I am a newbie to xaml and windows app dev so sorry if this question might seem silly.
I created a textbox and in the designer I right clicked it and selected edit template=>edit a copy and put it into my custom dictionary.
In the control template for this textbox I saw visual states like disabled,focused and so on. And I modified them and run the mobile app and observed that my changes work like changing border color when textbox is focused.
But in order for this to work somebody has to call
VisualStateManager.GoToState("Focused")
when the textbox is focused so who is calling this because I don't see any visual transitions in the control template so how is this happening?
The code in the control itself is calling VisualStateManager.GoToState(...) .
When you start implementing your own custom controls, you might subscribe to events you have available and transition states based on your own logic. Here is an example of a custom control with its own two custom states.
https://github.com/xyzzer/WinRTXamlToolkit/blob/master/WinRTXamlToolkit/Controls/WatermarkTextBox/WatermarkTextBox.cs
XAML is a compiled language, and if you've looked extra close, what happens under the hood, is that the class behind your xaml has the same namespace as your xaml code.
This means (for no practical purpose) that compiling your program turns all of that XAML into C# code before then going over to MSIL and eventually execute as a binary program.
Much of the state changes that happen are event based, and TextBox, like all other user controls, will transmit a message and listen to messages. The Page that contains the TextBox will probably be the one that transmits a state change whenever one of it's children gets focus, and as a good control, the TextBox listens for this event and reacts to it.
Related
I'm working in a legacy application using MFC.
We have a mechanism to enable/disable controls depending on some business logic.
This mechanism is implemented in the CView-derived class. The way it works is all the views in the application derived from a common CView-derived class (CBaseView) and on the PreTranslateMessage all controls of the view are enabled/disabled.
This worked fine so far because all controls send at least WM_PAINT message when they need to be painted. So the system worked without the user having to move the mouse or anything. I recently added some drawing features and I had to use WS_EX_COMPOSITE to get ride of some flickering. With this flag activated my CView-derived class is not getting any called to PreTranslateMessage when creating the view....so the controls are not disabled until the user moves the mouse over the control.
I understand there is no way to send WM_PAINT using WS_EX_COMPOSITE but is there other message I can use to get the same behaviour???
Edited:
I am currently using the OnIdle approach but it has a big drawback, the windows doesn't become idle until after drawing all the controls...so when you enter the screen al controls are enabled and inmediately they are disabled...this makes a quite ugly effect!
More solutions???
Thanks in advance...
The logical place to enable/disable controls would be CView::OnUpdate, it is called by the framework after the view's document has been modified and from OnInitialUpdate(); you can also call this function if there is some change that would trigger re-evaluation of your business logic.
EDIT
After reading the question a bit more closely, what you could also do is to post a private message at the end of OnInitialUpdate and "catch" it in your PreTranslateMessage:
PostMessage(WM_APP, 0, 0);
Calling InvalidateRect followed by UpdateWindow against the window in question will mark the entire client area as dirty and force an immediate repaint. Remember that WM_PAINT is not really a message, in the queue in the usual sense, it is pushed out after all other messages have been processed for that window, which would include any invalidations of the area being drawn. No message is generated at all if there are no invalid segments of the active window display.
I am new to MFC. In the project I am working on the dialogs are created in resource file(.rc).
In that there are OK button(id ID_OK) and Help button (id ID_Help). I am not able to find the event handlers for these two buttons. There are other buttons where the event handlers mapped are easily found. If someone teach me how to find those event handlers it would be very helpful.
And how can I find the functions which get called on clicking of the particular button by debugging in visual studio?
Thank you.
Double click the button (shown in rc) opened in Resource View in Visual Studio and you will be automatically placed by Studio where the Event handler is located in your code.
If this does not work, then probably delete the Button with ID's ID_OK and ID_Help in your resource view and again add it to the resource using different ID and then try to generate the event handler by double-clicking those buttons in resource view. This is because sometimes the value of ID's conflict with other ID values and hence Studio is not able to generate the Event-handler for you in that case.
Buttons don't have direct event handlers as in other frameworks (like in C#, WinForms etc). You must use message-maps in MFC.
ID_OK maps to virtual function CDialog::OnOK, you can just write your virtual function implementation. Framework will call it for you. You can also handle this message with WM_COMMAND message entry.
There is no standard resource ID as ID_Help - it is always capital, and has to be always in caps! No one is stopping you from using small letters, though - it for consistency and better readability.
Instead of fiddling with resource files (.RC and resource.h), mapping the same with your dialog class and things like that. I suggest you to go, and learn, without resource file. Start with drawing in frame (circles, filled-triangles whatever). Learn and know why virtual function are there for some messages, and message-maps for other (most) messages.
My two cents.
Does MvvmCross support a cross platform solution for displaying alerts or popups?
Searching the code I found MvxDialogActivityView but it has been commented out. Will this remain the case for now?
If there is no direct support how would you suggest this is best done? (Perhaps the ViewModel would change a property and call FirePropertyChanged so that the View would be aware of it and show an alert.)
Edit 16:04 16th June 2012
What I am trying to do for this specific case is as follows:
On the page a button is clicked, which causes a method to run in the ViewModel which does an evaluation to determine which of two messages should be shown to the customer. The message would be shown as an alert or popup (either native, or preferably totally styled by me). The message would fade after (the click of the OK button, or preferably 3 seconds).
After the message has been dismissed a new page will be navigated too (depending on which of the two messages was shown).
How to handle this definitely depends on what the situation is - there's no single best rule (IMHO)
For a general error display pattern, there's one proposal at http://slodge.blogspot.co.uk/2012/05/one-pattern-for-error-handling-in.html
I've used similar patterns for showing application level notifications - e.g. for when a long running operation completes or when a chat message arrives or...
One interesting post about how to display message boxes was: http://awkwardcoder.blogspot.co.uk/2012/03/showing-message-box-from-viewmodel-in.html - I'm not sure I'd completely follow the end solution, but there are definitely some good points there about what not to do.
For your updated scenario, I would consider using a messenger (like TinyMessenger) or using normal C# events exposed by the ViewModel and consumed by its View
On the page a button is clicked, which causes a method to run in the ViewModel
I would implement this using an ICommand bound to the button Click/Tap/TouchDown
which does an evaluation to determine which of two messages should be shown to the customer.
I would definitely implement the logic within a Service
This would be called from the ViewModel - and the result/decision would probably cause some property or private field state change.
How does the View then decide to show a message? I can think of 3 options:
The View could just respond to a Property change (normal Mvvm INPC) - this would be my preference
The ViewModel could expose a normal C# event which it triggers...
The ViewModel could send a Message
This last option (Messenging) is probably the most flexible solution here - it decouples the View and ViewModel in case you later decide to change responsibilities. To implement messenging, either:
implement your own hub (like I do for errors in http://slodge.blogspot.co.uk/2012/05/one-pattern-for-error-handling-in.html)
or use a generic solution like TinyMessenger
The message would be shown as an alert or popup (either native, or preferably totally styled by me).
This is a View concern - so would be entirely controlled by the View project. I'd use controls like: UIAlert, Toast, ToastPrompt, etc - all of which can be styled
The message would fade after (the click of the OK button, or preferably 3 seconds). After the message has been dismissed...
I'd use some form of Code Behind (or maybe a Behaviour in WP7) in the View. This would detect the click/fade/disappear and would then invoke either an ICommand (my preference) or public method on the ViewModel
a new page will be navigated too
This navigation would be requested from the ViewModel
(depending on which of the two messages was shown).
This would be easy to track through the above flow... presumably the ViewModel already knows what to show.
So that's what I'd do...
it keeps the application flow logic inside the ViewModels (and lower)
it keeps the presentation inside the Views
...but I'm sure there are other options :)
One final note... the fade out and then navigate logic can really get "messed up" by Switching/Tombstoning on WP7 and Android - this may or may not matter for your particular scenario.
I have already asked the same question but in regards with MDI Application design. Now just for R&D purpose so that we can go with 2 solutions to our user. Can somebody plz help me out...
We are developing an OutLook Style Application using C# Winforms. In that application we are using Microsoft Table Control. Which is what we need to show our UI. In the left hand pane we have menu and in the right hand we are displaying our UserControl. Like CustomerManager. This UserControl is doing Adding, Updating, Deleting ect etc but we want to put the common action buttons, Like Add,Delete,Save on the top toolbar.
So far so good, Now what we need to acheve is regardless of UserControl. What ever UserControl is loaded in the MainForm's TableControl. When the save button is clicked it should process the data on that UserControl. Obviously we will write the logic of the Save Action on each UserControl.
Please help...
Regards
Shanx
I may advice you the Krypton Toolkit. You will write an Outlook style app in seconds.
For all who ended up here like me in search of a free toolkit: As Vulkanino suggested to use Krypton, I loooked it up.
This is now open source Freeware and can be found unter: Krypton Toolkit
Create a Base user control that contains your Add, Delete, Save methods and events. Then create every other functional control that inherits from the Base control.
When you action the main toolbar buttons, you can safely cast each user control in your given container, to the Base user control.
Some MSDN links you might want to read up on:
http://msdn.microsoft.com/en-us/library/44a9ty12(VS.80).aspx
http://msdn.microsoft.com/en-us/library/ms173149(VS.80).aspx
I have 2 webparts which are connected, where the provider sends a string to the consumer.
However it fails to work if I put any TextBox controls in the consumer webpart. (works fine if I use a Label or Literal control.
The idea is that the consumer is to be composed of form controls like TextBoxes.
e.g. the codeproject sample at http://www.codeproject.com/KB/sharepoint/ConnectingCustomWebParts.aspx
Works fine... until you replace the consumer Label control with a TextBox.
Any help gratefully received.
Well, if this still needs an answer....
Why it would work with one control and not another, I'm not sure. The reason I couldn't get it to work consistently as is coded in that sample is due to the issues brought to fore in this article. The data just isn't always there in the create controls part of the web part life cycle. I had much better luck getting my data and putting it somewhere, either the session or the viewstate during the ConnectionConsumer event, then setting the value to the control that needed to display it in the OnPreRender event, or just somehow binding to the control, say in a grid, and just calling refresh on the List I was using as a datasource in the OnPreRender, calling Refresh in the create controls didn't work reliably, only in OnPreRender.
Once I truly grokked the web part lifecycle, things became much simpler for me, and finally taught me why in Java portlets they went with the post/redirect/get cycle to try and avoid this very granular coordination between various portlets on a page.