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//---------------------------------------------------------------------------
//
// <copyright file="MultiBindingExpression.cs" company="Microsoft">
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
// Description: Defines MultiBindingExpression object, uses a collection of BindingExpressions together.
//
// See spec at http://avalon/connecteddata/Specs/Data%20Binding.mht
//
//---------------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Globalization;
using System.Windows.Threading;
using System.Threading;
using System.Windows.Controls;
using System.Windows.Input; // FocusChangedEvent
using System.Windows.Markup;
using MS.Internal.Controls; // Validation
using MS.Internal.KnownBoxes;
using MS.Internal.Data;
using MS.Utility;
using MS.Internal; // Invariant.Assert
namespace System.Windows.Data
{
/// <summary>
/// Describes a collection of BindingExpressions attached to a single property.
/// The inner BindingExpressions contribute their values to the MultiBindingExpression,
/// which combines/converts them into a resultant final value.
/// In the reverse direction, the target value is tranlated to
/// a set of values that are fed back into the inner BindingExpressions.
/// </summary>
public sealed class MultiBindingExpression: BindingExpressionBase, IDataBindEngineClient
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
/// <summary> Constructor </summary>
private MultiBindingExpression(MultiBinding binding, BindingExpressionBase owner)
: base(binding, owner)
{
int count = binding.Bindings.Count;
// reduce repeated allocations
_tempValues = new object[count];
_tempTypes = new Type[count];
}
//------------------------------------------------------
//
// Interfaces
//
//------------------------------------------------------
void IDataBindEngineClient.TransferValue()
{
TransferValue();
}
void IDataBindEngineClient.UpdateValue()
{
UpdateValue();
}
bool IDataBindEngineClient.AttachToContext(bool lastChance)
{
AttachToContext(lastChance);
return !TransferIsDeferred;
}
void IDataBindEngineClient.VerifySourceReference(bool lastChance)
{
}
void IDataBindEngineClient.OnTargetUpdated()
{
OnTargetUpdated();
}
DependencyObject IDataBindEngineClient.TargetElement
{
get { return !UsingMentor ? TargetElement : Helper.FindMentor(TargetElement); }
}
//------------------------------------------------------
//
// Public Properties
//
//------------------------------------------------------
/// <summary> Binding from which this expression was created </summary>
public MultiBinding ParentMultiBinding { get { return (MultiBinding)ParentBindingBase; } }
/// <summary> List of inner BindingExpression </summary>
public ReadOnlyCollection<BindingExpressionBase> BindingExpressions
{
get { return new ReadOnlyCollection<BindingExpressionBase>(MutableBindingExpressions); }
}
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
/// <summary> Send the current value back to the source(s) </summary>
/// <remarks> Does nothing when binding's Mode is not TwoWay or OneWayToSource </remarks>
public override void UpdateSource()
{
// ultimately, what would be better would be to have a status flag that
// indicates that this MultiBindingExpression has been Detached, as opposed to a
// MultiBindingExpression that doesn't have anything in its BindingExpressions collection
// in the first place. Added to which, there should be distinct error
// messages for both of these error conditions.
if (MutableBindingExpressions.Count == 0)
throw new InvalidOperationException(SR.Get(SRID.BindingExpressionIsDetached));
NeedsUpdate = true; // force update
Update(); // update synchronously
}
/// <summary> Force a data transfer from sources to target </summary>
/// <remarks> Will transfer data even if binding's Mode is OneWay </remarks>
public override void UpdateTarget()
{
// ultimately, what would be better would be to have a status flag that
// indicates that this MultiBindingExpression has been Detached, as opposed to a
// MultiBindingExpression that doesn't have anything in its BindingExpressions collection
// in the first place. Added to which, there should be distinct error
// messages for both of these error conditions.
if (MutableBindingExpressions.Count == 0)
throw new InvalidOperationException(SR.Get(SRID.BindingExpressionIsDetached));
UpdateTarget(true);
}
#region Expression overrides
#endregion Expression overrides
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
internal override bool IsParentBindingUpdateTriggerDefault
{
get { return (ParentMultiBinding.UpdateSourceTrigger == UpdateSourceTrigger.Default); }
}
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
// Create a new BindingExpression from the given Binding description
internal static MultiBindingExpression CreateBindingExpression(DependencyObject d, DependencyProperty dp, MultiBinding binding, BindingExpressionBase owner)
{
FrameworkPropertyMetadata fwMetaData = dp.GetMetadata(d.DependencyObjectType) as FrameworkPropertyMetadata;
if ((fwMetaData != null && !fwMetaData.IsDataBindingAllowed) || dp.ReadOnly)
throw new ArgumentException(SR.Get(SRID.PropertyNotBindable, dp.Name), "dp");
// create the BindingExpression
MultiBindingExpression bindExpr = new MultiBindingExpression(binding, owner);
bindExpr.ResolvePropertyDefaultSettings(binding.Mode, binding.UpdateSourceTrigger, fwMetaData);
return bindExpr;
}
// Attach to things that may require tree context (parent, root, etc.)
void AttachToContext(bool lastChance)
{
DependencyObject target = TargetElement;
if (target == null)
return;
Debug.Assert(ParentMultiBinding.Converter != null || !String.IsNullOrEmpty(EffectiveStringFormat),
"MultiBindingExpression should not exist if its bind does not have a valid converter.");
bool isExtendedTraceEnabled = TraceData.IsExtendedTraceEnabled(this, TraceDataLevel.AttachToContext);
_converter = ParentMultiBinding.Converter;
if (_converter == null && String.IsNullOrEmpty(EffectiveStringFormat))
{
TraceData.Trace(TraceEventType.Error, TraceData.MultiBindingHasNoConverter, ParentMultiBinding);
}
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.AttachToContext(
TraceData.Identify(this),
lastChance ? " (last chance)" : String.Empty));
}
TransferIsDeferred = true;
bool attached = true; // true if all child bindings have attached
int count = MutableBindingExpressions.Count;
for (int i = 0; i < count; ++i)
{
if (MutableBindingExpressions[i].StatusInternal == BindingStatusInternal.Unattached)
attached = false;
}
// if the child bindings aren't ready yet, try again later. Leave
// TransferIsDeferred set, to indicate we're not ready yet.
if (!attached && !lastChance)
{
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.ChildNotAttached(
TraceData.Identify(this)));
}
return;
}
// listen to the Language property, if needed
if (UsesLanguage)
{
WeakDependencySource[] commonSources = new WeakDependencySource[] { new WeakDependencySource(TargetElement, FrameworkElement.LanguageProperty) };
WeakDependencySource[] newSources = CombineSources(-1, MutableBindingExpressions, MutableBindingExpressions.Count, null, commonSources);
ChangeSources(newSources);
}
// initial transfer
bool initialTransferIsUpdate = IsOneWayToSource;
object currentValue;
if (ShouldUpdateWithCurrentValue(target, out currentValue))
{
initialTransferIsUpdate = true;
ChangeValue(currentValue, /*notify*/false);
NeedsUpdate = true;
}
SetStatus(BindingStatusInternal.Active);
if (!initialTransferIsUpdate)
{
UpdateTarget(false);
}
else
{
UpdateValue();
}
}
//------------------------------------------------------
//
// Public Properties
//
//------------------------------------------------------
/// <summary>
/// The ValidationError that caused this
/// BindingExpression to be invalid.
/// </summary>
public override ValidationError ValidationError
{
get
{
ValidationError validationError = base.ValidationError;
if (validationError == null)
{
for ( int i = 0; i < MutableBindingExpressions.Count; i++ )
{
validationError = MutableBindingExpressions[i].ValidationError;
if (validationError != null)
break;
}
}
return validationError;
}
}
/// <summary>
/// HasError returns true if any of the ValidationRules
/// of any of its inner bindings failed its validation rule
/// or the Multi-/PriorityBinding itself has a failing validation rule.
/// </summary>
public override bool HasError
{
get
{
bool hasError = base.HasError;
if (!hasError)
{
for ( int i = 0; i < MutableBindingExpressions.Count; i++ )
{
if (MutableBindingExpressions[i].HasError)
return true;
}
}
return hasError;
}
}
/// <summary>
/// HasValidationError returns true if any of the ValidationRules
/// of any of its inner bindings failed its validation rule
/// or the Multi-/PriorityBinding itself has a failing validation rule.
/// </summary>
public override bool HasValidationError
{
get
{
bool hasError = base.HasValidationError;
if (!hasError)
{
for ( int i = 0; i < MutableBindingExpressions.Count; i++ )
{
if (MutableBindingExpressions[i].HasValidationError)
return true;
}
}
return hasError;
}
}
//------------------------------------------------------
//
// Protected Internal Methods
//
//------------------------------------------------------
/// <summary>
/// Attach a BindingExpression to the given target (element, property)
/// </summary>
/// <param name="d">DependencyObject being set</param>
/// <param name="dp">Property being set</param>
internal override bool AttachOverride(DependencyObject d, DependencyProperty dp)
{
if (!base.AttachOverride(d, dp))
return false;
DependencyObject target = TargetElement;
if (target == null)
return false;
// listen for lost focus
if (IsUpdateOnLostFocus)
{
LostFocusEventManager.AddHandler(target, OnLostFocus);
}
TransferIsDeferred = true; // Defer data transfer until after we activate all the BindingExpressions
int count = ParentMultiBinding.Bindings.Count;
for (int i = 0; i < count; ++i)
{
// ISSUE: It may be possible to have _attachedBindingExpressions be non-zero
// at the end of Detach if the conditions for the increment on Attach
// and the decrement on Detach are not precisely the same.
AttachBindingExpression(i, false); // create new binding and have it added to end
}
// attach to things that need tree context. Do it synchronously
// if possible, otherwise post a task. This gives the parser et al.
// a chance to assemble the tree before we start walking it.
AttachToContext(false /* lastChance */);
if (TransferIsDeferred)
{
Engine.AddTask(this, TaskOps.AttachToContext);
if (TraceData.IsExtendedTraceEnabled(this, TraceDataLevel.AttachToContext))
{
TraceData.Trace(TraceEventType.Warning,
TraceData.DeferAttachToContext(
TraceData.Identify(this)));
}
}
return true;
}
/// <summary> sever all connections </summary>
internal override void DetachOverride()
{
DependencyObject target = TargetElement;
if (target != null && IsUpdateOnLostFocus)
{
LostFocusEventManager.RemoveHandler(target, OnLostFocus);
}
// Theoretically, we only need to detach number of AttentiveBindingExpressions,
// but we'll traverse the whole list anyway and do aggressive clean-up.
int count = MutableBindingExpressions.Count;
for (int i = count - 1; i >= 0; i--)
{
BindingExpressionBase b = MutableBindingExpressions[i];
if (b != null)
{
b.Detach();
MutableBindingExpressions.RemoveAt(i);
}
}
ChangeSources(null);
base.DetachOverride();
}
/// <summary>
/// Invalidate the given child expression.
/// </summary>
internal override void InvalidateChild(BindingExpressionBase bindingExpression)
{
int index = MutableBindingExpressions.IndexOf(bindingExpression);
// do a sanity check that we care about this BindingExpression
if (0 <= index && IsDynamic)
{
NeedsDataTransfer = true;
Transfer(); // this will Invalidate target property.
}
}
/// <summary>
/// Change the dependency sources for the given child expression.
/// </summary>
internal override void ChangeSourcesForChild(BindingExpressionBase bindingExpression, WeakDependencySource[] newSources)
{
int index = MutableBindingExpressions.IndexOf(bindingExpression);
if (index >= 0)
{
WeakDependencySource[] commonSources = null;
if (UsesLanguage)
{
commonSources = new WeakDependencySource[] { new WeakDependencySource(TargetElement, FrameworkElement.LanguageProperty) };
}
WeakDependencySource[] combinedSources = CombineSources(index, MutableBindingExpressions, MutableBindingExpressions.Count, newSources, commonSources);
ChangeSources(combinedSources);
}
}
/// <summary>
/// Replace the given child expression with a new one.
/// </summary>
internal override void ReplaceChild(BindingExpressionBase bindingExpression)
{
int index = MutableBindingExpressions.IndexOf(bindingExpression);
DependencyObject target = TargetElement;
if (index >= 0 && target != null)
{
// detach and clean up the old binding
bindingExpression.Detach();
// replace BindingExpression
AttachBindingExpression(index, true);
}
}
// register the leaf bindings with the binding group
internal override void UpdateBindingGroup(BindingGroup bg)
{
for (int i=0, n=MutableBindingExpressions.Count-1; i<n; ++i)
{
MutableBindingExpressions[i].UpdateBindingGroup(bg);
}
}
/// <summary>
/// Get the converted proposed value
/// <summary>
internal override object ConvertProposedValue(object value)
{
object result;
bool success = ConvertProposedValueImpl(value, out result);
// if the conversion failed, signal a validation error
if (!success)
{
result = DependencyProperty.UnsetValue;
ValidationError validationError = new ValidationError(ConversionValidationRule.Instance, this, SR.Get(SRID.Validation_ConversionFailed, value), null);
UpdateValidationError(validationError);
}
return result;
}
private bool ConvertProposedValueImpl(object value, out object result)
{
DependencyObject target = TargetElement;
if (target == null)
{
result = DependencyProperty.UnsetValue;
return false;
}
result = GetValuesForChildBindings(value);
if (IsDetached)
{
return false; // user code detached the binding. give up.
}
if (result == DependencyProperty.UnsetValue)
{
SetStatus(BindingStatusInternal.UpdateSourceError);
return false;
}
object[] values = (object[])result;
if (values == null)
{
if (TraceData.IsEnabled)
{
TraceData.Trace(TraceEventType.Error,
TraceData.BadMultiConverterForUpdate(
Converter.GetType().Name,
AvTrace.ToStringHelper(value),
AvTrace.TypeName(value)),
this);
}
result = DependencyProperty.UnsetValue;
return false;
}
if (TraceData.IsExtendedTraceEnabled(this, TraceDataLevel.Update))
{
for (int i=0; i<values.Length; ++i)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.UserConvertBackMulti(
TraceData.Identify(this),
i,
TraceData.Identify(values[i])));
}
}
// if lengths are mismatched, show warning
int count = MutableBindingExpressions.Count;
if (values.Length != count && TraceData.IsEnabled)
{
TraceData.Trace(TraceEventType.Information, TraceData.MultiValueConverterMismatch,
Converter.GetType().Name, count, values.Length,
TraceData.DescribeTarget(target, TargetProperty));
}
// use the smaller count
if (values.Length < count)
count = values.Length;
// using the result of ConvertBack as the raw value, run each child binding
// through the first two steps of the update/validate process
bool success = true;
for (int i = 0; i < count; ++i)
{
value = values[i];
if (value != Binding.DoNothing && value != DependencyProperty.UnsetValue)
{
BindingExpressionBase bindExpr = MutableBindingExpressions[i];
bindExpr.SetValue(target, TargetProperty, value); // could pass (null, null, values[i])
value = bindExpr.GetRawProposedValue();
if (!bindExpr.Validate(value, ValidationStep.RawProposedValue))
value = DependencyProperty.UnsetValue;
value = bindExpr.ConvertProposedValue(value);
}
else if (value == DependencyProperty.UnsetValue && TraceData.IsEnabled)
{
TraceData.Trace(TraceEventType.Information,
TraceData.UnsetValueInMultiBindingExpressionUpdate(
Converter.GetType().Name,
AvTrace.ToStringHelper(value),
i,
_tempTypes[i]
),
this);
}
if (value == DependencyProperty.UnsetValue)
{
success = false;
}
values[i] = value;
}
Array.Clear(_tempTypes, 0, _tempTypes.Length);
result = values;
return success;
}
object GetValuesForChildBindings(object rawValue)
{
if (Converter == null)
{
if (TraceData.IsEnabled)
{
TraceData.Trace(TraceEventType.Error, TraceData.MultiValueConverterMissingForUpdate, this);
}
return DependencyProperty.UnsetValue;
}
CultureInfo culture = GetCulture();
int count = MutableBindingExpressions.Count;
for (int i = 0; i < count; ++i)
{
BindingExpressionBase bindExpr = MutableBindingExpressions[i];
BindingExpression be = bindExpr as BindingExpression;
if (be != null && be.UseDefaultValueConverter)
_tempTypes[i] = be.ConverterSourceType;
else
_tempTypes[i] = TargetProperty.PropertyType;
}
// MultiValueConverters are always user-defined, so don't catch exceptions (bug 992237)
return Converter.ConvertBack(rawValue, _tempTypes, ParentMultiBinding.ConverterParameter, culture);
}
/// <summary>
/// Get the converted proposed value and inform the binding group
/// <summary>
internal override bool ObtainConvertedProposedValue(BindingGroup bindingGroup)
{
bool result = true;
if (NeedsUpdate)
{
object value = bindingGroup.GetValue(this);
if (value != DependencyProperty.UnsetValue)
{
object[] values;
value = ConvertProposedValue(value);
if (value == DependencyProperty.UnsetValue)
{
result = false;
}
else if ((values = value as object[]) != null)
{
for (int i=0; i<values.Length; ++i)
{
if (values[i] == DependencyProperty.UnsetValue)
{
result = false;
}
}
}
}
StoreValueInBindingGroup(value, bindingGroup);
}
else
{
bindingGroup.UseSourceValue(this);
}
return result;
}
/// <summary>
/// Update the source value
/// <summary>
internal override object UpdateSource(object convertedValue)
{
if (convertedValue == DependencyProperty.UnsetValue)
{
SetStatus(BindingStatusInternal.UpdateSourceError);
return convertedValue;
}
object[] values = convertedValue as object[];
int count = MutableBindingExpressions.Count;
if (values.Length < count)
count = values.Length;
BeginSourceUpdate();
bool updateActuallyHappened = false;
for (int i = 0; i < count; ++i)
{
object value = values[i];
if (value != Binding.DoNothing)
{
BindingExpressionBase bindExpr = MutableBindingExpressions[i];
bindExpr.UpdateSource(value);
if (bindExpr.StatusInternal == BindingStatusInternal.UpdateSourceError)
{
SetStatus(BindingStatusInternal.UpdateSourceError);
}
updateActuallyHappened = true;
}
}
if (!updateActuallyHappened)
{
IsInUpdate = false; // inhibit the "$10 bug" re-fetch if nothing actually updated
}
EndSourceUpdate();
OnSourceUpdated();
return convertedValue;
}
/// <summary>
/// Update the source value and inform the binding group
/// <summary>
internal override bool UpdateSource(BindingGroup bindingGroup)
{
bool result = true;
if (NeedsUpdate)
{
object value = bindingGroup.GetValue(this);
UpdateSource(value);
if (value == DependencyProperty.UnsetValue)
{
result = false;
}
}
return result;
}
/// <summary>
/// Store the value in the binding group
/// </summary>
internal override void StoreValueInBindingGroup(object value, BindingGroup bindingGroup)
{
bindingGroup.SetValue(this, value);
object[] values = value as object[];
if (values != null)
{
int count = MutableBindingExpressions.Count;
if (values.Length < count)
count = values.Length;
for (int i=0; i<count; ++i)
{
MutableBindingExpressions[i].StoreValueInBindingGroup(values[i], bindingGroup);
}
}
else
{
for (int i=MutableBindingExpressions.Count-1; i>=0; --i)
{
MutableBindingExpressions[i].StoreValueInBindingGroup(DependencyProperty.UnsetValue, bindingGroup);
}
}
}
/// <summary>
/// Run validation rules for the given step
/// <summary>
internal override bool Validate(object value, ValidationStep validationStep)
{
if (value == Binding.DoNothing)
return true;
if (value == DependencyProperty.UnsetValue)
{
SetStatus(BindingStatusInternal.UpdateSourceError);
return false;
}
// run rules attached to this multibinding
bool result = base.Validate(value, validationStep);
// run rules attached to the child bindings
switch (validationStep)
{
case ValidationStep.RawProposedValue:
// the child bindings don't get raw values until the Convert step
break;
default:
object[] values = value as object[];
int count = MutableBindingExpressions.Count;
if (values.Length < count)
count = values.Length;
for (int i=0; i<count; ++i)
{
value = values[i];
if (value == DependencyProperty.UnsetValue)
{
// an unset value means the binding failed validation at an earlier step,
// typically at Raw step, evaluated during the MultiBinding's ConvertValue
//result = false;
// COMPAT: This should mean the MultiBinding as a whole fails validation, but
// in 3.5 this didn't happen. Instead the process continued, writing back
// values to child bindings that succeeded, and simply not writing back
// to child bindings that didn't.
}
else if (value != Binding.DoNothing)
{
if (!MutableBindingExpressions[i].Validate(value, validationStep))
{
values[i] = DependencyProperty.UnsetValue; // prevent writing an invalid value
//result = false;
// COMPAT: as above, preserve v3.5 behavior by not failing when a
// child binding fails to validate
}
}
}
break;
}
return result;
}
/// <summary>
/// Run validation rules for the given step, and inform the binding group
/// <summary>
internal override bool CheckValidationRules(BindingGroup bindingGroup, ValidationStep validationStep)
{
if (!NeedsValidation)
return true;
object value;
switch (validationStep)
{
case ValidationStep.RawProposedValue:
case ValidationStep.ConvertedProposedValue:
case ValidationStep.UpdatedValue:
case ValidationStep.CommittedValue:
value = bindingGroup.GetValue(this);
break;
default:
throw new InvalidOperationException(SR.Get(SRID.ValidationRule_UnknownStep, validationStep, bindingGroup));
}
bool result = Validate(value, validationStep);
if (result && validationStep == ValidationStep.CommittedValue)
{
NeedsValidation = false;
}
return result;
}
/// <summary>
/// Get the proposed value(s) that would be written to the source(s), applying
/// conversion and checking UI-side validation rules.
/// </summary>
internal override bool ValidateAndConvertProposedValue(out Collection<ProposedValue> values)
{
Debug.Assert(NeedsValidation, "check NeedsValidation before calling this");
values = null;
// validate raw proposed value
object rawValue = GetRawProposedValue();
bool isValid = Validate(rawValue, ValidationStep.RawProposedValue);
if (!isValid)
{
return false;
}
// apply conversion
object conversionResult = GetValuesForChildBindings(rawValue);
if (IsDetached || conversionResult == DependencyProperty.UnsetValue || conversionResult == null)
{
return false;
}
int count = MutableBindingExpressions.Count;
object[] convertedValues = (object[])conversionResult;
if (convertedValues.Length < count)
count = convertedValues.Length;
values = new Collection<ProposedValue>();
bool result = true;
// validate child bindings
for (int i = 0; i < count; ++i)
{
object value = convertedValues[i];
if (value == Binding.DoNothing)
{
}
else if (value == DependencyProperty.UnsetValue)
{
// conversion failure
result = false;
}
else
{
// send converted value to child binding
BindingExpressionBase bindExpr = MutableBindingExpressions[i];
bindExpr.Value = value;
// validate child binding
if (bindExpr.NeedsValidation)
{
Collection<ProposedValue> childValues;
bool childResult = bindExpr.ValidateAndConvertProposedValue(out childValues);
// append child's values to our values
if (childValues != null)
{
for (int k=0, n=childValues.Count; k<n; ++k)
{
values.Add(childValues[k]);
}
}
// merge child's result
result = result && childResult;
}
}
}
return result;
}
// Return the object from which the given value was obtained, if possible
internal override object GetSourceItem(object newValue)
{
if (newValue == null)
return null; // this avoids false positive results
// It's impossible to find the source item in the general case - the value
// may have been produced by the multi-converter, combining inputs from
// several different sources. But we can do it in the special case where
// one of the child bindings actually produced the final value, and the
// converter merely selected it (or did other extraneous work).
int count = MutableBindingExpressions.Count;
for (int i = 0; i < count; ++i)
{
object value = MutableBindingExpressions[i].GetValue(null, null); // could pass (null, null)
if (ItemsControl.EqualsEx(value, newValue))
return MutableBindingExpressions[i].GetSourceItem(newValue);
}
return null;
}
//------------------------------------------------------
//
// Private Properties
//
//------------------------------------------------------
/// <summary>
/// expose a mutable version of the list of all BindingExpressions;
/// derived internal classes need to be able to populate this list
/// </summary>
private Collection<BindingExpressionBase> MutableBindingExpressions
{
get { return _list; }
}
IMultiValueConverter Converter
{
get { return _converter; }
set { _converter = value; }
}
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
// Create a BindingExpression for position i
BindingExpressionBase AttachBindingExpression(int i, bool replaceExisting)
{
DependencyObject target = TargetElement;
if (target == null)
return null;
BindingBase binding = ParentMultiBinding.Bindings[i];
// Check if replacement bindings have the correct UpdateSourceTrigger
MultiBinding.CheckTrigger(binding);
BindingExpressionBase bindExpr = binding.CreateBindingExpression(target, TargetProperty, this);
if (replaceExisting) // replace exisiting or add as new binding?
MutableBindingExpressions[i] = bindExpr;
else
MutableBindingExpressions.Add(bindExpr);
bindExpr.Attach(target, TargetProperty);
return bindExpr;
}
internal override void HandlePropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args)
{
DependencyProperty dp = args.Property;
if (TraceData.IsExtendedTraceEnabled(this, TraceDataLevel.Events))
{
TraceData.Trace(TraceEventType.Warning,
TraceData.GotPropertyChanged(
TraceData.Identify(this),
TraceData.Identify(d),
dp.Name));
}
bool isConnected = true;
TransferIsDeferred = true;
if (UsesLanguage && d == TargetElement && dp == FrameworkElement.LanguageProperty)
{
InvalidateCulture();
NeedsDataTransfer = true; // force a transfer - it will honor the new culture
}
// if the binding has been detached (by the reference to TargetElement), quit now
if (IsDetached)
return;
int n = MutableBindingExpressions.Count;
for (int i = 0; i < n; ++i)
{
BindingExpressionBase bindExpr = MutableBindingExpressions[i];
if (bindExpr != null)
{
DependencySource[] sources = bindExpr.GetSources();
if (sources != null)
{
for (int j = 0; j < sources.Length; ++j)
{
DependencySource source = sources[j];
if (source.DependencyObject == d && source.DependencyProperty == dp)
{
bindExpr.OnPropertyInvalidation(d, args);
break;
}
}
}
if (bindExpr.IsDisconnected)
{
isConnected = false;
}
}
}
TransferIsDeferred = false;
if (isConnected)
{
Transfer(); // Transfer if inner BindingExpressions have called Invalidate(binding)
}
else
{
Disconnect();
}
}
/// <summary>
/// Handle events from the centralized event table
/// </summary>
internal override bool ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
{
return false; // this method is no longer used (but must remain, for compat)
}
internal override void OnLostFocus(object sender, RoutedEventArgs e)
{
if (TraceData.IsExtendedTraceEnabled(this, TraceDataLevel.Events))
{
TraceData.Trace(TraceEventType.Warning,
TraceData.GotEvent(
TraceData.Identify(this),
"LostFocus",
TraceData.Identify(sender)));
}
Update();
}
#region Value
/// <summary> Force a data transfer from source(s) to target </summary>
/// <param name="includeInnerBindings">
/// use true to propagate UpdateTarget call to all inner BindingExpressions;
/// use false to avoid forcing data re-transfer from one-time inner BindingExpressions
/// </param>
void UpdateTarget(bool includeInnerBindings)
{
TransferIsDeferred = true;
if (includeInnerBindings)
{
foreach (BindingExpressionBase b in MutableBindingExpressions)
{
b.UpdateTarget();
}
}
TransferIsDeferred = false;
NeedsDataTransfer = true; // force data transfer
Transfer();
NeedsUpdate = false;
}
// transfer a value from the source to the target
void Transfer()
{
// required state for transfer
if ( NeedsDataTransfer // Transfer is needed
&& StatusInternal != BindingStatusInternal.Unattached // All bindings are attached
&& !TransferIsDeferred) // Not aggregating transfers
{
TransferValue();
}
}
// transfer a value from the source to the target
void TransferValue()
{
IsInTransfer = true;
NeedsDataTransfer = false;
DependencyObject target = TargetElement;
if (target == null)
goto Done;
bool isExtendedTraceEnabled = TraceData.IsExtendedTraceEnabled(this, TraceDataLevel.Transfer);
object value = DependencyProperty.UnsetValue;
object preFormattedValue = _tempValues;
CultureInfo culture = GetCulture();
// gather values from inner BindingExpressions
int count = MutableBindingExpressions.Count;
for (int i = 0; i < count; ++i)
{
_tempValues[i] = MutableBindingExpressions[i].GetValue(target, TargetProperty); // could pass (null, null)
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.GetRawValueMulti(
TraceData.Identify(this),
i,
TraceData.Identify(_tempValues[i])));
}
}
// apply the converter
if (Converter != null)
{
// MultiValueConverters are always user-defined, so don't catch exceptions (bug 992237)
preFormattedValue = Converter.Convert(_tempValues, TargetProperty.PropertyType, ParentMultiBinding.ConverterParameter, culture);
if (IsDetached)
{
// user code detached the binding. Give up.
return;
}
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.UserConverter(
TraceData.Identify(this),
TraceData.Identify(preFormattedValue)));
}
}
else if (EffectiveStringFormat != null)
{
// preFormattedValue = _tempValues;
// But check for child binding conversion errors
for (int i=0; i<_tempValues.Length; ++i)
{
if (_tempValues[i] == DependencyProperty.UnsetValue)
{
preFormattedValue = DependencyProperty.UnsetValue;
break;
}
}
}
else // no converter (perhaps user specified it in error)
{
if (TraceData.IsEnabled)
{
TraceData.Trace(TraceEventType.Error, TraceData.MultiValueConverterMissingForTransfer, this);
}
goto Done;
}
// apply string formatting
if (EffectiveStringFormat == null || preFormattedValue == Binding.DoNothing || preFormattedValue == DependencyProperty.UnsetValue)
{
value = preFormattedValue;
}
else
{
try
{
// we call String.Format either with multiple values (obtained from
// the child bindings) or a single value (as produced by the converter).
// The if-test is needed to avoid wrapping _tempValues inside another object[].
if (preFormattedValue == _tempValues)
{
value = String.Format(culture, EffectiveStringFormat, _tempValues);
}
else
{
value = String.Format(culture, EffectiveStringFormat, preFormattedValue);
}
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.FormattedValue(
TraceData.Identify(this),
TraceData.Identify(value)));
}
}
catch (FormatException)
{
// formatting didn't work
value = DependencyProperty.UnsetValue;
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.FormattingFailed(
TraceData.Identify(this),
EffectiveStringFormat));
}
}
}
Array.Clear(_tempValues, 0, _tempValues.Length);
// the special value DoNothing means no error, but no data transfer
if (value == Binding.DoNothing)
goto Done;
// ultimately, TargetNullValue should get assigned implicitly,
// even if the user doesn't declare it. We can't do this yet because
// of back-compat. I wrote it both ways, and #if'd out the breaking
// change.
#if TargetNullValueBC //BreakingChange
if (IsNullValue(value))
#else
if (EffectiveTargetNullValue != DependencyProperty.UnsetValue &&
IsNullValue(value))
#endif
{
value = EffectiveTargetNullValue;
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.NullConverter(
TraceData.Identify(this),
TraceData.Identify(value)));
}
}
// if the value isn't acceptable to the target property, don't use it
if (value != DependencyProperty.UnsetValue && !TargetProperty.IsValidValue(value))
{
if (TraceData.IsEnabled)
{
TraceData.Trace(TraceLevel, TraceData.BadValueAtTransfer, value, this);
}
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.BadValueAtTransferExtended(
TraceData.Identify(this),
TraceData.Identify(value)));
}
value = DependencyProperty.UnsetValue;
}
// if we can't obtain a value, try the fallback value.
if (value == DependencyProperty.UnsetValue)
{
value = UseFallbackValue();
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.UseFallback(
TraceData.Identify(this),
TraceData.Identify(value)));
}
}
if (isExtendedTraceEnabled)
{
TraceData.Trace(TraceEventType.Warning,
TraceData.TransferValue(
TraceData.Identify(this),
TraceData.Identify(value)));
}
// if this is a re-transfer after a source update and the value
// hasn't changed, don't do any more work.
bool realTransfer = !(IsInUpdate && ItemsControl.EqualsEx(value, Value));
if (realTransfer)
{
// update the cached value
ChangeValue(value, true);
// push the new value through the property engine
Invalidate(false);
Validation.ClearInvalid(this);
}
// after updating all the state (value, validation), mark the binding clean
Clean();
if (realTransfer)
{
OnTargetUpdated();
}
Done:
IsInTransfer = false;
}
void OnTargetUpdated()
{
if (NotifyOnTargetUpdated)
{
DependencyObject target = TargetElement;
if (target != null)
{
// while attaching a normal (not style-defined) BindingExpression,
// we must defer raising the event until after the
// property has been invalidated, so that the event handler
// gets the right value if it asks (bug 1036862)
if (IsAttaching && this == target.ReadLocalValue(TargetProperty))
{
Engine.AddTask(this, TaskOps.RaiseTargetUpdatedEvent);
}
else
{
BindingExpression.OnTargetUpdated(target, TargetProperty);
}
}
}
}
void OnSourceUpdated()
{
if (NotifyOnSourceUpdated)
{
DependencyObject target = TargetElement;
if (target != null)
{
BindingExpression.OnSourceUpdated(target, TargetProperty);
}
}
}
internal override bool ShouldReactToDirtyOverride()
{
// react only if all the child bindings should react
foreach (BindingExpressionBase beb in MutableBindingExpressions)
{
if (!beb.ShouldReactToDirtyOverride())
{
return false;
}
}
return true;
}
// transfer a value from the target to the source
internal override bool UpdateOverride()
{
// various reasons not to update:
if ( !NeedsUpdate // nothing to do
|| !IsReflective // no update desired
|| IsInTransfer // in a transfer
|| StatusInternal == BindingStatusInternal.Unattached // not ready yet
)
return true;
return UpdateValue();
}
#endregion Value
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
Collection<BindingExpressionBase> _list = new Collection<BindingExpressionBase>();
IMultiValueConverter _converter;
object[] _tempValues;
Type[] _tempTypes;
}
}
|