private static bool Compare(object leftOperand, ComparisonConditionType operatorType, object rightOperand)
{
if (leftOperand != null && rightOperand != null)
{
rightOperand = TypeConverterHelper.Convert(rightOperand.ToString(), leftOperand.GetType().FullName);
}
IComparable leftComparableOperand = leftOperand as IComparable;
IComparable rightComparableOperand = rightOperand as IComparable;
if ((leftComparableOperand != null) && (rightComparableOperand != null))
{
return(DataTriggerBehavior.EvaluateComparable(leftComparableOperand, operatorType, rightComparableOperand));
}
switch (operatorType)
{
case ComparisonConditionType.Equal:
return(object.Equals(leftOperand, rightOperand));
case ComparisonConditionType.NotEqual:
return(!object.Equals(leftOperand, rightOperand));
case ComparisonConditionType.LessThan:
case ComparisonConditionType.LessThanOrEqual:
case ComparisonConditionType.GreaterThan:
case ComparisonConditionType.GreaterThanOrEqual:
{
if (leftComparableOperand == null && rightComparableOperand == null)
{
throw new ArgumentException(string.Format(
CultureInfo.CurrentCulture,
ResourceHelper.InvalidOperands,
leftOperand != null ? leftOperand.GetType().Name : "null",
rightOperand != null ? rightOperand.GetType().Name : "null",
operatorType.ToString()));
}
else if (leftComparableOperand == null)
{
throw new ArgumentException(string.Format(
CultureInfo.CurrentCulture,
ResourceHelper.InvalidLeftOperand,
leftOperand != null ? leftOperand.GetType().Name : "null",
operatorType.ToString()));
}
else
{
throw new ArgumentException(string.Format(
CultureInfo.CurrentCulture,
ResourceHelper.InvalidRightOperand,
rightOperand != null ? rightOperand.GetType().Name : "null",
operatorType.ToString()));
}
}
}
return(false);
}
private static void OnValueChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs args)
{
DataTriggerBehavior dataTriggerBehavior = (DataTriggerBehavior)dependencyObject;
if (dataTriggerBehavior.AssociatedObject == null)
{
return;
}
DataBindingHelper.RefreshDataBindingsOnActions(dataTriggerBehavior.Actions);
// Some value has changed--either the binding value, reference value, or the comparison condition. Re-evaluate the equation.
if (DataTriggerBehavior.Compare(dataTriggerBehavior.Binding, dataTriggerBehavior.ComparisonCondition, dataTriggerBehavior.Value))
{
Interaction.ExecuteActions(dataTriggerBehavior.AssociatedObject, dataTriggerBehavior.Actions, args);
}
}
