Binding property to control in Winforms

Question

What is the best way to bind a property to a control so that when the property value is changed, the control's bound property changes with it.

So if I have a property FirstName which I want to bind to a textbox's txtFirstName text value. So if I change FirstName to value "Stack" then the property txtFirstName.Text also changes to value "Stack".

I know this may sound a stupid question but I'll appreciate the help.

Answer 1

You must implement INotifyPropertyChanged And add binding to textbox.

I will provide C# code snippet. Hope it helps

class Sample : INotifyPropertyChanged
{
    private string firstName;
    public string FirstName
    {
        get { return firstName; }
        set
        {
            firstName = value;
            InvokePropertyChanged(new PropertyChangedEventArgs("FirstName"));
        }
    }

    #region Implementation of INotifyPropertyChanged

    public event PropertyChangedEventHandler PropertyChanged;

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

    #endregion
}

Usage:

 Sample sourceObject = new Sample();
 textbox.DataBindings.Add("Text",sourceObject,"FirstName");
 sourceObject.FirstName = "Stack"; 

Answer 2

A simplified version of the accepted answer that does NOT require you to type names of properties manually in every property setter like OnPropertyChanged("some-property-name") . Instead you just call OnPropertyChanged() without parameters:

You need .NET 4.5 minimum. CallerMemberName is in the System.Runtime.CompilerServices namespace

public class Sample : INotifyPropertyChanged
{
    private string _propString;
    private int _propInt;


    //======================================
    // Actual implementation
    //======================================
    public event PropertyChangedEventHandler PropertyChanged;

    [NotifyPropertyChangedInvocator]
    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        var handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }
    //======================================
    // END: actual implementation
    //======================================


    public string PropString
    {
        get { return _propString; }
        set
        {
            // do not trigger change event if values are the same
            if (Equals(value, _propString)) return;
            _propString = value;

            //===================
            // Usage in the Source
            //===================
            OnPropertyChanged();

        }
    }

    public int PropInt
    {
        get { return _propInt; }
        set
        {
            // do not allow negative numbers, but always trigger a change event
            _propInt = value < 0 ? 0 : value;
            OnPropertyChanged();
        }
    }
}

Usage stays the same:

var source = new Sample();
textbox.DataBindings.Add("Text", source, "PropString");
source.PropString = "Some new string";

Hope this helps someone.