[VB 2008] Calculator and count down timer sources

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[VB 2008] Calculator and count down timer sources
  1. Unread #1 - Apr 13, 2008 at 6:14 AM
  2. Flaming Idiots
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    Visual Basic Programmers

    [VB 2008] Calculator and count down timer sources
    First is the calculator source. While it is really big, it shouldn't be too hard to use.

    Here is an example of how to use it:
    Code:
    Dim Exp As New MathExpressionParser()
Dim Result = Exp.ParseExpression("4+5^2-sin(8)").Invoke
    Here is the code for the calculator. I suggest you put it in its own file.
    Code:
    Public NotInheritable Class MathExpressionParser

    Sub New()

        With VariableTable
            .Add("pi", Math.PI)
            .Add("e", Math.E)
            .Add("x", Function() Me.X)
        End With

        With FunctionTable
            .Add("sum", AddressOf Functions.Sum)
            .Add("average", AddressOf Functions.Average)
            .Add("min", AddressOf Functions.Min)
            .Add("max", AddressOf Functions.Max)
            .Add("floor", AddressOf Math.Floor)
            .Add("ceil", AddressOf Math.Ceiling)
            .Add("sin", AddressOf Math.Sin)
            .Add("cos", AddressOf Math.Cos)
            .Add("tan", AddressOf Math.Tan)
            .Add("sinh", AddressOf Math.Sinh)
            .Add("cosh", AddressOf Math.Cosh)
            .Add("tanh", AddressOf Math.Tanh)
            .Add("abs", AddressOf Math.Abs)
            .Add("round", AddressOf Math.Round)
            .Add("~", AddressOf Math.Round)
            .Add("sqrt", AddressOf Math.Sqrt)
            .Add("if", Function(Val As Decimal, [True] As Decimal, [False] As Decimal) If(Val <> 0, [True], [False]))
            .Add("?", Function(Val As Decimal, [True] As Decimal, [False] As Decimal) If(Val <> 0, [True], [False]))
            .Add("add", Function(Left As Decimal, Right As Decimal) Left + Right)
            .Add("sub", Function(Left As Decimal, Right As Decimal) Left - Right)
            .Add("mul", Function(Left As Decimal, Right As Decimal) Left * Right)
            .Add("div", Function(Left As Decimal, Right As Decimal) Left / Right)
            .Add("mod", Function(Left As Decimal, Right As Decimal) Left Mod Right)
            .Add("pow", Function(Left As Decimal, Right As Decimal) Left ^ Right)
            .Add("root", Function(Left As Decimal, Right As Decimal) Left ^ If(Right = 0, 0, (1 / Right)))
        End With

        With OperatorTable
            .Add("+", AddressOf DecimalExpression.Add, OperatorTable.OperatorLevel.Additive)
            .Add("-", AddressOf DecimalExpression.Subtract, OperatorTable.OperatorLevel.Additive)
            .Add("*", AddressOf DecimalExpression.Multiply, OperatorTable.OperatorLevel.Multiplicative)
            .Add("/", AddressOf DecimalExpression.Divide, OperatorTable.OperatorLevel.Multiplicative)
            .Add("%", AddressOf DecimalExpression.Modulo, OperatorTable.OperatorLevel.Multiplicative)
            .Add("^", AddressOf DecimalExpression.Power, OperatorTable.OperatorLevel.Exponential)
            .Add("<", AddressOf DecimalExpression.LessThan, OperatorTable.OperatorLevel.Comparitive)
            .Add(">", AddressOf DecimalExpression.GreaterThan, OperatorTable.OperatorLevel.Comparitive)
            .Add("=", AddressOf DecimalExpression.Equals, OperatorTable.OperatorLevel.Comparitive)
            .Add("!", AddressOf DecimalExpression.NotEqual, OperatorTable.OperatorLevel.Comparitive)
            .Add("|", AddressOf DecimalExpression.Or, OperatorTable.OperatorLevel.Comparitive)
            .Add("&", AddressOf DecimalExpression.And, OperatorTable.OperatorLevel.Comparitive)
        End With

    End Sub

    Private Class Functions
        Public Shared Function Sum(ByVal Items As Decimal()) As Decimal
            Sum = 0
            For Each I In Items
                Sum += I
            Next
        End Function
        Public Shared Function Average(ByVal Items As Decimal()) As Decimal
            Return Sum(Items) / Items.Length
        End Function
        Public Shared Function Min(ByVal Items As Decimal()) As Decimal
            Min = Items(0)
            For Each I In Items
                Min = Math.Min(Min, I)
            Next
        End Function
        Public Shared Function Max(ByVal Items As Decimal()) As Decimal
            Max = Items(0)
            For Each I In Items
                Max = Math.Max(Max, I)
            Next
        End Function
    End Class

    Public Function ParseExpression(ByVal Expression As String) As DecimalExpression
        Return Combine(SplitExpression(Expression))
    End Function

    Private Function SplitExpression(ByVal Expression As String) As String()
        Dim L = New List(Of String)
        Dim OPs = Aggregate I In OperatorTable Select I.Symbol Into ToArray()   'New Char() {"+", "-", "*", "/", "%", "^", "<", ">", "=", "!", "&", "|"}
        Dim WasOP As Boolean = True
        Dim Current = ""
        Dim BracketLevel = 0
        For Each C In Expression.Replace(" ", "")
            If C = "("c Then BracketLevel += 1
            If C = ")"c Then BracketLevel -= 1
            If WasOP Then
                WasOP = False
                If Current.Length > 0 Then L.Add(Current.Trim)
                Current = C
            Else
                If OPs.Contains(C) AndAlso BracketLevel = 0 Then
                    If Current.Length > 0 Then L.Add(Current.Trim)
                    Current = C
                    WasOP = True
                Else
                    Current &= C
                End If
            End If
        Next
        If Current.Length > 0 Then L.Add(Current)
        Return L.ToArray
    End Function

    Private Function SplitParams(ByVal Expression As String) As String()
        Dim L = New List(Of String)
        Dim OPs = New Char() {","}
        Dim WasOP As Boolean = False
        Dim Current = ""
        Dim BracketLevel = 0
        For Each C In Expression.Replace(" ", "")
            If C = "("c Then BracketLevel += 1
            If C = ")"c Then BracketLevel -= 1
            If WasOP Then
                WasOP = False
                If Current.Length > 0 Then L.Add(Current.Trim)
                Current = C
            Else
                If OPs.Contains(C) AndAlso BracketLevel = 0 Then
                    If Current.Length > 0 Then L.Add(Current.Trim)
                    Current = C
                    WasOP = True
                Else
                    Current &= C
                End If
            End If
        Next
        If Current.Length > 0 Then L.Add(Current)
        Return L.Where(Function(c As String) c <> ",").ToArray
    End Function

    Private Function Combine(ByVal Split As String()) As DecimalExpression
        Dim Vals As New List(Of DecimalExpression)
        Dim Ops As New List(Of OperatorTable.OperatorReference)
        For Each I In Split
            If I.Length = 1 AndAlso OperatorTable.ContainsOperator(I) Then
                Ops.Add(OperatorTable(I))
            Else
                If I.StartsWith("(") Then
                    Vals.Add(Combine(SplitExpression(I.Substring(1, I.Length - 2))))
                ElseIf I.EndsWith(")") Then
                    Dim name = I.Split("(").First.ToLower
                    Dim Params = Aggregate Param In SplitParams(I.Substring(name.Length + 1, I.Length - name.Length - 2)) Select Me.ParseExpression(Param) Into ToArray()
                    Vals.Add(GetFunction(name, Params))
                Else
                    Vals.Add(ParseValue(I))
                End If
            End If
        Next
S:
        For Each G In [Enum].GetValues(GetType(OperatorTable.OperatorLevel)).Cast(Of OperatorTable.OperatorLevel)()
            For n = 0 To Ops.Count - 1
                Dim OP = Ops(n)
                If G = OP.Level Then
                    Dim Left = Vals(n), Right = Vals(n + 1)
                    Dim E = OP.Operator(Left, Right)
                    Ops.Remove(OP)
                    Vals.RemoveRange(n, 2)
                    Vals.Insert(n, E)
                    GoTo S
                End If
            Next
        Next
        Return Vals.First
    End Function

    Private Function ParseValue(ByVal E As String) As DecimalExpression
        If System.Text.RegularExpressions.Regex.IsMatch(E, "\-?[\d\.]+") Then Return Decimal.Parse(E) Else Return GetVariable(E)
    End Function

    Private _variableTable As New VariableTable
    Public ReadOnly Property VariableTable() As VariableTable
        Get
            Return _variableTable
        End Get
    End Property
    Private _functionTable As New FunctionTable
    Public ReadOnly Property FunctionTable() As FunctionTable
        Get
            Return _functionTable
        End Get
    End Property
    Private _operatorTable As New OperatorTable
    Public ReadOnly Property OperatorTable() As OperatorTable
        Get
            Return _operatorTable
        End Get
    End Property

    Private Function GetVariable(ByVal name As String) As DecimalExpression
        Dim Result As DecimalExpression = 0
        Dim Neg = name.StartsWith("-")
        If Neg Then name = name.Substring(1)
        Dim V = VariableTable.IsConstant(name)
        If V.HasValue AndAlso V.Value Then Return If(Neg, -VariableTable(name), VariableTable(name))

        Result = DecimalExpression.Func(Function() If(VariableTable.ContainsVariable(name), VariableTable(name), 0D))
        Return If(Neg, DecimalExpression.Multiply(-1, Result), Result)
    End Function

    Private Function GetFunction(ByVal name As String, ByVal ParamArray args() As DecimalExpression) As DecimalExpression
        Dim Result As DecimalExpression = 0
        Dim Neg = name.StartsWith("-")
        If Neg Then name = name.Substring(1)
        Result = DecimalExpression.Func(Function() If(FunctionTable.ContainsFunction(name.ToLower), DynInvoke(name, args), 0))
        Return If(Neg, DecimalExpression.Multiply(-1, Result), Result)
    End Function

    Private Function DynInvoke(ByVal Name As String, ByVal Args() As DecimalExpression) As Decimal
        Dim Method = FunctionTable(Name.ToLower)
        If Method.Method.GetParameters().First().ParameterType.IsArray Then
            Return Method.DynamicInvoke(Aggregate I In Args Select CDec(I.Invoke) Into ToArray())
        Else
            Return Method.DynamicInvoke(Aggregate I In Args Select CObj(I.Invoke) Into ToArray())
        End If
    End Function

    Private _x As Decimal
    Public Property X() As Decimal
        Get
            Return _x
        End Get
        Set(ByVal value As Decimal)
            _x = value
        End Set
    End Property


End Class


Public NotInheritable Class FunctionTable
    Private Items As New Dictionary(Of String, [Delegate])
    Public Sub Add(ByVal Name As String, ByVal [Function] As Func(Of Decimal, Decimal))
        Items.Add(Name.ToLower, [Function])
    End Sub
    Public Sub Add(ByVal Name As String, ByVal [Function] As Func(Of Decimal, Decimal, Decimal))
        Items.Add(Name.ToLower, [Function])
    End Sub
    Public Sub Add(ByVal Name As String, ByVal [Function] As Func(Of Decimal, Decimal, Decimal, Decimal))
        Items.Add(Name.ToLower, [Function])
    End Sub
    Public Sub Add(ByVal Name As String, ByVal [Function] As Func(Of Decimal, Decimal, Decimal, Decimal, Decimal))
        Items.Add(Name.ToLower, [Function])
    End Sub
    Public Sub Add(ByVal Name As String, ByVal [Function] As [Delegate])
        Items.Add(Name.ToLower, [Function])
    End Sub
    Public Sub Add(ByVal Name As String, ByVal [Function] As Func(Of Decimal(), Decimal))
        Items.Add(Name.ToLower, [Function])
    End Sub
    Public Function ContainsFunction(ByVal Name As String) As Boolean
        Return Items.ContainsKey(Name.ToLower)
    End Function
    Default Public ReadOnly Property [Function](ByVal Name As String) As [Delegate]
        Get
            Return If(Items.ContainsKey(Name.ToLower), Items(Name.ToLower), Nothing)
        End Get
    End Property
    Public Sub RemoveFunction(ByVal Name As String)
        If ContainsFunction(Name) Then Items.Remove(Name.ToLower)
    End Sub
End Class


Public NotInheritable Class VariableTable
    Private Items As New Dictionary(Of String, Func(Of Decimal))
    Private ConstTable As New Dictionary(Of String, Boolean)
    Public Sub Add(ByVal Name As String, ByVal Provider As Func(Of Decimal))
        Items.Add(Name.ToLower, Provider)
        ConstTable.Add(Name.ToLower, False)
    End Sub
    Public Sub Add(ByVal Name As String, ByVal Value As Decimal)
        Items.Add(Name.ToLower, Function() Value)
        ConstTable.Add(Name.ToLower, True)
    End Sub
    Public Function ContainsVariable(ByVal Name As String) As Boolean
        Return Items.ContainsKey(Name.ToLower)
    End Function
    Public Function IsConstant(ByVal Name As String) As Boolean?
        Return If(ConstTable.ContainsKey(Name.ToLower), ConstTable(Name.ToLower), Nothing)
    End Function
    Default Public ReadOnly Property Value(ByVal Name As String) As Decimal
        Get
            Return If(Items.ContainsKey(Name.ToLower), Items(Name.ToLower).Invoke, 0D)
        End Get
    End Property
    Public Sub RemoveVariable(ByVal Name As String)
        If ContainsVariable(Name) Then Items.Remove(Name.ToLower)
    End Sub
End Class

Public NotInheritable Class OperatorTable
    Implements IEnumerable(Of OperatorReference)

    Private Items As New List(Of OperatorReference)
    Public Sub Add(ByVal Symbol As Char, ByVal [Operator] As [Operator], ByVal Level As OperatorLevel)
        Items.Add(New OperatorReference(Symbol, [Operator], Level))
    End Sub
    Public Function ContainsOperator(ByVal Symbol As Char) As Boolean
        Return Items.SingleOrDefault(Function(I As OperatorReference) I.Symbol = Symbol) IsNot Nothing
    End Function
    Default Public ReadOnly Property Value(ByVal Symbol As Char) As OperatorReference
        Get
            Return Items.SingleOrDefault(Function(I As OperatorReference) I.Symbol = Symbol)
        End Get
    End Property
    Public Sub RemoveVariable(ByVal Symbol As Char)
        Dim Op = Items.SingleOrDefault(Function(I As OperatorReference) I.Symbol = Symbol)
        If Op IsNot Nothing Then Items.Remove(Op)
    End Sub

    Public Class OperatorReference
        Sub New(ByVal Symbol As Char, ByVal [Operator] As [Operator], ByVal Level As OperatorLevel)
            Me._symbol = Symbol : Me._Operator = [Operator] : Me._level = Level
        End Sub
        Private _symbol As Char
        Public ReadOnly Property Symbol() As Char
            Get
                Return _symbol
            End Get
        End Property
        Private _Operator As [Operator]
        Public ReadOnly Property [Operator]() As [Operator]
            Get
                Return _Operator
            End Get
        End Property
        Private _level As OperatorLevel
        Public ReadOnly Property Level() As OperatorLevel
            Get
                Return _level
            End Get
        End Property
    End Class
    Public Enum OperatorLevel
        Exponential
        Multiplicative
        Additive
        Comparitive
    End Enum
    Private Function GetEnumerator() As System.Collections.Generic.IEnumerator(Of OperatorReference) Implements System.Collections.Generic.IEnumerable(Of OperatorReference).GetEnumerator
        Return Me.Items.GetEnumerator
    End Function
    Private Function GetEnumerator1() As System.Collections.IEnumerator Implements System.Collections.IEnumerable.GetEnumerator
        Return Me.Items.GetEnumerator
    End Function
End Class

Public Delegate Function [Operator](ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression


Public NotInheritable Class DecimalExpression
    Private Sub New(ByVal Expression As Func(Of Decimal))
        Me.expression = Expression
        Me.IsStatic = False
    End Sub
    Private Sub New(ByVal Value As Decimal)
        Me.expression = Function() Value
        Me.IsStatic = True
    End Sub
    Private expression As Func(Of Decimal)
    Public Function Invoke() As Decimal
        Try
            Return expression.Invoke
        Catch ex As Exception
            Throw ex
        End Try
    End Function
    Public Function Invoke(ByVal DefualtValue As Decimal) As Decimal
        Try
            Return expression.Invoke
        Catch ex As Exception
            Return DefualtValue
        End Try
    End Function

    Private IsStatic As Boolean = False

    Public Shared Widening Operator CType(ByVal Value As Decimal) As DecimalExpression
        Return New DecimalExpression(Value)
    End Operator
    Public Shared Narrowing Operator CType(ByVal Value As Func(Of Decimal)) As DecimalExpression
        Return New DecimalExpression(Value)
    End Operator
    Public Shared Function Constant(ByVal Value As Decimal) As DecimalExpression
        Return New DecimalExpression(Value)
    End Function

    Public Shared Function Add(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return Left.Invoke + Right.Invoke

        If Left.IsStatic AndAlso Left.Invoke = 0 Then Return Right.Invoke
        If Right.IsStatic AndAlso Right.Invoke = 0 Then Return Left.Invoke

        Return New DecimalExpression(Function() (Left.Invoke + Right.Invoke))
    End Function
    Public Shared Function Subtract(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(Left.Invoke - Right.Invoke)
        If Left.IsStatic AndAlso Left.Invoke = 0 Then Return -Right.Invoke
        If Right.IsStatic AndAlso Right.Invoke = 0 Then Return Left.Invoke
        Return New DecimalExpression(Function() (Left.Invoke - Right.Invoke))
    End Function
    Public Shared Function Multiply(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(Left.Invoke * Right.Invoke)
        If Left.IsStatic AndAlso Left.Invoke = 0 Then Return 0
        If Right.IsStatic AndAlso Right.Invoke = 0 Then Return 0
        Return New DecimalExpression(Function() (Left.Invoke * Right.Invoke))
    End Function
    Public Shared Function Divide(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(Left.Invoke / Right.Invoke)
        If Left.IsStatic AndAlso Left.Invoke = 0 Then Return 0
        If Right.IsStatic AndAlso Right.Invoke = 0 Then Return 0
        Return New DecimalExpression(Function() (Left.Invoke / Right.Invoke))
    End Function
    Public Shared Function Power(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(Left.Invoke ^ Right.Invoke)
        If Left.IsStatic AndAlso Left.Invoke = 0 Then Return 0
        If Right.IsStatic AndAlso Right.Invoke = 0 Then Return 1
        Return New DecimalExpression(Function() (Left.Invoke ^ Right.Invoke))
    End Function
    Public Shared Function Modulo(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(Left.Invoke Mod Right.Invoke)
        If Left.IsStatic AndAlso Left.Invoke = 0 Then Return 0
        If Right.IsStatic AndAlso Right.Invoke = 0 Then Return 0
        Return New DecimalExpression(Function() (Left.Invoke Mod Right.Invoke))
    End Function
    Public Shared Shadows Function Equals(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(If(Left.Invoke = Right.Invoke, 1, 0))
        Return New DecimalExpression(Function() (If(Left.Invoke = Right.Invoke, 1, 0)))
    End Function
    Public Shared Shadows Function GreaterThan(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(If(Left.Invoke > Right.Invoke, 1, 0))
        Return New DecimalExpression(Function() (If(Left.Invoke > Right.Invoke, 1, 0)))
    End Function
    Public Shared Shadows Function LessThan(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(If(Left.Invoke < Right.Invoke, 1, 0))
        Return New DecimalExpression(Function() (If(Left.Invoke < Right.Invoke, 1, 0)))
    End Function
    Public Shared Shadows Function NotEqual(ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(If(Left.Invoke <> Right.Invoke, 1, 0))
        Return New DecimalExpression(Function() (If(Left.Invoke <> Right.Invoke, 1, 0)))
    End Function

    Public Shared Shadows Function [Or](ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(Left.Invoke Or Right.Invoke)
        Return New DecimalExpression(Function() (Left.Invoke Or Right.Invoke))
    End Function
    Public Shared Shadows Function [And](ByVal Left As DecimalExpression, ByVal Right As DecimalExpression) As DecimalExpression
        If (Left.IsStatic And Right.IsStatic) Then Return New DecimalExpression(Left.Invoke And Right.Invoke)
        If Left.IsStatic AndAlso Left.Invoke = 0 Then Return 0
        If Right.IsStatic AndAlso Right.Invoke = 0 Then Return 0
        Return New DecimalExpression(Function() (Left.Invoke And Right.Invoke))
    End Function


    Public Shared Function Func(ByVal Method As [Delegate], ByVal ParamArray Args() As DecimalExpression) As DecimalExpression
        Return New DecimalExpression(Function() CDec(Method.DynamicInvoke(Aggregate I In Args Select CObj(I.Invoke) Into ToArray())))
    End Function
    Public Shared Function Func(ByVal Method As Func(Of IEnumerable(Of Decimal), Decimal), ByVal ParamArray Args() As DecimalExpression) As DecimalExpression
        Return New DecimalExpression(Function() Method.Invoke(From I In Args Select I.Invoke))
    End Function
    Public Shared Function Func(ByVal Method As Func(Of Decimal, Decimal), ByVal Argument As DecimalExpression) As DecimalExpression
        Return New DecimalExpression(Function() Method.Invoke(Argument.Invoke))
    End Function
    Public Shared Function Func(ByVal Method As Func(Of Decimal, Decimal, Decimal), ByVal _
                                Arg1 As DecimalExpression, ByVal Arg2 As DecimalExpression) As DecimalExpression
        Return New DecimalExpression(Function() Method.Invoke(Arg1.Invoke, Arg2.Invoke))
    End Function
    Public Shared Function Func(ByVal Method As Func(Of Decimal, Decimal, Decimal, Decimal), _
                                ByVal Arg1 As DecimalExpression, ByVal Arg2 As DecimalExpression, ByVal Arg3 As DecimalExpression) As DecimalExpression
        Return New DecimalExpression(Function() Method.Invoke(Arg1.Invoke, Arg2.Invoke, Arg3.Invoke))
    End Function
    Public Shared Function Func(ByVal Method As Func(Of Decimal, Decimal, Decimal, Decimal, Decimal), _
                                ByVal Arg1 As DecimalExpression, ByVal Arg2 As DecimalExpression, ByVal Arg3 As DecimalExpression, ByVal Arg4 As DecimalExpression) As DecimalExpression
        Return New DecimalExpression(Function() Method.Invoke(Arg1.Invoke, Arg2.Invoke, Arg3.Invoke, Arg4.Invoke))
    End Function

End Class
    Now for the count down timer, it is simple to use. Add the code to your project (should be in its own file) build it, and there should be a CountDownTimer on your toolbox.

    Here is an example for using it (I set the countdowntimer's time to 00:00:05(5 seconds)):
    Code:
        Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Me.Button1.Enabled = False
        CountDownTimer1.Start()
    End Sub
    ' This is called when it finishes the countdown.
    Private Sub CountDownTimer1_OnElapsed(ByVal sender As Object, ByVal e As System.EventArgs) Handles CountDownTimer1.OnElapsed
        Me.Button1.Enabled = True
    End Sub
    ' This is called whenever it checks if the countdown is done.
    Private Sub CountDownTimer1_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles CountDownTimer1.Tick
        Me.Text = Math.Round(Me.CountDownTimer1.TimeLeft.TotalSeconds, 1)
    End Sub
    And here is the code for the timer itself:
    Code:
    Public Class CountDownTimer
    Inherits System.ComponentModel.Component
    Sub New()
        AddHandler timer.Tick, AddressOf ontick
        timer.Start()
        InitializeComponent()
    End Sub
    Sub New(ByVal Time As String)
        MyClass.New(TimeSpan.Parse(Time))
    End Sub
    Sub New(ByVal Time As TimeSpan)
        MyClass.New()
        Me.Time = Time
    End Sub
    Public Event OnElapsed As EventHandler
    Public Event Tick As EventHandler
    Public Property Interval() As Integer
        Get
            Return timer.Interval
        End Get
        Set(ByVal value As Integer)
            timer.Interval = value
        End Set
    End Property

    Private _time As TimeSpan
    Public Property Time() As TimeSpan
        Get
            Return _time
        End Get
        Set(ByVal value As TimeSpan)
            _time = value
        End Set
    End Property

    Private watch As New Stopwatch
    Private timer As New Windows.Forms.Timer() With {.Interval = 100, .Enabled = False}
    Private Sub ontick()
        If watch.Elapsed >= Time Then
            Me.Stop()
            RaiseEvent OnElapsed(Me, EventArgs.Empty)
        End If
        RaiseEvent Tick(Me, EventArgs.Empty)
    End Sub
    Sub Start()
        watch.Start()
        timer.Start()
    End Sub
    Sub [Stop]()
        watch.Stop()
        timer.Stop()
    End Sub
    Sub Reset()
        watch.Reset()
    End Sub
    Public ReadOnly Property TimeLeft() As TimeSpan
        Get
            Return If(watch.Elapsed > Time, New TimeSpan(0), Time - watch.Elapsed)
        End Get
    End Property
    Public ReadOnly Property Elapsed() As TimeSpan
        Get
            Return If(watch.Elapsed > Time, Time, watch.Elapsed)
        End Get
    End Property

    Public Sub New(ByVal container As System.ComponentModel.IContainer)
        MyClass.New()
        If (container IsNot Nothing) Then
            container.Add(Me)
        End If
    End Sub
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        Try
            If disposing AndAlso components IsNot Nothing Then
                components.Dispose()
            End If
        Finally
            MyBase.Dispose(disposing)
        End Try
    End Sub

    Private components As System.ComponentModel.IContainer
    Private Sub InitializeComponent()
        components = New System.ComponentModel.Container()
    End Sub

End Class
    Feel free to use both, just give credit. Also if anyone can find problems with the calculator, please tell me.
     
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  3. Unread #2 - Apr 16, 2008 at 4:37 PM
  4. Blupig
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    [VB 2008] Calculator and count down timer sources
    I haven't met one person in the world yet who doesn't like a decent countdown source :D
    +1
     
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