Data bound custom control with updating data when changed

Question

I have a question related to Data Binding

If we have class A with some property for example “UserName” and text control T1 bound as follow :

T1.DataBindings.Add("Text",A,"UserName",true,DataSourceUpdateMode.OnPropertyChanged); 

I.e. property will be updated when user edit text

Now if instead of text box we have custom control C1 with control property “ControlProp” ( for example of type MyEnum ) and it is bound to class B with property MyProp of type MyEnum as following :

C1.DataBindings.Add("ControlProp ",B," MyProp",true,DataSourceUpdateMode.OnPropertyChanged); 

The question is : how can be ensured behavior of custom control similar to text box described above , i.e. class B property will be updated when ControlProp changed ? Your help will be very valuable . Tnanks

Answer 1

First, your class B have to implement INotifyPropertyChanged interface. This is the complete code or class B

public class ClassB : System.ComponentModel.INotifyPropertyChanged { private string myprop;

public string MyProp
{
    get
    {
        return myprop;
    }
    set
    {
        if (value != myprop)
        {
            myprop = value;
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs("MyProp"));
            }


        }


    }
}

#region INotifyPropertyChanged Members

public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;

#endregion

}

Then, suposse that your custom control have a label inside, and you want to bind the text of the label with your instance of class B. For example:

public partial class MyCustomControl : UserControl
{
    public MyCustomControl()
    {
        InitializeComponent();
    }

    public string MyCustomProperty
    {
        get
        {
            return label1.Text;
        }
        set
        {
            label1.Text = value;
        }
    }
}

If you bind the property MyProp of class B to MyCustomProperty of your custom control, when you change the property in your object, label1 should change its text.

    ClassB objectB = new ClassB();

    C1.DataBindings.Add("MyCustomProperty", objectB, "MyProp", true, DataSourceUpdateMode.OnPropertyChanged);

    objectB.MyProp = "Text 1";
    objectB.MyProp = "Text 2";

    // The final text is Text2

Answer 2

I think I found the solution : Added Inotifypropertychange to the control definition : public partial class MyCustomControl : UserControl, INotifyPropertyChanged And in the controls property setter I raise the event ( as in Javier Morillo's example )

Thanks to all