Programming Microsoft Visual Basic .NET/Programming Microsoft Visual Basic .NET (Microsoft Press)(X08-78517)(2002).bin/setup/vbnet/19 advanced win32 techniques/win32techniquesdemo/performancecounterform.vb

Text File | 2002-03-16 | 19.1 KB | 456 lines

Public Class PerformanceCounterForm
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Friend WithEvents txtOut As System.Windows.Forms.TextBox
    Friend WithEvents cboCategories As System.Windows.Forms.ComboBox
    Friend WithEvents Label1 As System.Windows.Forms.Label
    Friend WithEvents Label2 As System.Windows.Forms.Label
    Friend WithEvents cboCounters As System.Windows.Forms.ComboBox
    Friend WithEvents cboInstances As System.Windows.Forms.ComboBox
    Friend WithEvents Label3 As System.Windows.Forms.Label
    Friend WithEvents btnSysinfo As System.Windows.Forms.Button
    Friend WithEvents btnGetCategories As System.Windows.Forms.Button
    Friend WithEvents btnSamples As System.Windows.Forms.Button
    Friend WithEvents btnCreate As System.Windows.Forms.Button
    Friend WithEvents btnDestroy As System.Windows.Forms.Button
    Friend WithEvents btnDisplay As System.Windows.Forms.Button

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.Container

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.
    'Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Label3 = New System.Windows.Forms.Label()
        Me.txtOut = New System.Windows.Forms.TextBox()
        Me.btnSamples = New System.Windows.Forms.Button()
        Me.btnGetCategories = New System.Windows.Forms.Button()
        Me.btnSysinfo = New System.Windows.Forms.Button()
        Me.cboCounters = New System.Windows.Forms.ComboBox()
        Me.cboCategories = New System.Windows.Forms.ComboBox()
        Me.btnCreate = New System.Windows.Forms.Button()
        Me.btnDestroy = New System.Windows.Forms.Button()
        Me.cboInstances = New System.Windows.Forms.ComboBox()
        Me.Label1 = New System.Windows.Forms.Label()
        Me.Label2 = New System.Windows.Forms.Label()
        Me.btnDisplay = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        '
        'Label3
        '
        Me.Label3.Location = New System.Drawing.Point(160, 120)
        Me.Label3.Name = "Label3"
        Me.Label3.Size = New System.Drawing.Size(184, 16)
        Me.Label3.TabIndex = 3
        Me.Label3.Text = "Instances"
        '
        'txtOut
        '
        Me.txtOut.Anchor = (((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
                    Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right)
        Me.txtOut.Location = New System.Drawing.Point(160, 184)
        Me.txtOut.Multiline = True
        Me.txtOut.Name = "txtOut"
        Me.txtOut.ScrollBars = System.Windows.Forms.ScrollBars.Both
        Me.txtOut.Size = New System.Drawing.Size(360, 136)
        Me.txtOut.TabIndex = 1
        Me.txtOut.Text = ""
        '
        'btnSamples
        '
        Me.btnSamples.Location = New System.Drawing.Point(16, 64)
        Me.btnSamples.Name = "btnSamples"
        Me.btnSamples.Size = New System.Drawing.Size(120, 40)
        Me.btnSamples.TabIndex = 0
        Me.btnSamples.Text = "Get some samples"
        '
        'btnGetCategories
        '
        Me.btnGetCategories.Location = New System.Drawing.Point(16, 112)
        Me.btnGetCategories.Name = "btnGetCategories"
        Me.btnGetCategories.Size = New System.Drawing.Size(120, 40)
        Me.btnGetCategories.TabIndex = 0
        Me.btnGetCategories.Text = "Get Counter Categories"
        '
        'btnSysinfo
        '
        Me.btnSysinfo.Location = New System.Drawing.Point(16, 16)
        Me.btnSysinfo.Name = "btnSysinfo"
        Me.btnSysinfo.Size = New System.Drawing.Size(120, 40)
        Me.btnSysinfo.TabIndex = 0
        Me.btnSysinfo.Text = "Get some system info"
        '
        'cboCounters
        '
        Me.cboCounters.Anchor = ((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right)
        Me.cboCounters.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList
        Me.cboCounters.DropDownWidth = 360
        Me.cboCounters.Location = New System.Drawing.Point(160, 88)
        Me.cboCounters.Name = "cboCounters"
        Me.cboCounters.Size = New System.Drawing.Size(360, 26)
        Me.cboCounters.Sorted = True
        Me.cboCounters.TabIndex = 2
        '
        'cboCategories
        '
        Me.cboCategories.Anchor = ((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right)
        Me.cboCategories.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList
        Me.cboCategories.DropDownWidth = 360
        Me.cboCategories.Location = New System.Drawing.Point(160, 32)
        Me.cboCategories.Name = "cboCategories"
        Me.cboCategories.Size = New System.Drawing.Size(360, 26)
        Me.cboCategories.Sorted = True
        Me.cboCategories.TabIndex = 2
        '
        'btnCreate
        '
        Me.btnCreate.Location = New System.Drawing.Point(16, 160)
        Me.btnCreate.Name = "btnCreate"
        Me.btnCreate.Size = New System.Drawing.Size(120, 40)
        Me.btnCreate.TabIndex = 0
        Me.btnCreate.Text = "Create custom counters"
        '
        'btnDestroy
        '
        Me.btnDestroy.Location = New System.Drawing.Point(16, 256)
        Me.btnDestroy.Name = "btnDestroy"
        Me.btnDestroy.Size = New System.Drawing.Size(120, 40)
        Me.btnDestroy.TabIndex = 0
        Me.btnDestroy.Text = "Destroy custom conters"
        '
        'cboInstances
        '
        Me.cboInstances.Anchor = ((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right)
        Me.cboInstances.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList
        Me.cboInstances.DropDownWidth = 360
        Me.cboInstances.Location = New System.Drawing.Point(160, 144)
        Me.cboInstances.Name = "cboInstances"
        Me.cboInstances.Size = New System.Drawing.Size(360, 26)
        Me.cboInstances.Sorted = True
        Me.cboInstances.TabIndex = 2
        '
        'Label1
        '
        Me.Label1.Location = New System.Drawing.Point(160, 8)
        Me.Label1.Name = "Label1"
        Me.Label1.Size = New System.Drawing.Size(184, 16)
        Me.Label1.TabIndex = 3
        Me.Label1.Text = "Categories"
        '
        'Label2
        '
        Me.Label2.Location = New System.Drawing.Point(160, 64)
        Me.Label2.Name = "Label2"
        Me.Label2.Size = New System.Drawing.Size(184, 16)
        Me.Label2.TabIndex = 3
        Me.Label2.Text = "Counters"
        '
        'btnDisplay
        '
        Me.btnDisplay.Location = New System.Drawing.Point(16, 208)
        Me.btnDisplay.Name = "btnDisplay"
        Me.btnDisplay.Size = New System.Drawing.Size(120, 40)
        Me.btnDisplay.TabIndex = 0
        Me.btnDisplay.Text = "Display custom counters"
        '
        'PerformanceCounterForm
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(7, 17)
        Me.ClientSize = New System.Drawing.Size(536, 333)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.btnDisplay, Me.btnDestroy, Me.btnCreate, Me.btnSamples, Me.cboInstances, Me.Label3, Me.Label2, Me.cboCounters, Me.Label1, Me.cboCategories, Me.btnGetCategories, Me.txtOut, Me.btnSysinfo})
        Me.Font = New System.Drawing.Font("Microsoft Sans Serif", 11!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Name = "PerformanceCounterForm"
        Me.Text = "EventLogForm"
        Me.ResumeLayout(False)

    End Sub

#End Region

    ' demonstrates how you can read system info through performance counters

    Private Sub btnSysinfo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSysinfo.Click
        ' Create a few performance counters.
        Dim pcProcesses As New PerformanceCounter("System", "Processes")
        Dim pcThreads As New PerformanceCounter("System", "Threads")
        Dim pcFilesOpen As New PerformanceCounter("Server", "Files Opened Total")

        ' Display their values.
        txtOut.Text = ""
        LogMessage("Processes = " & pcProcesses.RawValue.ToString)
        LogMessage("Threads = " & pcThreads.RawValue.ToString)
        LogMessage("Files Open Total = " & pcFilesOpen.RawValue.ToString)

        ' Create specific instances.
        Dim pcHandles As New PerformanceCounter("Process", "Handle Count", "devenv")
        LogMessage("Devenv Handle Count = " & pcHandles.RawValue.ToString)

        ' make it point to another instance.
        pcHandles.CounterName = "Thread Count"
        pcHandles.InstanceName = "System"
        LogMessage("System Thread Count = " & pcHandles.RawValue.ToString)

        Dim pcDevenvCpuTime As New PerformanceCounter("Process", "% Processor Time", "devenv")
        LogMessage("Devenv % Processor Time = " & pcDevenvCpuTime.NextValue.ToString)
    End Sub

    Sub LogMessage(ByVal msg As String)
        txtOut.AppendText(msg & ControlChars.CrLf)
    End Sub

    ' demonstrates how you can sample a counter

    Private Sub btnSamples_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSamples.Click
        Dim pcSwitches As New PerformanceCounter("Thread", "Context Switches/sec", "_Total")
        ' Read the first sample.
        Dim cs1 As CounterSample = pcSwitches.NextSample
        ' Wait for some time.
        System.Threading.Thread.Sleep(1000)
        ' Read the second sample.
        Dim cs2 As CounterSample = pcSwitches.NextSample
        ' Evaluate the result.
        Dim result As Single = CounterSample.Calculate(cs1, cs2)
        LogMessage("Thread switches/sec = " & result.ToString)

        Dim i As Integer
        For i = 1 To 10
            System.Threading.Thread.Sleep(1000)
            ' Get a new sample after one second.
            Dim cs3 As CounterSample = pcSwitches.NextSample
            ' Evaluate "instantaneous" (moving) average.
            result = CounterSample.Calculate(cs2, cs3)
            LogMessage("Thread switches/sec = " & result.ToString)
            ' Evaluate average value since the first sample.
            result = CounterSample.Calculate(cs1, cs3)
            LogMessage("Average Thread switches/sec = " & result.ToString)
            ' Use most recent sample as the basis for next moving average.
            cs2 = cs3
        Next
    End Sub

    ' get all the counter categories

    Private Sub btnGetCategories_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGetCategories.Click
        Dim pcc As PerformanceCounterCategory

        cboCategories.Items.Clear()
        ' Store categories in the combobox, but display their name.
        cboCategories.DisplayMember = "CategoryName"
        ' Load the combobox with all category names.
        For Each pcc In PerformanceCounterCategory.GetCategories
            cboCategories.Items.Add(pcc)
        Next
        ' Select the first element.
        cboCategories.SelectedIndex = 0
    End Sub

    ' Fill the other two combobox controls when a category is selected.

    Private Sub cboCategories_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboCategories.SelectedIndexChanged
        Dim pcCat As PerformanceCounterCategory
        Dim pCnt As PerformanceCounter
        Dim instName As String

        ' Get a reference to the selected category
        pcCat = CType(cboCategories.SelectedItem, PerformanceCounterCategory)

        ' Fill cboCounters with the list of counters.
        cboCounters.Items.Clear()
        ' Get a collection of counters for this category
        Dim idcc As InstanceDataCollectionCollection = pcCat.ReadCategory

        ' Each element of this collection is associated with a counter.
        Dim cntName As String
        For Each cntName In idcc.Keys
            cboCounters.Items.Add(cntName)
        Next

        ' Fill cboInstances with the list of instances.
        cboInstances.Items.Clear()
        cboInstances.Items.Add("(all)")
        Try
            For Each instName In pcCat.GetInstanceNames
                cboInstances.Items.Add(instName)
            Next
        Catch ex As Exception
            ' nothing to do - ignore the error
        End Try

        ' select the first element in both comboboxes
        If cboCounters.Items.Count > 0 Then
            cboCounters.SelectedIndex = 0
        End If
        If cboInstances.Items.Count > 0 Then
            cboInstances.SelectedIndex = 0
        End If
    End Sub

    ' refresh display when a new counter/instance is selected

    Private Sub CounterInstanceChange(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboCounters.SelectedIndexChanged, cboInstances.SelectedIndexChanged
        ' Create the array of 1 or more PerformanceCounter objects
        Dim catName As String = CType(cboCategories.SelectedItem, PerformanceCounterCategory).CategoryName
        Dim cntName As String = cboCounters.SelectedItem.ToString

        ' Two cases

        If cboInstances.SelectedIndex > 0 Then
            ' One single instance
            Dim instName As String = cboInstances.SelectedItem.ToString
            ReDim counters(0)
            counters(0) = New PerformanceCounter(catName, cntName, instName)
        Else
            ' Multiple instances
            Dim pcCat As PerformanceCounterCategory
            pcCat = CType(cboCategories.SelectedItem, PerformanceCounterCategory)
            Dim instNames() As String = pcCat.GetInstanceNames
            ReDim counters(instNames.GetUpperBound(0))
            Dim i As Integer
            For i = 0 To UBound(counters)
                counters(i) = New PerformanceCounter(catName, cntName, instNames(i))
            Next
        End If

        RefreshValues()

    End Sub

    ' The list of counters to be refreshed
    Dim counters() As PerformanceCounter
    Dim samples() As CounterSample

    ' update the display of selected counters/instances
    Private Sub RefreshValues()
        Dim sb As New System.Text.StringBuilder(1000)
        Dim pCnt As PerformanceCounter

        ' Get the list of values
        For Each pCnt In counters
            sb.Append(pCnt.InstanceName)
            sb.Append(" = ")
            sb.Append(GetCounterValue(pCnt))
            sb.Append(ControlChars.CrLf)
        Next

        ' Display in textbox
        txtOut.Text = sb.ToString
    End Sub

    ' Get the value of a given PerformanceCounter object

    Private Function GetCounterValue(ByVal pCnt As PerformanceCounter) As String
        Select Case pCnt.CounterType
            Case PerformanceCounterType.NumberOfItems32, PerformanceCounterType.NumberOfItems64
                Return pCnt.RawValue.ToString
            Case PerformanceCounterType.RateOfCountsPerSecond32, PerformanceCounterType.RateOfCountsPerSecond64
                Return pCnt.NextValue.ToString
            Case PerformanceCounterType.AverageTimer32
                Return pCnt.NextValue.ToString
        End Select
    End Function

    ' create a new performance counter

    Private Sub btnCreate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCreate.Click
        Dim counters As New CounterCreationDataCollection()
        Dim ccd As CounterCreationData

        ' Exit if the category exists already.
        If PerformanceCounterCategory.Exists("MyApp") Then
            Exit Sub
        End If

        ' Define the first counter, then add it to the collection.
        ccd = New CounterCreationData("Flush operations", "Total number of flush operations", PerformanceCounterType.NumberOfItems32)
        counters.Add(ccd)

        ' Define the second counter, then add it to the collection.
        ccd = New CounterCreationData("Flush operations / sec", "Number of flush operations per second", PerformanceCounterType.RateOfCountsPerSecond32)
        counters.Add(ccd)

        ' Create the category and the counters in one operation.
        PerformanceCounterCategory.Create("MyApp", "Counters for MyApp program", counters)
    End Sub

    ' generate some custom values

    Private Sub btnDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplay.Click
        Dim pc1 As New PerformanceCounter("MyApp", "Flush operations", False)
        Dim pc2 As New PerformanceCounter("MyApp", "Flush operations / sec", False)
        Dim res As Single
        txtOut.Text = ""

        ' Assign a starting value.
        pc1.RawValue = 10
        pc2.RawValue = 10
        ' store an initial sample.
        Dim cs1 As CounterSample = pc2.NextSample

        ' Wait some time and increment values.
        System.Threading.Thread.Sleep(500)
        pc1.IncrementBy(15)
        pc2.IncrementBy(15)
        ' Display current values
        res = CounterSample.Calculate(cs1, pc2.NextSample)
        LogMessage("Flush operations = " & pc1.RawValue.ToString)
        LogMessage("Flush operations / sec = " & res.ToString)

        ' Wait some time and increment values.
        System.Threading.Thread.Sleep(500)
        pc1.IncrementBy(25)
        pc2.IncrementBy(25)
        ' Display current values
        res = CounterSample.Calculate(cs1, pc2.NextSample)
        LogMessage("Flush operations = " & pc1.RawValue.ToString)
        LogMessage("Flush operations / sec = " & res.ToString)

        Dim pc3 As New PerformanceCounter("MyApp", "Flush operations", False)
        ' Create a first instance.
        pc3.InstanceName = "First"
        pc3.RawValue = 10
        ' Create a second instance.
        pc3.InstanceName = "Second"
        pc3.RawValue = 20
        ' Display the value of the two instances.
        pc3.InstanceName = "First"
        Debug.WriteLine("First Instance = " & pc3.RawValue.ToString)
        pc3.InstanceName = "Second"
        Debug.WriteLine("Second Instance = " & pc3.RawValue.ToString)
    End Sub

    ' Destroy the custom category built previously.

    Private Sub btnDestroy_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDestroy.Click
        ' check whether the category exists.
        If PerformanceCounterCategory.Exists("MyApp") Then
            PerformanceCounterCategory.Delete("MyApp")
        End If
    End Sub
End Class