CODEWITHSUNDEEP
c#.netbinding
lcvinny
lcvinny

Reputation: 300

How to refresh a simple binding of a Windows Forms control?

I'm binding a domain objects property to the Text property of a System.Windows.Forms.Label using the DataBindings:

Label l = new Label();
l.DataBindings.Add(new Binding("Text",myDomainObject,"MyProperty"));

However, when I change the domain object, the Label does not reflect the change. I know that for complex Controls like the DataGridView, binding can be done with a BindingSource on which I can call ResetBindings, but I couldn't find any method to update the binding in the simple case of a Label.

Upvotes: 3

Views: 7213

Answers (2)

Kent Boogaart
Kent Boogaart

Reputation: 178820

Your domain object should implement INotifyPropertyChanged so that the binding knows when the underlying property has changed.

Upvotes: 4

John Alexiou
John Alexiou

Reputation: 29274

Kent has the correct answer, but I want to add a little tidbit on applying INotifyPropertyChanged interface.

To raise the event easily try this

protected void OnPropertyChanged<T>(Expression<Func<T>> property)
{
    if (this.PropertyChanged != null)
    {
        var mex = property.Body as MemberExpression;
        string name = mex.Member.Name;
        this.PropertyChanged(this, new PropertyChangedEventArgs(name));
    }
}

and apply it like

{ // inside some method or property setter
    OnPropertyChanged(() => this.MyProperty);
}

The only reason this is better than specifying the property by name, is that if you refactor, or just change the name of the property you won't have to manually change the implentation, but can let the compiler rename all the references automatically.

Upvotes: 8

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