Skip to main content

Posts

Showing posts with the label Binding

Propagating Property Change for Static Properties

While working on any XAML based app, first thing which comes into mind is Binding . There are lot many articles on what is Binding and how it works. Don’t worry, I am not going to repeat all that stuff again. But definitely, I would like to touch upon few things which are base of my today’s write-up. To make any property bindable or let’s say to propagate property change, we usually follow one of the below two options: Implement INotifyPropertyChanged interface or Create an event with name PropertyNameChanged Point to notice here is, both the above options will work only on instance properties. Now what if my property is Static??? INotifyPropertyChanged is not going to work for static properties. None of the above options will make x:Static extension work. What to do now ? No worries, all these hazards can easily be overcome when you will jump to .Net 4.5. Approach 1: Property specific static event for each and every static property Let’s have a look a...

Gotcha with StringFormat

Hope most of you have used StringFormat property on your binding to render the formatted value on the user interface. But are you aware about one of its secret. Well before revealing that secret, let’s have a look at how StringFormat works with binding. Scenario problem: I am taking an example scenario, in which my text box will display amount till three decimals.  Now there are multiple ways to achieve this. One way can be by using Converters, another way can be by using StringFormat along with TextBox binding. Perhaps there can be more ways apart from these two ;) In below sample I am going to take StringFormat trick to achieve this and code to perform this operation is very straight forward as: <TextBox Text="{Binding Amount,StringFormat=f3}" /> With above code, whenever you will lost focus from your TextBox, given amount will be displayed as three decimal points. Till here everything is perfect as expected BUT with one downsize. Important...

Binding Source Objects in WPF

Recently I received a request from one of the followers on ways to bind source objects. So, I thought it would be a nice topic for a post. Hence, it's here. For a binding to work, there should be a source object. The selection of source object is totally dependent on the way binding is used. If no binding source is provided, then bydefault DataContext of an element is used. The most common way is to set DataContext on parent element and let it flow to all its children. But apart from this, there are 3 other ways by which one can point to source object:  1) RelativeSource - Relative source is one of the property on a binding that can point to relative source markup extension which tells where the source can be found in hierarchy. In simple words, it is the relative path in the element hierarchy. 2) ElementName - Another way of specifying source is by using ElementName in which other element present in the current UI can be used as a source object. Here the source object...

DataTemplating Overview

DataTemplate is a very powerful concept which allows you to provide a visualization for your objects in your application. DataTemplate objects are very useful specially dealing with collections. If you bind your collection with any of the ItemsControl, say ListBox then by using a DateTemplate one can change the appearance of data objects very easily. Well, now let's create a DataTemplate quickly. Let's start by creating a class called Employee: FirstName and Age will be our business objects that will reside in our application. Now we will go ahead and show the value of these objects on screen in a WPF application. For that our XAML will look like: Now looking at the code-behind: In code-behind, we have set the values for FirstName and Age with DataContext of main window. So, that XAML can bind to these values via EmployeeDetail property. At this point of time, if you will run the application, you will see: By above image yo...

Simplest MVVM Ever - MVVM series 2 of n

Continuation to my previous article on  WHY and WHEN of MVVM , this time, I am going to tell something on how we can create a simple MVVM application with minimal complexities. I am writing this article for those, who just want to see quickly how MVVM works. It doesn't do anything fancy and uses some basic databindings and commanding stuff. This article will be helpful for all those who are looking for a quick example of how to hook the View to the ViewModel and how commands plays a role.  Today if you will surf internet, you will came across 1000s of articles discussing on what is MVVM and what are the major building blocks of it. So, I am going to repeat the same crazy thing again. But definitely, I'll brief you about major building blocks in layman, in order to make it easier to understand for beginners. Excited, eh ???  Layman introduction of building blocks    So, let's quickly start with three main layers of MVVM. Model  - Model contain...