CODEWITHSUNDEEP
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Erez
Erez

Reputation: 6446

How to Databind TextBox to Property in CodeBehind

I am using Expression Blend.

Let's say I got:

Public string FirstName{get;set;}

Edit: thanks for the answers, but I'm afraid people didn't understand my question. I do know how to Bind Data in Code or in XAML.

My question is if there is a way to do all that with the Expression Blend Interface without writing it directly. Only with mouse movements.

Upvotes: 2

Views: 11217

Answers (2)

iCollect.it Ltd
iCollect.it Ltd

Reputation: 93601

You would actually want to put the property on a View Model, and use XAML binding, but that is another story.

As you describe your example, you would first need to implement the "FirstName" property as a Dependency Property and not a simple get/set. Here is a great code-snippet from Shawn Wildermuth to save lots of typing (there is a single typo in the snippet you need to fix - "($type$)args.NewValue;"... NewValue has the wrong case in the snippet).

You can bind in XAML to a simple get/set property, but it is a one-way/one-time binding and will not update with changes.

In code, the binding requires two things to be set.

  • Set the DataContext of the control (or the page) and
  • Set a data binding on the control.

For the example you mention you could use code like the following (assumes a TextBox control called myTextBox in the Xaml):

using System.Windows;
using System.Windows.Controls;

namespace BindingCodeTest
{
    public partial class BindingCode : UserControl
    {
        public string FirstName
        {
            get { return (string)GetValue(FirstNameProperty); }
            set { SetValue(FirstNameProperty, value); }
        }

        // Using a DependencyProperty as the backing store for FirstName.  
        // This enables animation, styling, binding, etc...
        public static readonly DependencyProperty FirstNameProperty =
        DependencyProperty.Register("FirstName",
                                     typeof(string),
                                     typeof(BindingCode),
                                     new PropertyMetadata(string.Empty,
                                     new PropertyChangedCallback(OnFirstNameChanged)));

        static void OnFirstNameChanged(object sender, DependencyPropertyChangedEventArgs args)
        {
            // Get reference to self
            BindingCode source = (BindingCode)sender;

            // Add Handling Code
            string newValue = (string)args.NewValue;
        }

        public BindingCode()
        {
            InitializeComponent();
            myTextBox.DataContext = this;
            myTextBox.SetBinding(TextBox.TextProperty, new System.Windows.Data.Binding("FirstName"));
            FirstName = "First name";    // Sample change
        }
    }
}

Upvotes: 6

VyvIT
VyvIT

Reputation: 1098

In Blend 4, on the 'Data' tab > New sample Data.. > name data source as you like, f.e. 'MySampleDataSource'. Then your 'MySampleDataSource' will have a '+' button (the same Data tab on the right) with 3 options. Choose 'Add simple property' and name it 'FirstName'. Then drag that property on your TextBox or TextBlock.

The result is like this:

<TextBlock x:Name="firstName" Text="{Binding FirstName}"/>

Upvotes: 5

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