How to bind a simple string value to a text box?

Question

I am using wpf. I want to bind a textbox with a simple string type value initialized in xaml.cs class. The TextBox isn't showing anything. Here is my XAML code:

<TextBox Grid.Column="1" Width="387" HorizontalAlignment="Left" Grid.ColumnSpan="2" Text="{Binding Path=Name2}"/>

And the C# code is this:

public partial class EntitiesView : UserControl
{
    private string _name2;
    public string Name2
    {
        get { return _name2; }
        set { _name2 = "abcdef"; }
    }
    public EntitiesView()
    {
        InitializeComponent();
    }
}

I want to show value in textbox via binding . @RowlandShaw . to do it i wrote Text="{Binding Path=Name2}".... Am i doing wrong? — Dua Ali, Jul 20 '13 at 16:46
How to do this? can you explain me as i am beginner . Thank u @newStackExchangeInstance — Dua Ali, Jul 20 '13 at 16:51
I had this problem too, when I was a beginner. Here is the solution: http://stackoverflow.com/questions/14965796/wpf-databinding-not-updating — It'sNotALie., Jul 20 '13 at 16:53
@newStackExchangeInstance i am using usercontrol so how is it possible to use both INotifyPropertyChanged and usercontrol at a time ? — Dua Ali, Jul 20 '13 at 16:55

score 8 · Accepted Answer · answered Jul 20 '13 at 17:02

You never set the value of your property. Simply defining set { _name2 = "abcdef"; } does not actually set the value of your property until you actually perform the set operation.

You can change your code to look like this for it to work:

public partial class EntitiesView : UserControl
{
    private string _name2;
    public string Name2
    {
        get { return _name2; }
        set { _name2 = value; }
    }

    public EntitiesView()
    {
        Name2 = "abcdef";
        DataContext = this;
        InitializeComponent();
    }
}

Also, as people have mentioned, if you intend to modify your property's value later on and want the UI to reflect it, you'll need to implement the INotifyPropertyChanged interface:

public partial class EntitiesView : UserControl, INotifyPropertyChanged
{
    private string _name2;
    public string Name2
    {
        get { return _name2; }
        set
        {
            _name2 = value;
            RaisePropertyChanged("Name2");
        }
    }

    public EntitiesView()
    {
        Name2 = "abcdef";
        DataContext = this;
        InitializeComponent();
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void RaisePropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

Sorry about replying to this so late, but how does a form control subscribe to the PropertyChangedEventHandler? — William, May 27 '14 at 22:14

score 2 · Answer 2 · answered Jul 20 '13 at 21:30

2

Just add this line in your EntitiesView constructor

DataContext = this;

answered Jul 20 '13 at 21:30

UsmanAzam

539
4
15

Kurubaran · Answer 3 · 2013-07-21T08:01:36.220

Why dont you add a view model and keep your property there ?

View Model class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;

namespace WpfApplication1
{
    public class TestViewModel : INotifyPropertyChanged
    {
        public string _name2;
        public string Name2
        {
            get { return "_name2"; }
            set
            { 
                _name2 = value;
                OnPropertyChanged(new PropertyChangedEventArgs("Name2"));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        public void OnPropertyChanged(PropertyChangedEventArgs e)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, e);
            }
        }
    }
}

EntitiesView User Control

public partial class EntitiesView : UserControl
{

    public EntitiesView()
    {
        InitializeComponent();
        this.DataContext = new TestViewModel();
    }
}

How to bind a simple string value to a text box?

3 Answers3

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