解决办法
string userIds = "1,2,3,4";
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandText = string.Format("select * from Users(nolock) where UserID in({0})", userIds);
comm.ExecuteNonQuery();
}
sql in(1,2,3)参数化查询，错误在将 varchar 值 '1,2,3,4' 转换成数据类型 int 时失败
原文：http://www.cnblogs.com/lb12081116/p/4435269.html