Csharp C# 正则表达式不匹配字符串

无法为C#中的字符串构建正确的正则表达式

我有一个看起来像这样的字符串:

 string str1 = "f1/9999/d1/310822/orig1/GYD/dest1/SAW/f2/7777/d2/300922/orig2/SAW/dest2/GYD";

我正在try 构建一个正则表达式，该表达式将与上面的字符串匹配，但满足以下条件:

(我会将上面的字符串拆分成子字符串，以便更好地解释我需要的内容)

f1- is text that never changing "9999" should always be a digits and length of this substring may vary from 2-6 characters
"d1"- this text that never changing "310822" - should always be a digits and length of this substring may vary from 2-6 characters
"orig1" - is text that never changing
"GYD" -should be always be a A-Z characters, length always 3 dest1- this text never changing
"SAW" -should be always be a A-Z characters, length always 3
"f2" -this text that never changing
"7777" - should always be a digits and length of this substring may vary from 2-6 characters
"d2" - this text never changing
"300922" -should always be a digits and length of this substring may vary from 2-6 characters
"orig2" - this text never changing
"SAW" - should be always be a A-Z characters, length always 3
"dest2"-this text never changing
"GYD" -should be always be a A-Z characters, length always 3

另外，所有的斜杠都应该放在正确的位置.

我曾try 构建如下所示的正则表达式，但不起作用:

 string str1 = "f1/123456/d1/310822/orig1/GYD/dest1/SAW/f2/7777/d2/300922/orig2/SAW/dest2/GYD";

        if (Regex.IsMatch(str1, @"^[f1][/]\d{2,6}[/][d1][/]\d{2,6}[/][orig1][/]\b[a-zA-Z]{3}\b[/][dest1][/]\b[a-zA-Z]{3}\b[/][f2][/]\d{2,6}[/][d2][/]\d{2,6}[/][orig2][/]\b[a-zA-Z]{3}\b[/][dest2][/]\b[a-zA-Z]{3}\b$"))
        {
            richTextBox1.Text = "true";
        }
        else { richTextBox1.Text = "false"; }

我总是得到"假的". 您知道如何为字符串str1构建正确的正则表达式吗？​