How to Create a Ninja Defuse [Minigame] in Visual Basic

Introduction: Welcome to a tutorial on a small game to be made in Visual Basic - Ninja Defuse. A game to guess a randomly generated three digit code before the time runs out. Steps of Creation: Step 1: First we need to create our form with... - Textbox1 - First digit of guessed code - Textbox2 - Second - Textbox3 - Third - Label1 - Information of time - Label2 - Time remaining - Button1 - Begin game/countdown Ensure that the maximum character limit for all the textboxes are 1. Step 2: Lets create our variables and threads which we will be using... Our function will also be used later which will ensure any text entered in to our three, single digit textboxes are digits instead of symbols or letters. Step 3: Now we want to ensure that any text entered in to our digit boxes are numbers (using our custom functions)... Step 4: In order to use our custom threads to interact with the time label we want to make illegalcrossthreadcalls unchecked, so on form1 add this: Step 5: For the begin button we want to generate our randomised key, ensure our textboxes are enabled and initiate our threads...

1. Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
2.     If (Not ran) Then
3.         ran = True
4.         Dim rand As Random = New Random
5.         key = ""
6.         For i As Integer = 0 To 2
7.             Dim r As Integer = rand.Next(9)
8.             key &= r
9.             r = Nothing
10.         Next
11.         'MsgBox(key)' Uncomment to see the key for testing.
12.         TextBox1.Enabled = True
13.         TextBox2.Enabled = True
14.         TextBox3.Enabled = True
15.         trd.IsBackground = True
16.         trd.Start()
17.         trd2.IsBackground = True
18.         trd2.Start()
19.     End If
20. End Sub

Step 6: Finally lets add our two more custom functions courtesy of our threads which will; Countdown the time remaining, and check the entered key...

1. Private Function checkKey()
2.     Do Until seconds = 0
3.         Dim s As String = TextBox1.Text & TextBox2.Text & TextBox3.Text
4.         If (s = key) Then
5.             MsgBox("You found the key! You Ninja.")
6.             If (trd.IsAlive) Then trd.Suspend()
7.             If (trd2.IsAlive) Then trd2.Suspend()
8.             TextBox1.Enabled = False
9.             TextBox2.Enabled = False
10.             TextBox3.Enabled = False
11.             seconds = 0
12.         End If
13.     Loop
14.     seconds = 60
15. End Function
16.  
17. Private Function timeDown()
18.     Do Until seconds = 0
19.         seconds -= 1
20.         Label2.Text = seconds
21.         Threading.Thread.Sleep(1000)
22.     Loop
23.     TextBox1.Enabled = False
24.     TextBox2.Enabled = False
25.     TextBox3.Enabled = False
26. End Function

Project Complete! Thank you for reading my tutorial. Below is the full source code and download for the project files.

1. Public Class Form1
2. Dim trd As Threading.Thread = New Threading.Thread(AddressOf timeDown)
3. Dim trd2 As Threading.Thread = New Threading.Thread(AddressOf checkKey)
4. Dim key As String = "111"
5. Dim seconds As Integer = 60
6. Dim ran As Boolean = False
7. Private Function isNumber(ByVal s As String)
8.     If (s = "0" Or s = "1" Or s = "2" Or s = "3" Or s = "4" Or s = "5" Or s = "6" Or s = "7" Or s = "8" Or s = "9") Then
9.         Return True
10.     End If
11.     Return False
12. End Function
13. Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
14.     If Not (isNumber(sender.ToString().Chars(sender.ToString().Length - 1))) Then
15.         TextBox1.Text = ""
16.     End If
17. End Sub
18.  
19. Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged
20.     If Not (isNumber(sender.ToString().Chars(sender.ToString().Length - 1))) Then
21.         TextBox2.Text = ""
22.       End If
23. End Sub
24.  
25. Private Sub TextBox3_TextChanged(sender As Object, e As EventArgs) Handles TextBox3.TextChanged
26.     If Not (isNumber(sender.ToString().Chars(sender.ToString().Length - 1))) Then
27.         TextBox3.Text = ""
28.     End If
29. End Sub
30.  
31.     Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
32.         CheckForIllegalCrossThreadCalls = False
33.         TextBox1.Enabled = False
34.         TextBox2.Enabled = False
35.         TextBox3.Enabled = False
36.     End Sub
37.  
38. Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
39.     If (Not ran) Then
40.         ran = True
41.         Dim rand As Random = New Random
42.         key = ""
43.         For i As Integer = 0 To 2
44.             Dim r As Integer = rand.Next(9)
45.             key &= r
46.             r = Nothing
47.         Next
48.         'MsgBox(key)' Uncomment to see the key for testing.
49.         TextBox1.Enabled = True
50.         TextBox2.Enabled = True
51.         TextBox3.Enabled = True
52.         trd.IsBackground = True
53.         trd.Start()
54.         trd2.IsBackground = True
55.         trd2.Start()
56.     End If
57. End Sub
58.  
59. Private Function checkKey()
60.     Do Until seconds = 0
61.         Dim s As String = TextBox1.Text & TextBox2.Text & TextBox3.Text
62.         If (s = key) Then
63.             MsgBox("You found the key! You Ninja.")
64.             If (trd.IsAlive) Then trd.Suspend()
65.             If (trd2.IsAlive) Then trd2.Suspend()
66.             TextBox1.Enabled = False
67.             TextBox2.Enabled = False
68.             TextBox3.Enabled = False
69.             seconds = 0
70.         End If
71.     Loop
72.     seconds = 60
73. End Function
74.  
75. Private Function timeDown()
76.     Do Until seconds = 0
77.         seconds -= 1
78.         Label2.Text = seconds
79.         Threading.Thread.Sleep(1000)
80.     Loop
81.     TextBox1.Enabled = False
82.     TextBox2.Enabled = False
83.     TextBox3.Enabled = False
84. End Function
85. End Class