linq query for update more than one record

I have a table named industries. In this my fields are


workfor_id,workfor_usr_id,workfor_industry_id


With the same values of workfor_id, I have different workfor_industry_id's.

foreach (var k in us){ 
    var ind = dbContext.industries.Where(i => i.workfor_id == 
        k.id).Select(i => i).FirstOrDefault(); 
    string ind2 = k.industry; 
    var industryParts =   ind2.Split(','); 
    var o = (industryParts.Length); 
    for (c = 0; c < o; c++){  
    ind.workfor_id = Convert.ToInt16(k.id); 
    ind.workfor_industry_id = Convert.ToInt16(k.industryid); }
     }

To update workfor_industry_id field I have implemented inner loop inside the foreach loop to get the values of workfor_industry_id's.here same record is over loading with different workfor_industry_id's.

can you tell me how to implement this.