Develop Reference

Using Binding.IndexerName and Binding.ProvideValue in Xamarin Forms

I am trying to implement the answer in this so question
The problem is, that in xamarin forms 2 ingredients do not exist (or I have not found them yet):
Binding.IndexerName
Binding.ProvideValue()
I do not know why they do not exist. Maybe nobody has implemented them, maybe there is a technical reason why they cannot be implemented.
Can I still get the in xamarin forms?
Maybe in another way?

First, note that this answer probably doesn't work with Xamarin.Forms, or at least not with XamlC on.
If you want to get that working, your MarkupExtensions have to implement IMarkupExtension<BindingBase> instead of IMarkupExtension.
ProvideValue() is not defined in the Binding class, but in BindingExtension, but you probably won't win anything by instantiating a BindingExtension and calling ProvideValue on it versus returning the Binding directly.
The IndexerName refers to the IndexerName attribute of the Translator class. As you're not using it, the default is "Item", and you can use that hardcoded value.

WP7 - Data bound value in custom control, how to set default string so it's visible in designer

I'm fairly new to WP7 and totally new to Expression Blend.
I have a ListBox bound to a List of custom objects,
List<Person>
Each item in the list contains a custom control, MyControl which is bound to Person.
MyControl contains a TextBox which is bound to the Username property of Person.
All of this works fine. My question is: how do I set a default value for the TextBlock so that it becomes visible in the Designer or ExpressionBlend? With it being data bound, it has no text till it runs ... so I can't actually do any fancy styling using these wonderful tools unless I repeatedly delete the binding code to replace it with a string, make the changes, replace the binding code, repeat. Seems long winded!
Thanks,
Steven

What you want is "Design time data".
There are a number of ways of doing this. Fortunately there are also lots of resources online which explain it.

#Steven Have you looked at creating sample data in Blend to do what you require and then some binding to actually attached the data to the control bound to your list? You might like to check out Blend Sample Data as it guides you through a simple example of doing just that. You might then be able to adapt to to your own ends.

It depends if you are using any MVVM model or not.
My suggestion, if you are not using a MVVM, is to use Blend Sample data, is fast and quick.
If you are MVVM Light I've found very usefull to create two files:
DataService.cs - contains the real connection and data
DesignDataService.cs - contains the sample data
The two libraries are identical, from an call perspective so that in the ViewModelLocator you can swap them:
if (ViewModelBase.IsInDesignModeStatic)
{
SimpleIoc.Default.Register<IDataService, Design.DesignDataService>();
}
else
{
//SimpleIoc.Default.Register<IDataService, Design.DesignDataService>();
SimpleIoc.Default.Register<IDataService, DataService>();
}
In the Design class I've decided to create an XML file for each Model so that it's easy to change the sample data and test all possible scenarios.
I then use the Deserialize function to read it:
csNodeList _Copyrights = new csNodeList();
resource = System.Windows.Application.GetResourceStream(new Uri(#"Design/sampledata.xml", UriKind.Relative));
streamReader = new StreamReader(resource.Stream);
serializer = new XmlSerializer(typeof(csNodeList));
_Copyrights = (csNodeList)serializer.Deserialize(streamReader);
Please note that the file sampledata.xml has to be stored in folder Design and must be defined as Content not as Resource.
It is suggested to improve performance and load time.
M

Parsing a Auto-Generated .NET Date Object with Javascript/JQuery

There are some posts on this, but not an answer to this specific question.
The server is returning this: "/Date(1304146800000)/"
I would like to not change the server-side code at all and instead parse the date that is included in the .Net generated JSON object. This doesn't seem that hard because it looks like it is almost there. Yet there doesn't seem to be a quick fix, at least in these forums.
From previous posts it sounds like this can be done using REGEX but REGEX and I are old enemies that coldly stare at each other across the bar.
Is this the only way? If so, can someone point me to a REGEX reference that is appropriate to this task?
Regards,
Guido

The link from Robert is good, but we should strive to answer the question here, not to just post links.
Here's a quick function that does what you need. http://jsfiddle.net/Aaa6r/
function deserializeDotNetDate(dateStr) {
var matches = /\/Date\((\d*)\)\//.exec(dateStr);
if(!matches) {
return null;
}
return new Date( parseInt( matches[1] ) );
}
deserializeDotNetDate("/Date(1304146800000)/");

Since you're using jQuery I've extended its $.parseJSON() functionality so it's able to do this conversion for you automatically and transparently.
It doesn't convert only .net dates but ISO dates as well. ISO dates are supported by native JSON converters in all major browsers but they work only one way because JSON spec doesn't support date data type.
Read all the details (don't want to copy blog post content here because it would be too much) in my blog post and get the code as well. The idea is still the same: change jQuery's default $.parseJSON() behaviour so it can detect .Net and ISO dates and converts them automatically when parsing JSON data. This way you don't have to traverse your parsed objects and convert dates manually.
How it's used?
$.parseJSON(yourJSONstring, true);
See the additional variable? This makes sure that all your existing code works as expected without any change. But if you do provide the additional parameter and set it to true it will detect dates and convert them accordingly.
Why is this solution better than manual conversion? (suggested by Juan)
Because you lower the risk of human factor of forgetting to convert some variable in your object tree (objects can be deep and wide)
Because your code is in development and if you change some server-side part that returns JSON to the client (rename variables, add new ones, remove existing etc.), you have to think of these manual conversions on the client side as well. If you do it automatically you don't have to think (or do anything) about it.
Two top reasons from the top of my head.
When overriding jQuery functionality feels wrong
When you don't want to actually override existing $.parseJSON() functionality you can minimally change the code and rename the extension to $.parseJSONwithdates() and then always use your own function when parsing JSON. But you may have a problem when you set your Ajax calls to dataType: "json" which automatically calls the original parser. If you use this setting you will have to override jQuery's existing functionality.
The good thing is also that you don't change the original jQuery library code file. You put this extension in a separate file and use it at your own will. Some pages may use it, others may not. But it's wise to use it everywhere otherwise you have the same problem of human factor with forgetting to include the extension. Just include your extension in some global Javascript file (or master page/template) you may be using.

(.net) Kind of design question

My typical application has a couple of textboxes, checkbuttons, radiobuttons, and so. I always want to load the settings the user used the last time when the program starts, and also want to save the settings as the users clicks "Save settings" or closes the application. When the user attempts to save the settings, I'll have to check each of the controls for input errors (sometimes they have to have a max length, other times only caps, other times other things, there isn't a rule for them all, everytime it'll be different), and only if everything's OK i'll let him save the options. If there is something wrong, no option is saved and my errorcontrol provider will pop up a description of the input type info that should be put in that control.
I've been designing this from scratch for all my projects, but it's being a pain to do it. So I'd thought maybe now was the time to do some library to help me. I thought initially that maybe it'd be a good idea to have all the controls on my form that are going to be part of this save/load process to have an attribute associated with them, something like this
public delegate bool InputIsOkHandler();
public class OptionsAttribute : Attribute {
public Control controlRef;
public InputIsOkHandler IsInputOk;
public string errorMessageToShowOnErrorProvider;
public OptionsAttribute(Control controlRef, InputIsOkHandler inputHandler, string errMessage) {
...
}
}
The main problem here is that when I declare the attribute on a given var:
[Options(...)]
TextBox textBox1 = new TextBox();
I'll get
Error 1 An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type.
So I guess this approach isn't the best one. What would you guys do in this situation? Would you use attributes? Would you use other mechanisms?
Thanks

Do you know that .NET already includes such a system since 2.0? See MSDN, CodeProject and this white paper from WestWind.

The Personalization and User Profiles supported in ASP.NET 2.0 can be a nice way to achieve your goal.
You can check this MSDN article for a overview Personalization in ASP.NET 2.0

Localization for Winforms from designmode?

I need to bind labels or items in a toolstrip to variables in Design Mode.
I don't use the buit-in resources not the settings, so the section Data is not useful. I am taking the values out from an XML that I map to a class.
I know there are many programs like:
http://www.jollans.com/tiki/tiki-index.php?page=MultilangVsNetQuickTourForms
but they work with compiled resx. I want to use not compiled XML.
I know that programatically i can do it, i create a method (for example, UpdateUI()), and there I assign the new values like this:
this.tsBtn.Text=Class.Texts.tsBtnText;
I would like something i could do from Design Mode or a more optimized way than the current one. Is there any Custom Control out there or Extension?

Aleksandar's response is one way to accomplish this, but in the long run it's going to be very time consuming and won't really provide much benefit. The bigger question that should be asked is why do you not want to use the tools and features built-in to .NET and Visual Studio or at least use a commercial third-party tool? It sounds like you are spending (have spent?) a lot of time to solve a problem that has already been solved.

Try with inheriting basic win controls and override OnPaint method. Example bellow is a button that has his text set on paint depending on value contained in his Tag property (let suppose that you will use Tag property to set the key that will be used to read matching resource). Then you can find some way to read all cache resource strings from xml files (e.g. fictional MyGlobalResources class.
public class LocalizedButton : Button
{
protected override void OnPaint(PaintEventArgs pevent)
{
base.OnPaint(pevent);
this.Text = MyGlobalResources.GetItem(this.Tag.ToString());
}
}

You can use satellite assemblies for localization and generate them using your XML file as a source for the translated entities.
more about satellites http://msdn.microsoft.com/en-us/library/21a15yht(VS.71).aspx
sure it's not from design mode, but there's no way to do it this way with your restrictions.