WinApp C# ขอความช่วยเหลือเรื่อง RegularExpressions หน่อยครับ

string[] num = new string[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",".","-" };
string rgxNumName = "0{3}|1{3}|2{3}|3{3}|4{3}|5{3}|6{3}|7{3}|8{3}|9{3}";

Regex rgx = new Regex(rgxNumName, System.Text.RegularExpressions.RegexOptions.Singleline | System.Text.RegularExpressions.RegexOptions.CultureInvariant);
MessageBox.Show((rgx.IsMatch("21221352412") ? "is" : "is not" )+ Environment.NewLine+ rgxNumName);

string[] num = new string[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",".","-" };
string rgxNumName = "0{3}|1{3}|2{3}|3{3}|4{3}|5{3}|6{3}|7{3}|8{3}|9{3}|(.){3}|(-){3}";

Regex rgx = new Regex(rgxNumName, System.Text.RegularExpressions.RegexOptions.Singleline | System.Text.RegularExpressions.RegexOptions.CultureInvariant);
MessageBox.Show((rgx.IsMatch("21221352412") ? "is" : "is not" )+ Environment.NewLine+ rgxNumName);