This class represents a mapping of a property (or column) in a data
source to a property on a Control. In the case of
simple binding, it uses a bag of Binding objects
to handle those mappings. For complex data binding, you can derive a
class that handles the data-binding process.
Each binding manager maintains a current Position
in the data source, to allow multiple bound controls to remain in
sync, each control displaying a different column in the same selected
row.
For example, a ListBox and a
TextBox can be bound to a data source with same
binding manager (simple binding for the TextBox
providing a Binding object, complex binding for
the ListBox without an explicit binding object).
The two will remain synchronized as the ListBox
selection changes. Another ListBox and
TextBox bound to the same data source but through
a second binding manager will also remain synchronized with one
another, but will not be synchronized with the first pair. (See
BindingContext to find out how to create an
independent binding manager for your second pair of controls.)
If the current row in the data source changes, the binding manager
raises PositionChanged. If the value of the bound
object changes, the CurrentChanged event is
raised. See CurrencyManager for information about
how this works in practice, and Binding for more
information about the data-binding hierarchy.
public abstract class BindingManagerBase {
// Public Constructors
public BindingManagerBase();
// Protected Instance Fields
protected EventHandler onCurrentChangedHandler;
protected EventHandler onPositionChangedHandler;
// Public Instance Properties
public BindingsCollection Bindings{get; }
public abstract int Count{get; }
public abstract object Current{get; }
public abstract int Position{set; get; }
// Public Instance Methods
public abstract void AddNew();
public abstract void CancelCurrentEdit();
public abstract void EndCurrentEdit();
public abstract PropertyDescriptorCollection GetItemProperties();
public abstract void RemoveAt(int index);
public abstract void ResumeBinding();
public abstract void SuspendBinding();
// Protected Instance Methods
protected internal virtual PropertyDescriptorCollection GetItemProperties(System.Collections.ArrayList dataSources,
System.Collections.ArrayList listAccessors);
protected virtual PropertyDescriptorCollection GetItemProperties(Type listType, int offset,
System.Collections.ArrayList dataSources, System.Collections.ArrayList listAccessors);
protected internal abstract string GetListName(System.Collections.ArrayList listAccessors);
protected internal abstract void OnCurrentChanged(EventArgs e);
protected void PullData();
protected void PushData();
protected abstract void UpdateIsBinding();
// Events
public event EventHandler CurrentChanged;
public event EventHandler PositionChanged;
}
