Hi,

When a property changes ( eg. TextChanged/ ReadOnlyChanged ) then the
change(s) aren't persisted back to the DataSource until the Control fires
the Validating event.  This is normal behaviour like it was also in NET1.1.

The above does match your description for the Text property (which isn't
changed from code).  But for the ReadOnly property that is changed from
code, i wonder whether you are changing it from a button event handler,
because in that case TextBox.Validating is fired before the ReadOnly
property is changed, so instead of changing the Text you need to go back to
the TextBox and then leave it again to get another Validating event.

Now there are a couple of ways to alter this behaviour:

1) You can force persisting changed properties back into the DataSource, by
using EndCurrentEdit, it's important to know that only the properties that
have changed will be persisted (unless they don't have a Changed event).

// DataSource and DataMember need to be the same as the ones used for the
Binding.
// DataMember must not include any fieldname/propertyname and can be empty
string
// in which case it may be omitted.
BindingContext(DataSource, DataMember).EndCurrentEdit()
or
BindingContext(DataSource).EndCurrentEdit()

The above will cause something similar to the Validating event.

2) In NET2.0 there is a way to make properties persist back to the
DataSource when the property is changed (*), instead of the default when the
control is Validating:

textBox1.DataBindings.Add("Text", dt, "Desc", false,
DataSourceUpdateMode.OnPropertyChanged);
textBox1.DataBindings.Add("ReadOnly", dt, "DescRO", false,
DataSourceUpdateMode.OnPropertyChanged);

(*) If you add  a property to a Control, then i advise you to add a
<PropertyName>Changed event and fire it when the property has changed.

Public Class MyControl
 Inherits TextBox
 Private mSomeProp As Boolean

 Public Event SomePropChanged As EventHandler

 Public Property SomeProp As Boolean
 Get
   return mSomeProp
 End Get
 Set ( Value As Boolean )
   If ( Value <> mSomeProp )
      mSomeProp = Value
      RaiseEvent SomePropChanged(Me, EventArgs.Empty)
    End If
  End Set
  End Property
End Class

HTH,
Greetings