[RaggiTech]

بالطبع اتضحت الرؤيا لك الآن أكثر وأكثر


تعال نزيد من بعض التلميحات حول الموضوع


نضع هذه الخصائص فى حدث تحميل الفورم

كود :

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Me.BackgroundWorker1.WorkerReportsProgress = True
Me.BackgroundWorker1.WorkerSupportsCancellation = True
Me.ProgressBar1.Minimum = 0
Me.ProgressBar1.Maximum = 100

End Sub

لقد أزدنا فى حدث التحميل أن نشطنا خاصية WorkerSupportsCancellation للعنصر

كود :

Me.BackgroundWorker1.WorkerSupportsCancellation = True

==========================================

نجعل الكود للحدث DoWork

كود :

Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork

For I As Integer = 0 To 100
If Me.BackgroundWorker1.CancellationPending Then
e.Cancel = True
Return
End If
Me.BackgroundWorker1.ReportProgress(I)
System.Threading.Thread.Sleep(100)
Next

End Sub

============================================

الحدث ProgressChanged كما هو

كود :

Private Sub BackgroundWorker1_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
Me.ProgressBar1.Value = e.ProgressPercentage
End Sub

================================================


جاء دور حدث جديد وهو RunWorkerCompleted ويتم فى حالة المهمة انتهت أو توقفت

كود :

Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted

If Not (e.Error Is Nothing) Then
MessageBox.Show("حدث خطأ")
ElseIf e.Cancelled Then
MessageBox.Show("تم الالغاء")
Else
MessageBox.Show("تمت العملية")
End If

End Sub

الكود واضح وما يحتاج شرح


=====================================

كود :

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Me.ProgressBar1.Value = 0
Me.BackgroundWorker1.RunWorkerAsync()

End Sub

حدث الزر Button2 الخاص بالغاء العملية

كود :

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

If Me.BackgroundWorker1.IsBusy Then

Me.BackgroundWorker1.CancelAsync()

End If

End Sub

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