private IQueryable <TEntity> FilterExpression <TEntity>(IQueryable <TEntity> query, IFilterDescriptor filter)
where TEntity : class
{
try {
Expression <Func <TEntity, bool> > filterExpression = null;
if (filter is CompositeFilterDescriptor)
{
foreach (IFilterDescriptor childFilter in ((CompositeFilterDescriptor)filter).FilterDescriptors)
{
query = FilterExpression <TEntity>(query, childFilter);
}
}
else
{
FilterDescriptor filterDescriptor = (FilterDescriptor)filter;
ParameterExpression paramExp = Expression.Parameter(typeof(TEntity));
Expression exp = filterDescriptor.CreateFilterExpression(paramExp);
//MemberExpression fieldExp = Expression.PropertyOrField(paramExp, filterDescriptor.Member);
//ConstantExpression valueExp = Expression.Constant(filterDescriptor.Value, filterDescriptor.Value.GetType());
//Expression exp = null;
//if (fieldExp.Type == typeof(string))
//{
// MethodInfo method = typeof(string).GetMethod(filterDescriptor.Operator.ToString(), new[] { typeof(string) });
// exp = Expression.Call(fieldExp, method, valueExp);
//}
//else if (filterDescriptor.MemberType == typeof(int)
// || filterDescriptor.MemberType == typeof(long))
//{
// exp = Expression.LessThanOrEqual(fieldExp, valueExp);
//}
//else
//{
// exp = Expression.Equal(fieldExp, valueExp);
//}
filterExpression = Expression.Lambda <Func <TEntity, bool> >(exp, paramExp);
query = query.Where(filterExpression);
}
return(query);
}
catch (Exception ex) {
bool rethrow;
rethrow = DataExceptionHandler.HandleException(ref ex);
if (rethrow)
{
throw ex;
}
return(null);
}
}