// Comparison is the most nested level
protected override void Visit(ComparisonExpression exp)
{
var model = new ComparisonModel
{
ParamName = exp.Param.ParamName,
Value = exp.Value.Value,
Operator = exp.Operator
};
var op = _comparisonOperators.Find(exp.Operator);
if (op != null)
{
model.OperatorDisplayName = op.Name;
if (!String.IsNullOrWhiteSpace(op.Alias))
{
model.OperatorDisplayName = op.Alias;
}
}
var param = _parameters.Find(x => x.Name.Equals(model.ParamName, StringComparison.OrdinalIgnoreCase));
if (param != null)
{
model.ValueType = param.ValueType.FullName;
model.IsNumberValue = param.ValueType.IsNumericType();
}
_stack.Push(model);
}
protected override void Visit(ComparisonExpression exp)
{
var paramName = exp.Param.ParamName;
var param = _availableParameters.FirstOrDefault(x => x.Name == paramName);
if (param == null)
{
throw new UnrecognizedParameterException("Unrecognized parameter \"" + paramName + "\" or it's not accessable in currect context.");
}
var @operator = _comparisonOperators.Find(exp.Operator);
if (@operator == null)
{
throw new UnrecognizedComparisonOperatorException("Unrecognized comparison operator \"" + exp.Operator + "\".");
}
var result = false;
var paramValue = param.ResolveValue(_dataContext);
if (paramValue != null)
{
var paramType = paramValue.GetType();
object conditionValue = null;
if (paramType.IsEnum)
{
conditionValue = Enum.Parse(paramType, exp.Value.Value);
}
else
{
conditionValue = Convert.ChangeType(exp.Value.Value, paramType);
}
result = @operator.Apply(param, paramValue, conditionValue);
}
_results.Push(result);
}
