Protecting custom inline elements in WPF RichTextBox - wpf

I'm currently spiking with the WPF RichTextBox before I decide whether or not it can be used in a project of mine.
What I need is to have elements of text representing various objects (other texts or objects), a bit like a WIKI but not quite. Clicking on such a text will make stuff happen, like navigating to other texts or providing additional options.
Anyway, as these little text bits represent other objects I would like to protect them but I have succeeded with this only in part: The user cannot position a caret inside such a text element and edit/delete it but it is still possible to make a selection and delete/replace it, including my custom elements.
Have anyone travelled down this road with the RichTextBox? My latest experiment was to simply record all custom text elements when being part of a selection and then restoring them after the (destructive) edit. That fell apart because I can't find a way to re-insert my custom inline elements (derived from the Run class). The only way I've found to programmatically insert a Run (based) element at a specified position (TextPosition) is via its constructor.
Well, any hints would be greatly appreciated.

You are really looking for a FlowDocument, not a RichTextBox.

Related

Benefits of Custom WPF Controls

I've thoroughly checked the custom controls topic, spent several hours looking into custom controls written by other people. I've written my own custom button, to feel it better. I've read all the google answers around the "why custom controls", "advanced custom controls examples" and such.
My question is, WHY?
Why would I (or anybody) go through 9 circles of hell to create his own custom control, when one can just adjust an existing control to his needs (using styles and templates). I actually didn't find any explanation on google, just tons of examples, mostly from people who sound even less educated than me.
I imagine there IS such need, when talking about some complicated DataGrid with, I don't know, every cell being a button or something (and still I believe I could do it with a regular DataGrid)... But I've not found anything more complex than a beautiful button. Is there nobody sharing a complicated code on the topic?
There are different levels of element customization in WPF, depending what class you extend from. Each has its own uses and is implemented differently. It is not clear from your question if you are asking about a specific type of control or about all of them in general. So, I will tell you what I think about different ones.
UIElement or FrameworkElement
Extending UIElement gives you the lowest level custom control where you have complete control over the layout and rendering. FrameworkElement is slightly higher level as it does most of the common layout stuff for you while also allowing you to override key parts of it. The main idea with these is that they do their own rendering rather than composing other elements together.
I have made a number of custom FrameworkElements over the years. One example is a ruler similar to one you might find in a program like Photoshop. It has a bunch of properties providing customization for how it is displayed as well as showing markers indicating mouse position relative to the ruler (and a number of other little optional features). I have used it in two different professional projects. I think the main benefit is that it is extremely easy to drop in and set properties/bindings on wherever desired. Build it once, use it over and over.
Control
Extending Control introduces the concept of compositing multiple elements/controls into one reusable component via control templates.
I have used this one less often, but still find it very valuable in the right circumstances. Again, the main benefit here is reusability. You create a control with properties that make sense for what you want to do, then hook up those properties to the properties of the controls in it's control template. Really, this is the same as applying a new template to an existing control, with the added feature of being able to define your own dependency properties. You also have the ability to perform custom logic in the control's code if you need to.
I may be misreading some of your text, but you seem to imply that making a custom control is considerably more difficult than making a control template for an existing control. I have found that the two are nearly identical in most cases using this approach, the only difference being whether you have a code behind you can use.
User Control
A user control is really only slightly different from a custom control practically speaking. Only, instead of defining a control template, you define the visual content directly.
This is probably the most common type of custom control. It is basically the standard method for making XAML based content in a WPF application. These can be reused like other controls, but are more suited for single use such as the content of a dialog or window or something else that is specific to a single application.
Some Other Control
You can also extend an existing control to add additional functionality to it. This way, you still get all the features the control offers and only have to implement the additional bit.
For example, I have a custom control called an AutoScrollRichTextBox that extends RichTextBox. So, it does everything a RichTextBox can do. It also has the ability to automatically scroll to the bottom when content is added to the text box (which it only does if the text box was already scrolled to the bottom before the addition content was added).
I could have implemented that feature as an attached property instead of an extension of the control (and maybe I should have), but it works, and I have used it in three different applications (as an output window and as a chat log). So, I am happy with it.
In the end, it really is just a matter of how self-contained, reusable, and easy to drop in you want a control to be. If there is already a control that does what you want, and you just want it to look different, then you should definitely use styles and templates to achieve that. However, if you want to make something that doesn't already exist, limiting yourself to using only styles and templates will make the implementation work harder and make the end result less reusable and more difficult to set up additional instances (unless all instances are identical).
The examples of making things like buttons that look different are not examples of what you should use a custom control for. They are just examples of how someone would go about making a custom control for the purpose of teaching the details of the process. If you actually want a customized button, just customize a button.

How do I adjust the size of the dropdown portion of the a combobox with PyQt

I'm creating a program where the width of column needs to be relatively narrow, but when I add a combo box I have to increase the width so that I can read the listings in the drop down. I know that in HTML the drop down adjust to the length of longest entry, in Iron Python you can adjust the drop down width manually, but I can't seem to find any reference to either of these options in PyQt. If I'm missing it in the documentation, a friendly pointer to the right spot would be of great help. Thanks.
The dropdown portion is a component that inherits QAbstractItemView (usually QListView).
It is accessible via the view() getter of the QComboBox. You can play with its sizePolicy to get what you want.
If it is not satisfying, you can even set your own QAbstraItemView to the QComboBox via `setView'.
In Qt a widgets size is usually controlled by its layout. The layout management docs should help. In particular, take a look at QSizePolicy. If you're using designer, you can set these directly as properties, otherwise you'll need to do it in code. The basic layouts example may help as well.

How to create a shape acting like a textbox?

Please refer this control
http://www.charlespetzold.com/blog/2009/10/Using-Text-Outlines-in-Silverlight.html
The formattedtext control is a shape which helps to generate the shape of the text with proper geometry. I would like to make this control act like a text box with cursors and features like typing in from keyboard.
Right now I use an invisible text box with a formattedtext control to act like that. But the cursor position always creates a problem when the size of the text is not equal to the size of the rendered text as shape.
Can anyone please show the way to achieve this.
Well, I built a syntax highlighting textbox using the method you describes.
Actually, at first I wanted to rebuilt everything too, but I thought : I have to build the caret fonctionnalities, the selection brush, manage a lot of different events, like selection with mouse or keyboard, deletion, Copy/Cut/Paste, etc etc...
That's a LOT of work, and windows users are used to select text in textboxes for instance, so this complex implementation cannot be left unimplemented. We must follow some Microsoft guidance on how a textbox must feel.
Actually, I think that building a new textbox from scratch is not the way to go. I suggest you to continue on your current method. If you have different fonts in the same textbox, use a RichTextBox, and handle the font changes in the textbox as well as in the formatted text.
Also, a good think to implement is to only draw the visible text with the formattedtext (but only if the user can write several hundreds of text lines).

Complex .Net 2.0 Windows Forms control: where to start?

In order to make a convenient UI for an .Net 2.0 Winforms application I am working on, I have need for a control that I'm pretty sure goes beyond the "out of the box" behavior of any standard control. A mock-up of what I'm trying to achieve follows:
Mock up http://www.claware.com/images/temp/mockup.png
Essentially, this part of the application attempts to parse words into syllables from tribal languages (no dictionary to refer to; any and all unicode characters are possible.) By the time the user gets this far, he has already defined the vowels / consonants in his language and some other configuration. There is then an iterative process of (1) the application guesses which syllables exist in the language based on some rules, (2) the user refines the guesses, selecting the correct parsings or manually parsing a word, (3) the application "learns" from the user's feedback and makes smarter guesses, (4) repeat until the data is "good enough" to move on.
The control needs to present each word (the grey headers), then all the syllable break guesses (the white areas with dots separating the parts of words.) There is also a way to manually enter a parsing, which will display a text area and save button (at the bottom of the mockup.) When the user hovers over a guess, the background changes and "accept / reject" buttons appear. Clicking on the accept, or entering a manual parsing, removes the entire word from the list. Clicking the reject button removes just that item.
I'm by no means 100% sold on the formatting I have above, but I think you can get a general idea of the types of formatting and functional control I need. The control will also scroll vertically--there may be thousands of words initially.
My question for you experienced WinForms developers is: where to start? I would really, really like to stay within the .Net core framework and extend an existing control as opposed to a third-party control. (At the risk of starting a religious war: yes, I suffer from NIH-syndrome, but it's a conscious decision based on a lot of quick-fix solutions but long-term problems with 3rd party controls.) Where can I get the most "bang for my bucK" and the least reinventing the wheel? ListView? ListBox? ScrollableControl? Do I need to go all the way back to Control and paint everything manually? I appreciate any help that could be provided!
[Edit] Thanks everyone for the ideas. It seems like the most elegant solution for my purposes is to create a custom control consisting of a FlowLayoutPanel and a VScrollBar. The FlowLayoutPanel can contain instances of the custom controls used for each word. But the FlowLayoutPanel is virtual, i.e. it only contains those instances which are visible (and some "just out of scroll"). The VScrollBar events determine what needs to be loaded. A bit of code to write, but isn't too bad and seems to work well.
I would look at the TableLayoutPanel and FlowLayoutPanel controls. These will let you organize a series of controls with moderate ease in a vertical fashion. I would then create a UserControl that consists of a label and 2 buttons. The UserControl will expose properties like Text and events that are exposed for the button clicks.. For each entry in the list, you will create an instance of the UserControl, assign the text value, and handle the click events. The instance will be placed in the Table/Flow panel in the correct order. Both of those layout panels do allow for inserting items between other items so you can add/remove items from the list dynamically.
Edit:
Given the length of what you are trying to render, I would consider using the DataGridView and do some custom rendering to make it perform how you want it to work. Using the rendering events of the DGV you can merge columns, change background colors (like highlighting the dark gray lines), turn on/off the buttons, and handle changing the grid into edit mode for your rows to allow modification or inserting of new values. This method would easily handle large datasets and you could bind directly to them very easily.
Well, this certainly looks like a candidate for a custom component that you should be creating yourself. You can create this using standard .Net drawing commands along with a text-box, and a regular button control.
Now you want to find out where to start.
Create a Windows Forms Control Library project.
Drop in the textbox and the button control.
The panel drawing code should preferably be done by code. This can be done using the regular GDI+ commands.
Edit:
Here's another idea, and one that I've practically used in my own project with great success.
You could use a web-browser control in the app, and show your data as html. You could update the source of the web-browser control based on the input in the textbox, and clicking on the links in the web browser control will give you the event that you can trap to do some action. Your CSS will work.
I used this technique to build the 'desktop' in an app I made called 'Correct Accounting Software'. People loved the desktop so much that it is one of the best loved features of the app.
Here's how I would do it:
Create a custom control. In this custom control, have a ListBox atop a LinkButton, and when the LinkButton is clicked you can make it give way to a TextBox. The ListBoxes will have the top row unselectable... you can probably get the rest from there. When you get your list of words, fill a Scrollable of some kind with one control for each word:
(foreach String word in words){
myScrollable.add(new MyComponent(word));
}
From there, I'm not sure what you want to do with the boxes or the data, but that's my initial idea on the UI setup.
Use the WebBrowser control and generate the HTML markup into it using DocumentStream or DocumentText.

wpf / silverlight textbox filter design

I have a list that the user can filter in several ways. two of which lend themselves to combo boxes and two that need to accept user input. For example, one textbox allows the user to type in any part of a list item's description, and the dialog will only present items whose description contains the text entered.
It is a dialog 'picker' type of window, so space is at a premium. I'd like for the text boxes not to require a traditional label. Instead, when the dialog is first invoked, the label (ie, "Description") is grayed out, centered, and in italics. Maybe a tool tip to further make it obvious to the user what it's for. When the user starts to type, the faux label disappears and the entered text is normal left aligned text.
Does wpf / silverlight have any native support for doing something like this? I guess it could be a combination of styles and eventing. I'd rather not invent any wheels that might be out there (I got the idea specifically from looking at Tortoise' "Show Log" window, but I've seen it before).
Does anyone have any sample code they can share to do this? Or a an alternative idea that also saves space and simplifies the layout?
Cheers,
Berryl
Kevin Moore's InfoTextBox, which is part of his Bag-O-Tricks is the kind of thing I was looking for, almost exactly. This is also the 'watermark' (great name - I would have found this sooner if I had known that) text box from another post.

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