public Expression <Func <TItem, bool> > GetPredicate(string identifier)
{
object identifierObj = ConversionUtility.ConvertString(identifier, _propertyInfo.PropertyType);
ParameterExpression param = Expression.Parameter(typeof(TItem), "t");
Expression propertyExpr = Expression.Property(param, _propertyInfo);
BinaryExpression predicateExpr = Expression.Equal(propertyExpr, Expression.Constant(identifierObj, _propertyInfo.PropertyType));
return(Expression.Lambda <Func <TItem, bool> >(predicateExpr, param));
}
public Expression <Func <TItem, bool> > GetPredicate(string identifier)
{
try
{
TReturn convertedIdentifier = ConversionUtility.ConvertString <TReturn>(identifier);
return(_predicateGetter(convertedIdentifier));
}
catch (Exception ex) when(ex is FormatException || ex is InvalidCastException)
{
// TODO hiding exception.. includes FormatException thrown in ConversionUtility
return(null);
}
}
public Expression GetFilterExpression(ParameterExpression itemPram, FilterComparisonOperator comparisonOperator, string valueString)
{
var getterMemberExpr = _reader.GetSelectExpression(itemPram);
if (getterMemberExpr == null)
{
throw new InvalidCastException("Getter expression returned from IFieldReader is not of type MemberExpression.");
}
object valueObj = ConversionUtility.ConvertString(valueString, _reader.FieldType);
ConstantExpression variableExpression = Expression.Constant(valueObj, _reader.FieldType); // TODO variable not constant?
var operatorMethod = GetOperatorExpressionMethod(comparisonOperator);
Expression predicateExpression = operatorMethod.Invoke(getterMemberExpr, variableExpression);
return(predicateExpression);
}
public TItem GetAlreadyLoadedItem(string identifier)
{
var parameters = _getterMethod.GetParameters();
Debug.Assert(parameters.Length == 1, "Should be exactly 1 parameter by the time we get here.");
Type paramType = parameters[0].ParameterType;
object arg = ConversionUtility.ConvertString(identifier, paramType);
object methodValue = _getterMethod.Invoke(_instance, new object[] { arg });
if (methodValue is TItem)
{
return((TItem)methodValue);
}
throw new IdentifierMethodNullException();
}
public void SetValue(TItem item, string identifier)
{
var newReference = ConversionUtility.ConvertString(identifier, _propertyInfo.PropertyType);
_propertyInfo.SetValue(item, newReference);
}