only).
If you don't like serialization you can try writing to INI files that will be easy to modify.
Thirdly you can use a database mdf file to store the state.
But to do all this well you will need to modify the App to use MVC architecture.
You can use the Windows Registry with
WindowsFormName (subkey)
---------> ControlName (subkey)
-----------------> ControlValue (subkey)
When the Form is Closing you save the values for each control in the Registry
When the Form is Loading you read the values
If you are satisfied with a quick and dirty solution you can try this:
Implement a save mechanism:
Iterate to all the form controls (recursively if there are panels or
other containers)
If the control is edit (or other type that holds
data) save the control text together with his name
Store the name,
value pairs (INI file for example)
Implement a load mechanism. This assumes that there are no dependencies between values (If there are automated computed fields do not save them)
Load the values from the storage (if you choose files the file name can be the form name)
iterate to all the form controls and if you find its name in loaded data set the value
Once implemented this approach can be used for all the forms and it will cope with adding/removing controls. However if there are business rules maybe is better to use a MVC approach and serialize the model.
Related
I am planning a new desktop application. It will provide a WYSIWYG editor for HL7
files (OSS Project). HL7 is a structured file format often used by hospitals for
exchanging data between systems.
The basic structure of the format comprises of records which are \r
delimited. A record can have N fields which are | delimited. A field itself
can be sub-devided into components ^ and sub-components & and
fields can be repeated ~ (similar to an array). Every message type has a
different number of fields/components and sub-components. Empty fields at the
end of a record can be omitted.
Example of a simple record:
OBX|14|NM|0050–5^Calcium||8.9|mg/dl|8.4–10.4||||F
I have already implemented an efficient parser which turns a whole file into a
hirarchial data structure in C. I want to implement an application that
allows editing these files like in a text editor. I want to keep the underlaying
hirarchial datastructure at any point, so it is easy to validate structure and
content of every field, upon user changes, quickly.
Also note worthy is, that I already implemented a viewer where the document
strcuture is displayed in a QTreeView. The structure is using a QAbstractItemModel.
Now to my actual question: how would I approach the problem of having a text editor
with a structured data model in Qt. I have done some research:
there is a QDomDocument, it seems to be made to work with xml data. I could convert my structure into XML but can the dom object be used with a text editor ?
Is there a way to bind a tree like document model to QTextEdit or QPlainTextEdit?
is it possible to bind a QAbstractItemModel to a document in QTextEdit or QPlainTextEdit?
What would be the best approach to tackle the problem of having a textual representation of a tree that gets updated once text and/or stricture is changed by editing in the text field?
Performance and cross platform capability is important, so this project will be implemented in C++.
Thanks for any advice and examples appreciated if you have any.
-S
I may be bordering on a discussion type question here so I apologise if the question is not specific enough.
I would like to know if I my current application design is inherently weak/flawed. My background is C so I am not using clever c++ patterns to their fullest extent, of this I am sure.
My application is similar to a 3D modelling package, without geometry creation (e.g setting up animations using existing models). The user imports a geometry and can set various parameters on pre existing geometry, and there are time dependent values that relate to the whole system. The output is a text file to be processed by another application.
I am using a QTreeview to render a QStandardItemModel. I simply store pointers to my core classes in the model's items. These have specific UI for each class type, and are all descended from a common base class. They all have a QWidget which is their "mainwidget"
When the user clicks on part of the treeview, the stored class is retrieved and its mainwidget is displayed on a pane on the UI. So - treeview on the left, pane to the right with the current item's contents, and a 3D view showing the geometry.
Most of my data is stored in the classes UI elements themselves; I don't have a central database which stores anything, and when it's time to save the project, I traverse the tree and let every item write itself to a QSettings file. This feels quite naive but it does work, and the reverse happens on project load. The project class generates new classes based on the type information in the settings file and they then read the contents out of the file themselves.
Similarly when writing the output file, each item knows how to write itself and does so. Where other classes can influence the output of others (for example, start and end times), higher level classes process the children and will set start and end times based on the order and duration of each child.
Should I be storing more data in the QStandardItemModel itself, or defining my own model perhaps? Does it sound like I have set myself up for future problems?
At the moment I have modified this system a couple of times to provide customised applications, but I am about to try and make it more generic. I welcome suggestions for improving my design. Go easy, please!
You should try to avoid creating god objects. Split your tasks and duties into smaller chunks. It makes it much easier to maintain and also much easier to extend if you need to.
Your specific use-case would benefit a lot from a more complete use of the Model-View-Controller pattern.
What doesn't make sense in your design is that your data objects hold a UI element. Since only one item can be shown in the right pane, this seems like a waste of resources. It makes more sense to have a single object that then gets passed a data object to display.
What I suggest for your program is the following:
Splitting your data into classes that only have functions for reporting and modifying values. There should be no knowledge of how to display data or store to a file.
Create separate class that handles the reading and writing from a file. If your model is very simple, you could just use single functions to do this using the method shown in the documentation for QDataStream or QTextStream.
Use your QTreeView and QStandardItemModel as Adaptor class between your data objects and the left pannel.
Create a controller class that gets informed by the QTreeView if data needs to be displayed in the right panel. The controller will then retrieve the data item and pass it to the right panel in order to be displayed.
The right panel should act like another View class with the sole responsibility of graphically displaying the data passed in from the controller class.
One advantage of doing it this way is that, if there are different categories of data that get displayed differently in the right panel, the controller could examine the selected data item, determine what the category is, create a view widget to put in the right panel, and then pass it the data to display.
This pattern is open-ended as far as extendability is concerned because you do not need to change your data classes if you need a new display, you merely need to create a new right-panel widget, and then teach your controller class how to determine when the new view should be used.
Another advantage of this pattern is that you only ever need to have a single widget created to display data in your right panel. If you change your selected item, you can just pass it to the view class that already exists and get it to refresh its display with the newly selected data. You only need to distroy the right-panel view widget if a different category of data object is selected and its data needs to be drawn in a different way. The controller class can determine whether a right-panel view widget can be re-used or whether it needs to be swapped out for a different widget.
I am trying to utilize the Model/View architecture to accomplish my goal but I am unsure as to whether this is the proper tool to use for this task.
I have a Material System I have been using, which I more recently have created an editor for using Qt, it uses a QGraphicsView to display items which are interconnected to form a final fragment shader code, this works extremely well however, I am having difficulties finding a way to display these custom data structures without hand coding widgets for each type of item.
These custom data structures are simply classes with members which I wish to modify using an interface depending on each members type. For instance if the item is a Value which in my material system represents a single variable, like a texture, I would like to be able to have 2 editable areas, one for the texture's path on disk, and one for the name of the variable.
What is the best approach for interpreting custom structures like this and creating widgets based on their type, and then mapping those widgets to edit/display them. All the google searching I found led me to the Model/View architecture however it seems this is more made for things like SQL databases and XML files.
class Value
{
std::string m_strType, m_strName, m_strValue, m_strLocation;
};
It sounds like you're looking for something like the Property Browser Framework. In short, you'll make all of the members you want to edit properties, and then use the property browser framework to create a model that you can then attach a view to.
I would like to dynamically build a form to edit a set of properties (say from a xml file or so).
On top of that, I would like to perform validation for each property (mandatory values/optional values) with a set of rules (ideally also dynamically loaded).
These rules could be associated to a single field (allowed values, range, ...) but could also link several fields (conditional validation).
I would like to be able to save the results "on the fly" (as soon as a field loses focus).
Does someone have a good lead to get me started?
Here is what I found so far:
I could start from the Qt property browser framework for the dynamic form generation. I could extend this framework to suit my needs.
Regarding the validation, I read about QValidator which seems to be a good start. However, I couldn't find anything involving several fields (cross-parameter validation)
The QSettings framework does this auto-save feature quite nicely and I guess I could reuse that.
I just wanted to be sure I am not missing some existing framework to deal with my goals since
it seems like a relatively standard thing to do.
Assuming that the fields of the form are fixed. Then you could use a shared instance of a QValidatorto validate the text in all the fields by running your validaton over a list /dictionary /map containing pointers to the fields. The list/*dictionary*/map will have to by dynamically populated and cleared, and a pointer to it hard-coded inside QValidate::validate. And if QValidator sharing is not allowed you will have to create individual ones and execute your cross-field validation.
Alternatively, you could use Qt's Signal-Slot mechanism to implement your validation whenever the text in your field is changed.
I had no idea of QSetting, and would have used the very same signal-slot mechanism to do the autosave.
I was wondering what would be the correct method for saving all user data for an application I am working on. The application is in QT. The user inputs a lot of data into the application and the data will be different for every user. I want the ability for the user to save all the current data to a file that can be user by the loaded by the application again once the user wants to use it again or use it on another computer running the application.
What would be the correct and best way to do this? Do I need to use xml format? And then use the xmlreader for QT? Or do I just need to create my own file format and just use the stream to just read everything in. The data in the file will need to be labeled, because it will need to put the data in certain spots on the gui. And the user has the option to dynamically create boxes and tabs that hold certain information.
If you need any more information, please let me know.
A short example:
I am not only reading gui locations.
But the contents of those. For
instance. The user is able to create
tabs that contain edit text boxes. And
those tabs are associated with items
that are in a list. When the user
clicks on an item in the list the user
will be presented with a whole set of
new tabs. And each tab has some
editing forms. The file will need to
contain what is in the list, what tabs
the user has created under each item
in that list and the contents of each
tab associated with the tab of each
item in the list.
In essense, yes you'll be creating your own file format, but the actual content can just be XML in whatever scheme you need. Then you can use Qt's built-in XML processing capabilities to pull the heavy lifting of parsing the text (I personally prefer the DOM model, so I use QDomDocument as my base point), and you'll just need to worry about parsing things to and from the individual nodes.
The Qt framework has some great XML samples if I remember correctly that helped me get off the ground almost immediately. Hope they help!
Another great solution is to use internal database implementation (QSQL on top of sqlite). Compared to the xml solution, it might be more versatile (update when needed, can use external keys). Qt has some rgeat examples about using it aas well.
In terms of dependencies, XML solution will require you to use xml and xmlpatterns (if you want to validate stuff), whereas sqlite solution will require QSQL + sqlite plugin. I think that sqlite guarantees atomicity of writing , thus preventing corruption of data (think : the user is killing the app while it's saving).