Background worker : BackgroundWorker « GUI « VB.Net Tutorial






Background worker
Imports System.Windows.Forms


public class BackgroundWorker
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class
Public Class Form1
    ' Display the current time.
    Private Sub tmrUpdateClock_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrUpdateClock.Tick
        lblTime.Text = Now.ToString("T")
    End Sub

    ' Start the asynchronous calculation.
    Private Sub btnGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGo.Click
        btnGo.Enabled = False
        lblWorking.Text = "Working..."
        Me.Cursor = Cursors.WaitCursor
        Application.DoEvents()

        bgwLongCalculation.RunWorkerAsync(5)
    End Sub

    Private Sub bgwLongCalculation_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgwLongCalculation.DoWork

        For i As Integer = 0 To 100000
            For j As Integer = 0 To 100000
                For k As Integer = 0 To 100000
        
                Next k
            Next j
        Next i
    End Sub

    ' The long task is done.
    Private Sub bgwLongCalculation_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles bgwLongCalculation.RunWorkerCompleted
        btnGo.Enabled = True
        lblWorking.Text = "Done..."
        Me.Cursor = Cursors.Default
    End Sub
End Class
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Public Class Form1
    Inherits System.Windows.Forms.Form

    'Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub

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

    '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.components = New System.ComponentModel.Container
        Me.btnGo = New System.Windows.Forms.Button
        Me.lblTime = New System.Windows.Forms.Label
        Me.tmrUpdateClock = New System.Windows.Forms.Timer(Me.components)
        Me.bgwLongCalculation = New System.ComponentModel.BackgroundWorker
        Me.lblWorking = New System.Windows.Forms.Label
        Me.SuspendLayout()
        '
        'btnGo
        '
        Me.btnGo.Location = New System.Drawing.Point(8, 8)
        Me.btnGo.Name = "btnGo"
        Me.btnGo.Size = New System.Drawing.Size(48, 23)
        Me.btnGo.TabIndex = 0
        Me.btnGo.Text = "Go"
        '
        'lblTime
        '
        Me.lblTime.AutoSize = True
        Me.lblTime.Location = New System.Drawing.Point(232, 8)
        Me.lblTime.Name = "lblTime"
        Me.lblTime.Size = New System.Drawing.Size(36, 13)
        Me.lblTime.TabIndex = 1
        Me.lblTime.Text = "lblTime"
        '
        'tmrUpdateClock
        '
        Me.tmrUpdateClock.Enabled = True
        Me.tmrUpdateClock.Interval = 250
        '
        'bgwLongCalculation
        '
        '
        'lblWorking
        '
        Me.lblWorking.Location = New System.Drawing.Point(80, 8)
        Me.lblWorking.Name = "lblWorking"
        Me.lblWorking.Size = New System.Drawing.Size(112, 24)
        Me.lblWorking.TabIndex = 2
        Me.lblWorking.TextAlign = System.Drawing.ContentAlignment.MiddleLeft
        '
        'Form1
        '
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(292, 80)
        Me.Controls.Add(Me.lblWorking)
        Me.Controls.Add(Me.lblTime)
        Me.Controls.Add(Me.btnGo)
        Me.Name = "Form1"
        Me.Text = "UseBackgroundWorker"
        Me.ResumeLayout(False)
        Me.PerformLayout()

    End Sub
    Friend WithEvents btnGo As System.Windows.Forms.Button
    Friend WithEvents lblTime As System.Windows.Forms.Label
    Friend WithEvents tmrUpdateClock As System.Windows.Forms.Timer
    Friend WithEvents bgwLongCalculation As System.ComponentModel.BackgroundWorker
    Friend WithEvents lblWorking As System.Windows.Forms.Label

End Class








14.92.BackgroundWorker
14.92.1.Background workerBackground worker
14.92.2.Long process and GUILong process and GUI