void Main()
{
    string[] str1 = new string[] { "负", "零", "正" };
  var  result= from x in str1
                     from y in str1
                     from z in str1
                     select new {x,y,z};
    Console.WriteLine(result);
}

------解决方案--------------------

C# code

var result = (
    from x in str1
    from y in str1
    from z in str1
    select new { Value = x + y + z }
).ToList();
datagridview.DataSource = result;