internal static object DoConversionFrom(TypeConverter converter, object value)
{
object returnValue = value;
try
{
if (converter != null && value != null && converter.CanConvertFrom(value.GetType()))
{
// This utility class is used to convert value that come from XAML, so we should use the invariant culture.
returnValue = converter.ConvertFrom(context: null, culture: CultureInfo.InvariantCulture, value: value);
}
}
catch (Exception e)
{
if (!TypeConverterHelper.ShouldEatException(e))
{
throw;
}
}
return(returnValue);
}
/// <summary>
/// This method evaluates operands.
/// </summary>
/// <param name="leftOperand">Left operand from the LeftOperand property.</param>
/// <param name="operatorType">Operator from Operator property.</param>
/// <param name="rightOperand">Right operand from the RightOperand property.</param>
/// <returns>Returns true if the condition is met; otherwise, returns false.</returns>
internal static bool EvaluateImpl(object leftOperand, ComparisonConditionType operatorType, object rightOperand)
{
bool result = false;
if (leftOperand != null)
{
Type leftType = leftOperand.GetType();
if (rightOperand != null)
{
TypeConverter typeConverter = TypeConverterHelper.GetTypeConverter(leftType);
rightOperand = TypeConverterHelper.DoConversionFrom(typeConverter, rightOperand);
}
}
IComparable leftComparableOperand = leftOperand as IComparable;
IComparable rightComparableOperand = rightOperand as IComparable;
// If both operands are comparable, use arithmetic comparison
if (leftComparableOperand != null && rightComparableOperand != null)
{
return(ComparisonLogic.EvaluateComparable(leftComparableOperand, operatorType, rightComparableOperand));
}
switch (operatorType)
{
case ComparisonConditionType.Equal:
result = object.Equals(leftOperand, rightOperand);
break;
case ComparisonConditionType.NotEqual:
result = !object.Equals(leftOperand, rightOperand);
break;
case ComparisonConditionType.GreaterThan:
case ComparisonConditionType.GreaterThanOrEqual:
case ComparisonConditionType.LessThan:
case ComparisonConditionType.LessThanOrEqual:
if (leftComparableOperand == null && rightComparableOperand == null)
{
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture,
ExceptionStringTable.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,
ExceptionStringTable.InvalidLeftOperand,
leftOperand != null ? leftOperand.GetType().Name : "null",
operatorType.ToString()));
}
else
{
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture,
ExceptionStringTable.InvalidRightOperand,
rightOperand != null ? rightOperand.GetType().Name : "null",
operatorType.ToString()));
}
}
return(result);
}
