New FrameworkPropertyMetadata(string.Empty, OnPasswordPropert圜hanged)) Public static readonly DependencyProperty PasswordProperty =ĭependencyProperty.RegisterAttached("Password", To get up and running, let’s add a new PasswordBoxHelper class to our project, and add the implementation from the second link: Well, no problem! It turns out that there actually is an MVVM-friendly way to bind the password – see the PasswordBoxAssistant and PasswordHelper implementations. You see, the Password property can’t be bound specifically because it shouldn’t, but let’s say that we’re like most other developers and we’re so blinded by this MVVM dogma that we don’t care about the security concerns and we want an MVVM-friendly solution. Oh no! What are we going to do now? If we can’t bind the password, and have to somehow retrieve it from the control, then we’ll break the MVVM pattern, right? And we MVVM knights-in-shining-armour can’t afford to deviate from the path of light that is MVVM. Now, you’ll notice right away that something’s wrong when you see the blue squiggly line at the password binding: Let’s go with this (just make sure the namespace matches what you have): Now we can build our form by editing the XAML in MainWindow.xaml. Right, now let’s add a couple of properties to our MainWindowViewModel that we’ll want to bind to: This.DataContext = new MainWindowViewModel() ), set up your window’s DataContext by adding the following line at the end of your constructor: Create a new WPF application, and then add a new class called MainWindowViewModel. Right, so let’s set up something we can work with. This article is a little advanced in nature, and assumes you’re familiar with WPF and MVVM. And I’m also going to show you why it’s a very bad idea to do this. In this article, I’m going to show how the password can be bound in the ViewModel despite this limitation. The thing is that you can access the password entered by the user using the Password property, but it’s not a dependency property, and MVVM purists don’t like the fact that they can’t bind it to their ViewModel. In WPF circles, the PasswordBox control has generated quite a bit of discussion. The original premise of this article was that binding the password would expose it, but it turns out that it is already exposed regardless of whether you use data binding or not. Update 1st October 2018: As ZXeno posted in the comments, there seems to be a security flaw in the PasswordBox control by which it is possible to snoop passwords directly. You need to login with Twitter to share a Thought on this post.This article was originally posted here at Programmer’s Ranch with the title “C# WPF/MVVM: Why You Shouldn’t Bind PasswordBox Password”, on 4th October 2014. See the pretty little dot button? Me neither! In fact, the only keyboard I've seen that has this button is my iPhone (which doesn't run Visual Studio, so it won't help me here).Īnyways, to type a dot (or bullet), position the cursor, hold down the RIGHT ALT key, type "0149" using the keypad (without the quotes) and release the RIGHT ALT key. Now that we all have iPhones and run Vista and log into millions of forms on the web each day, we are used to seeing pretty little dots show up when we type in a password. For example, if you try to copy text to the clipboard from it, the text "Password" is pasted. (I've noticed some other cool functionality that pushes this beyond a glorified TextBox. If left blank, the user's characters are displayed. The ASP.NET TextBox control has a TextMode enum that you can set to "Password." After you set this property, your TextBox will display dots or starts (inherited from OS settings) instead of the characters typed.īut in WPF, password field functionality has been broken out into a separate control, the PasswordBox.There is a PasswordChar property that takes in a char that will be displayed. I'm writing my first WPF form and one of the fields is a password.
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