private static string BuildFilterExpr(string keyName, KeyRange keyRange)
{
if (keyRange.IsSingleValue())
{
return(TableQuery.GenerateFilterCondition(keyName, QueryComparisons.Equal, keyRange.SingleValue()));
}
var expr = "";
if (keyRange.Lower.HasValue)
{
var op = keyRange.Lower.Value.IsInclusive
? QueryComparisons.GreaterThanOrEqual
: QueryComparisons.GreaterThan;
expr = TableQuery.GenerateFilterCondition(keyName, op, keyRange.Lower.Value.Value);
}
if (keyRange.Upper.HasValue)
{
var op = keyRange.Upper.Value.IsInclusive
? QueryComparisons.LessThanOrEqual
: QueryComparisons.LessThan;
var ltExpr = TableQuery.GenerateFilterCondition(keyName, op, keyRange.Upper.Value.Value);
expr = string.IsNullOrEmpty(expr) ? ltExpr : TableQuery.CombineFilters(expr, TableOperators.And, ltExpr);
}
return(expr);
}
private static Func <GenericTableEntity, bool> FilterByKeyRange(Func <GenericTableEntity, string> getKey, KeyRange keyRange)
{
if (keyRange.IsSingleValue())
{
return(e => getKey(e) == keyRange.SingleValue());
}
Func <GenericTableEntity, bool> lowerFilter = e => true;
if (keyRange.Lower.HasValue)
{
var bound = keyRange.Lower.Value;
lowerFilter = e => bound.IsInclusive ? Compare(getKey(e), bound) >= 0 : Compare(getKey(e), bound) > 0;
}
Func <GenericTableEntity, bool> upperFilter = e => true;
if (keyRange.Upper.HasValue)
{
var bound = keyRange.Upper.Value;
upperFilter = e => bound.IsInclusive ? Compare(getKey(e), bound) <= 0 : Compare(getKey(e), bound) < 0;
}
return(e => lowerFilter(e) && upperFilter(e));
}