//---------------------------------------------------------------------------
//
// <copyright file="BindingWorker.cs" company="Microsoft">
//    Copyright (C) Microsoft Corporation.  All rights reserved.
// </copyright>
//
// Description: Defines BindingWorker base class.
//
//---------------------------------------------------------------------------
 
using System;
using System.Diagnostics;
using System.Reflection;
using System.ComponentModel;
 
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Threading;
 
 
namespace MS.Internal.Data
{
 
    // Base class for binding workers.
    // Derived classes implement binding functionality depending on the
    // type of source, e.g.  ClrBindingWorker, XmlBindingWorker
    internal abstract class BindingWorker
    {
        //------------------------------------------------------
        //
        //  Constructors
        //
        //------------------------------------------------------
        static BindingWorker()
        {
            Debug.Assert((int)Feature.LastFeatureId <= 32, "UncommonValueTable supports only 32 Ids");
        }
 
        protected BindingWorker(BindingExpression b)
        {
            _bindingExpression = b;
        }
 
        //------------------------------------------------------
        //
        //  Internal properties - used by parent BindingExpression
        //
        //------------------------------------------------------
 
        internal virtual Type           SourcePropertyType      { get { return null; } }
        internal virtual bool           CanUpdate               { get { return false; } }
        internal BindingExpression      ParentBindingExpression { get { return _bindingExpression; } }
        internal Type                   TargetPropertyType      { get { return TargetProperty.PropertyType; } }
        internal virtual bool           IsDBNullValidForUpdate  { get { return false; } }
        internal virtual object         SourceItem              { get { return null; } }
        internal virtual string         SourcePropertyName      { get { return null; } }
 
        //------------------------------------------------------
        //
        //  Internal methods - used by parent BindingExpression
        //
        //------------------------------------------------------
 
        internal virtual void           AttachDataItem()        {}
        internal virtual void           DetachDataItem()        {}
        internal virtual void           OnCurrentChanged(ICollectionView collectionView, EventArgs args) {}
        internal virtual object         RawValue()              { return null; }
        internal virtual void           UpdateValue(object value) {}
        internal virtual void           RefreshValue()          {}
        internal virtual bool           UsesDependencyProperty(DependencyObject d, DependencyProperty dp) { return false; }
        internal virtual void           OnSourceInvalidation(DependencyObject d, DependencyProperty dp, bool isASubPropertyChange) {}
        internal virtual bool           IsPathCurrent()         { return true; }
 
        //------------------------------------------------------
        //
        //  Protected Properties
        //
        //------------------------------------------------------
 
        protected Binding      ParentBinding          { get { return ParentBindingExpression.ParentBinding; } }
 
        protected bool      IsDynamic           { get { return ParentBindingExpression.IsDynamic; } }
        internal  bool      IsReflective        { get { return ParentBindingExpression.IsReflective; } }
        protected bool      IgnoreSourcePropertyChange { get { return ParentBindingExpression.IgnoreSourcePropertyChange; } }
        protected object    DataItem            { get { return ParentBindingExpression.DataItem; } }
        protected DependencyObject TargetElement { get { return ParentBindingExpression.TargetElement; } }
        protected DependencyProperty TargetProperty { get { return ParentBindingExpression.TargetProperty; } }
        protected DataBindEngine Engine         { get { return ParentBindingExpression.Engine; } }
        protected Dispatcher Dispatcher         { get { return ParentBindingExpression.Dispatcher; } }
 
        protected BindingStatusInternal Status
        {
            get { return ParentBindingExpression.StatusInternal; }
            set { ParentBindingExpression.SetStatus(value); }
        }
 
        //------------------------------------------------------
        //
        //  Protected Methods
        //
        //------------------------------------------------------
 
        protected void SetTransferIsPending(bool value)
        {
            ParentBindingExpression.IsTransferPending = value;
        }
 
        //------------------------------------------------------
        //
        //  Private Fields
        //
        //------------------------------------------------------
 
        BindingExpression _bindingExpression;
 
        #region Uncommon Values
 
        internal enum Feature
        {
            // ClrBindingWorker
            XmlWorker,
            PendingGetValueRequest,
            PendingSetValueRequest,
 
            // XmlBindingWorker
 
            // Sentinel, for error checking.   Must be last.
            LastFeatureId
        }
 
        internal bool      HasValue(Feature id) { return _values.HasValue((int)id); }
        internal object    GetValue(Feature id, object defaultValue) { return _values.GetValue((int)id, defaultValue); }
        internal void      SetValue(Feature id, object value) { _values.SetValue((int)id, value); }
        internal void      SetValue(Feature id, object value, object defaultValue) { if (Object.Equals(value, defaultValue)) _values.ClearValue((int)id); else _values.SetValue((int)id, value); }
        internal void      ClearValue(Feature id) { _values.ClearValue((int)id); }
        UncommonValueTable  _values;
 
        #endregion Uncommon Values
    }
}