Dim a As Boolean
Private Sub Command1_Click()
If a Then
    Label1.Caption = "Click to change"
    a = False
Else
    Label1.Caption = "Text changed!"
    a = True
End If
End Sub

Private Sub Form_Load()
a = False
Label1.Caption = "Click button to change text"
End Sub
 

label.caption = "text to display"
 

Public Class Form1
    Const check As Integer = 1
    Const ack As Integer = 2
    Const danger As Integer = 3
    Const tout As Integer = 4
    Const incr As Integer = 5
    Const reset1 As Integer = 6
    Const endack As Integer = 7
    Const sendadd As Integer = 8
    Const taskcomp As Integer = 9
    Const ready As Integer = 10
    Const invalid As Integer = 11
    Dim rst As Integer
    Dim i As Integer
    Dim data1 As String
    Dim status(255) As Integer
    Dim dng_address As String
    Dim instr As Integer
    Dim toutaddr As Integer
    Dim endacko As Integer
    Dim readyinp As Integer
    Dim temp As Integer
    Private Sub MONITOR_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MONITOR.Click
        Label2.Text = "SYSTEM IS MONITORING"
        AxMSComm1.InBufferCount() = 0 'CLEAR THE BUFFERS
        AxMSComm1.OutBufferCount() = 0
        AxMSComm1.Settings = "9600,n,8,1" ' SEND SETTINGS TO PORT
        AxMSComm1.PortOpen = True ' MAKE THE PORT OPEN
back: AxMSComm1.Output = ready & Chr(13) 'SEND READY COMMAND TO MICROCONTROLLER
        While (AxMSComm1.InBufferCount = 0) 'WAIT FOR READY COMMAND FROM MICROCONTROLLER
        End While
        Dim temp2 As String
        temp2 = AxMSComm1.Input 'ASSIGN TEMP2 AS INPUT RECEIVED FROM MIC
        ' if there is input from 8051
        PictureBox5.Image = System.Drawing.Image.FromFile("c:\4.jpg") 'DISPLAY IMAGE OF NOKIA CONNECTION ESTABLISHED
        Label4.Text = "CONNECTION ESTABLISHED"
        Label2.Enabled = False
        GoTo checkinput ' JUMP TO CHECKINPUT IF RECEIVED FROM MIC

checkinput:
        Label2.Text = "SYSTEM IS CHECKING THE INPUT"
        If (rst = 1) Then 'IF RESET BUTTON IS PRESSED CALL RESET SUBROUTINE
            Call reset()
        Else
            AxMSComm1.InBufferCount() = 0
            AxMSComm1.Output = check & Chr(13) 'SEND CHECK COMMAND TO MIC
            While (AxMSComm1.InBufferCount = 0) 'WAIT TILL MIC REPLIES
            End While
            data1 = AxMSComm1.Input
            Select Case data1 ' COMPARE THE DATA ONE RECEIVED WITH ALL POSSIBLE PARAMETERS
                Case endack
                    GoTo endacknowledge
                Case danger
                    GoTo danger_tree
                Case tout
                    GoTo tout_tree
            End Select
        End If
        Label2.Enabled = False

endacknowledge: Label2.Text = "END ACKNOWLEDGE SIGNAL RECEIVED"
        GoTo checkinput 'AGAIN CHECK FOR THE INPUT FROM MIC

danger_tree: Label2.Text = "SOME DANGER OCCURED"
        PictureBox6.Image = System.Drawing.Image.FromFile("c:\3.jpg") 'DISPLAY DANGER IMAGE IN PIC BOX 6 IF DANGER COMMAND IS RECEIVED
        My.Computer.Audio.Play("C:\fire alarm.wav", AudioPlayMode.WaitToComplete) 'PLAY DANGER SIREN
        AxMSComm1.InBufferCount() = 0
        AxMSComm1.OutBufferCount() = 0
        AxMSComm1.Output = sendadd & Chr(13) 'SEND ADDRESS command TO MIC
        While (AxMSComm1.InBufferCount = 0) ' WAIT FOR THE ADDRESS TO COME IN BUFFER
        End While
        dng_address = AxMSComm1.Input 'ASSIGN ADDRESS TO DNG_ADDRESS
        Select Case dng_address 'COMPARE THE ADRESS RECEIVED WITH 1,2,3,4...... AND SHOW DANGER IN CORRESPONG PICBOX
            Case 1
                PictureBox1.Image = System.Drawing.Image.FromFile("c:\1.jpg")
                status(1) = 1 'IF DANGER IS IN TREE 1 MARK THE ARRAY LOCATION 1 AS AFFECTED
            Case 2
                PictureBox2.Image = System.Drawing.Image.FromFile("c:\1.jpg")
                status(2) = 1
            Case 3
                PictureBox3.Image = System.Drawing.Image.FromFile("c:\1.jpg")
                status(3) = 1
            Case 4
                PictureBox4.Image = System.Drawing.Image.FromFile("c:\1.jpg")
                status(4) = 1
            Case 5
                PictureBox5.Image = System.Drawing.Image.FromFile("c:\1.jpg")
                status(5) = 1
        End Select
        For Me.i = 1 To 5
            If status(i) = 1 Then
                AxMSComm1.Output = incr & Chr(13) 'IF DANGER OCCURS IN ANY CASE THAN SEND INCREMENT COMMAND TO MIC
                temp = i
            Else
            End If
        Next
        While (AxMSComm1.InBufferCount = 0) 'WAIT UNTIL SENDADDRESS COMMAND COMES FROM MIC
        End While
        Dim temp3 As String
        temp3 = AxMSComm1.Input
        AxMSComm1.Output = (temp - 1) & Chr(13) 'VB SENDS ADDR-1 TO MIC TO INCR
        AxMSComm1.OutBufferCount() = 0
        While (AxMSComm1.InBufferCount = 0) ' WAIT TILL TASK COMPLETE COMMAND IS RECEIVED
        End While
        Dim temp4 As String
        temp4 = AxMSComm1.Input
        AxMSComm1.InBufferCount() = 0
        Label2.Enabled = False
        GoTo checkinput 'AGAIN CHECK FOR INPUT
tout_tree: Label2.Text = "TIMEOUT OCCURED" ' TIMEOUT IS THE CASE WHEN THERE IS PROBLEM IN BATTERY ETC
        My.Computer.Audio.Play("C:\fire alarm.wav", AudioPlayMode.WaitToComplete) 'PLAY DANGER SIREN
        AxMSComm1.Output = sendadd & Chr(13) 'VB WANTS ADDRESS OF TIMEOUT LOCATION
        While (AxMSComm1.InBufferCount = 0) 'WAIT TILL ADDRESS OF TIMEOUT LOCATION IS RECEIVED
        End While
        toutaddr = AxMSComm1.Input
        PictureBox6.Image = System.Drawing.Image.FromFile("c:\3.jpg")
        Select Case toutaddr 'COMPARE THE ADRESS RECEIVED WITH 1,2,3,4...... AND SHOW TIMEOUT IN CORRESPONG PICBOX
            Case 1
                PictureBox1.Image = System.Drawing.Image.FromFile("c:\5.jpg")
                status(1) = 2
            Case 2
                PictureBox2.Image = System.Drawing.Image.FromFile("c:\5.jpg")
                status(2) = 2
            Case 3
                PictureBox3.Image = System.Drawing.Image.FromFile("c:\5.jpg")
                status(3) = 2
            Case 4
                PictureBox4.Image = System.Drawing.Image.FromFile("c:\5.jpg")
                status(4) = 2
            Case 5
                PictureBox5.Image = System.Drawing.Image.FromFile("c:\5.jpg")
                status(5) = 2
        End Select
        For Me.i = 1 To 5
            If status(i) = 2 Then
                AxMSComm1.Output = incr & Chr(13) 'SEND INCREMENT COMMAND TO MIC
                AxMSComm1.OutBufferCount() = 0
                temp = i
            Else
            End If
        Next
        While (AxMSComm1.InBufferCount = 0) 'Mic WANTS ADDR OF WHICH LOCATION TO INCREMENT
        End While
        Dim temp5 As String
        temp5 = AxMSComm1.Input
        AxMSComm1.Output = (temp - 1) & Chr(13) 'VB SENDS ADDR-1 TO MIC
        AxMSComm1.OutBufferCount() = 0
        While (AxMSComm1.InBufferCount = 0) 'WAIT TILL TASK COMPLETE CODE IS RECEIVED
        End While
        Dim temp6 As String
        temp6 = AxMSComm1.Input
        Label2.Enabled = False
        GoTo checkinput
    End Sub
    Private Sub RESET2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RESET2.Click
        rst = 1
    End Sub

    Function reset() As Single
        Dim TEMP_RESET As Integer
        Label2.Text = "RESETTING THE NETWORK PLZ WAIT"
        rst = 0
        For Me.i = 1 To 5
            If status(i) = 1 Or status(i) = 2 Then 'IF TIMEOUT OR DANGER HAS OCCURED
                AxMSComm1.Output = reset1 'SENDS RST COMMAND TO MIC
                AxMSComm1.OutBufferCount() = 0
                TEMP_RESET = i
                status(i) = 0
            End If
        Next
        While (AxMSComm1.InBufferCount = 0) 'Mic WANTS ADDR OF WHICH LOCATION TO RESET
        End While
        Dim粑TEMP4 As Integer
        TEMP4 = AxMSComm1.Input
        AxMSComm1.Output = TEMP_RESET - 1 'VB SENDS ADDR-1 TO MIC
        While (AxMSComm1.InBufferCount = 0) 'WAIT TILL TASC COMPLETE CODE IS RECEIVED BY VB
        End While
        Dim TEMP5 As Integer
        TEMP5 = AxMSComm1.Input


        PictureBox1.Image = System.Drawing.Image.FromFile("c:\2.jpg") ' CHANGE THE PICTURES AS DEFAULT
        PictureBox2.Image = System.Drawing.Image.FromFile("c:\2.jpg")
        PictureBox3.Image = System.Drawing.Image.FromFile("c:\2.jpg")
        PictureBox4.Image = System.Drawing.Image.FromFile("c:\2.jpg")
        PictureBox5.Image = System.Drawing.Image.FromFile("c:\2.jpg")
        Label2.Enabled = False
    End Function

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Label3.Text = TimeString
    End Sub
End Class