This C# function returns a randomly generated password of the specified length. You can easily modify it to include only the characters you are interested in.

1.  private string GenerateRandomPassword(int Length)
2.  {
3.      // We want all popular characters except for the ones that can easily be confused (e.g., l and 1)
4.      string[] Characters = new string[56];
5.      Characters[0] = "a";
6.      Characters[1] = "b";
7.      Characters[2] = "c";
8.      Characters[3] = "d";
9.      Characters[4] = "e";
10.     Characters[5] = "f";
11.     Characters[6] = "g";
12.     Characters[7] = "h";
13.     Characters[8] = "j";
14.     Characters[9] = "k";
15.     Characters[10] = "m";
16.     Characters[11] = "n";
17.     Characters[12] = "p";
18.     Characters[13] = "q";
19.     Characters[14] = "r";
20.     Characters[15] = "s";
21.     Characters[16] = "t";
22.     Characters[17] = "u";
23.     Characters[18] = "v";
24.     Characters[19] = "w";
25.     Characters[20] = "x";
26.     Characters[21] = "y";
27.     Characters[22] = "z";
28.     Characters[23] = "A";
29.     Characters[24] = "B";
30.     Characters[25] = "C";
31.     Characters[26] = "D";
32.     Characters[27] = "E";
33.     Characters[28] = "F";
34.     Characters[29] = "G";
35.     Characters[30] = "H";
36.     Characters[31] = "J";
37.     Characters[32] = "K";
38.     Characters[33] = "L";
39.     Characters[34] = "M";
40.     Characters[35] = "N";
41.     Characters[36] = "P";
42.     Characters[37] = "Q";
43.     Characters[38] = "R";
44.     Characters[39] = "S";
45.     Characters[40] = "T";
46.     Characters[41] = "U";
47.     Characters[42] = "V";
48.     Characters[43] = "W";
49.     Characters[44] = "X";
50.     Characters[45] = "Y";
51.     Characters[46] = "Z";
52.     Characters[47] = "2";
53.     Characters[48] = "3";
54.     Characters[49] = "4";
55.     Characters[50] = "5";
56.     Characters[51] = "6";
57.     Characters[52] = "7";
58.     Characters[53] = "8";
59.     Characters[54] = "9";
60.  
61.     Random RandChar = new Random();
62.     string Password = "";
63.  
64.     for (int i = 0; i < Length; i++)
65.     {
66.         Password += Characters[RandChar.Next(0, 55)];
67.     }
68.  
69.     return Password;
70. }
71.  
72. // How to use it
73. // MessageBox.Show(GenerateRandomPassword(6));