private static IMtQueryable <T> CriteriaToMtQuery(
List <FilterConditionDTO> conditions, IMtQueryable <T> queryable)
{
var predicateBuilder = new FilterConditionPredicateBuilder <T>(conditions);
queryable = queryable.Where(predicateBuilder.ToPredicate());
return(queryable);
}
// Currently we support only string of MtWhere. All Expressions from MtWhere are combined using 'and' into one expression.
private static Expression <Func <T, bool> > BuildExpression(IMtQueryable <T> queryable)
{
IMtQueryable <T> root = queryable;
var condtions = new List <Expression <Func <T, bool> > >();
while (root.Previous != null)
{
if (root is MtQueryAll <T> )
{
break;
}
if (root is MtWhere <T> )
{
condtions.Add(((MtWhere <T>)root).Condition);
}
else
{
throw new NotSupportedException(string.Format("Query part {0} is not supported", root.GetType().Name));
}
root = root.Previous;
}
Expression <Func <T, bool> > result;
if (condtions.Count == 0)
{
result = x => true;
}
else if (condtions.Count == 1)
{
result = condtions[0];
}
else
{
var sourceParameter = condtions[0].Parameters[0];
var temp = ReplaceParameter(condtions[condtions.Count - 1], sourceParameter);
for (int i = condtions.Count - 2; i >= 0; i--)
{
temp = Expression.AndAlso(temp, ReplaceParameter(condtions[i], sourceParameter));
}
result = Expression.Lambda <Func <T, bool> >(temp, sourceParameter);
}
return(result);
}
protected MtQueryable(IMtQueryable <T> previous, IMtQueryExecutor <T> executor)
{
Previous = previous;
Executor = executor;
}
protected MtQueryable(IMtQueryable <T> prev)
{
Previous = prev;
Executor = prev.Executor;
}
public static IMtQueryable <T> Where <T>(this IMtQueryable <T> that, Expression <Func <T, bool> > condition)
where T : Manifest
{
return(new MtWhere <T>(that, condition));
}
public static int MtCount <T>(this IMtQueryable <T> that, Expression <Func <T, bool> > condition)
where T : Manifest
{
var where = new MtWhere <T>(that, condition);
return(where.Executor.Count(where));
}
public static int MtCount <T>(this IMtQueryable <T> that)
where T : Manifest
{
return(that.Executor.Count(that));
}
public MtWhere(IMtQueryable <T> prev, Expression <Func <T, bool> > condition)
: base(prev)
{
Condition = condition;
}
public int Count(IMtQueryable <T> queryable)
{
var result = BuildExpression(queryable);
return(_mtObjectRepository.Count(_currentAccountId, result));
}
public IEnumerator <T> RunQuery(IMtQueryable <T> queryable)
{
var result = BuildExpression(queryable);
return(_mtObjectRepository.Query(_currentAccountId, result).GetEnumerator());
}
