Okay having read your comment, you should use a formulation that allows you not to repeat things.
What you're actually trying to do is
return mapper.ResultByRowcountForGroupSearch(searchFacilitator_.SetId,
x,
dac);
... where x is set based on the group type.
So I recommend you set up a Dictionary<int, string> (your group types are int I think?), and populate it either statically or in the constructor of the enclosing class (probably statically if the mappings are something you can write in at compile time), e.g.:
static Dictionary<int, string> groupTypeMap = new Dictionary<int, string>();
static ClassName(){
groupTypeMap[BRGroupTypeIds.Audit] = GroupSearchBatchStrings.AUDIT_TEMPSPACE_NAME;
}
Then in the method that you're asking about, you can do
return mapper.ResultByRowcountForGroupSearch(searchFacilitator_.SetId,
groupTypeMap[searchFacilitator_.GroupType,
dac);
... or, if it's possible to not be in a group and you don't want an exception from the lookup (i.e. the actual equivalent of your switch statement):
string typeName;
return groupTypeMap.TryGetValue(searchFacilitator_.GroupType, out typeName) ?
mapper.ResultByRowcountForGroupSearch(searchFacilitator_.SetId, typename, dac) :
0;