Question

I defined an object which contains properties in code-behind and, want to set the object to datacontext in xaml.

namespace WpfApplication4
{

    public partial class MainWindow : Window
    {
        public EquipInfo equip1;

        public MainWindow()
        {
            InitializeComponent();

            equip1 = new EquipInfo();
            //  setting here works fine but i want to do in xaml
            //textBox1.DataContext = equip1; 
        }
    }
}

here’s xaml code..

<Window x:Class="WpfApplication4.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TextBox Text="{Binding Path=PIN}" Height="23" 
                 HorizontalAlignment="Left" Margin="172,208,0,0" 
                 Name="textBox1" VerticalAlignment="Top" Width="120" />
    </Grid>
</Window>

Answer 1

You can set the DataContext via XAML to a public property. blindmeis has given a good example on how to do this.

What you did in your Post was not setting the DataContext, but binding the Text Property of your Control to a Property of the window. This only works if a DataContext is set. Another way to do that, if you don’t want to do MVVM (which I’d recommend, though), is referencing specific Elements in your Binding:

1.) Alter member to AutoProperty or similar

public EquipInfo equip1 {get;set;}

2.) Give your window a name

<Window x:Class="WpfApplication4.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Name="myWin"
    Title="MainWindow" Height="350" Width="525">

2.) Access Window Properties by instance name

<TextBox Text="{Binding ElementName=myWin, Path=equip1.PIN}"/>

On a side note, it would really be better to use a MVVM instead.