linq 查询

linq 分组查询：var qs = CC_.GroupBy(x => new { x.customer_name,x.sales_account,x.customer_code }).Where(Items=>Items.Key.sales_account==sales);

linq 拼接：

var q = from n in CC_
select n;
if (keys=="none"&& keys1=="")
{
q = q.Where(p => p.sales_account==sales);
}
if (keys!="none"&& keys1=="")
{
q = q.Where(p => p.sales_account == sales && p.customer_code == keys);
}
q = q.Where(p => p.storefront == st);

dataset 转 linq

dataset ds1 =new dataset()

 var q=from n in ds1.Tables[0].AsEnumerable() select n;

 

//var qs = CC_.GroupBy(x => new { x.customer_name, x.sales_account, x.customer_code }).Where(Items => Items.Key.sales_account == sales.ToLower())
var q = from n in set.Tables[0].AsEnumerable() group n by new {code=n["customer_code"],name=n["customer_name"]};