CODEWITHSUNDEEP
vb.netasynchronous
uqji
uqji

Reputation: 195

Asynchronous task regarding data loading, UI freezing

I'm writing a data visual tool for my team and need to read a data file once the windows Form opens. The binary data file is large and can take quite a few seconds to load depending on connection speed of the user's PC to the file's network location. My limited asynchronous programming knowledge produced the following framework. The data loading still freezes the UI, which is the thing I would like to avoid. Can someone give some help on this matter?

Public Class Form1

Public db_path as string = "db path string"

Private Async Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
    TextBox1.Text = "Loading..."
    Dim sample_num As Integer = Await read_DB(db_path)
    TextBox1.Text = "Sample count: " & sample_num.ToString
End Sub

Private Async Function read_DB(db_path as String) As Task(Of Integer)
    Dim sample_num As Integer = 0
    If (File.Exists(db_path)) Then
        Try
           Using reader As BinaryReader = New BinaryReader(File.Open(db_path, FileMode.Open, FileAccess.Read))
                sample_num = reader.ReadInt32()

                ' Read the DB file here

                Next

            End Using

        Catch Ex As Exception

        Finally

        End Try
    Else

    End If
    Return sample_num

End Function

End Class

Upvotes: 0

Views: 94

Answers (1)

Nauman Mustafa
Nauman Mustafa

Reputation: 103

Here is what you should do

Public Class Form1

    Public db_path As String = "db path string"

    Private Async Sub Form1_Shown(sender As Object, e As EventArgs) Handles Me.Shown
        TextBox1.Text = "Loading..."
        Dim sample_num As Integer
        Await Task.Run(Sub() sample_num = read_DB(db_path))
        TextBox1.Text = "Sample count: " & sample_num.ToString
    End Sub

    Private Function read_DB(db_path As String) As Integer
        Dim sample_num As Integer = 0
        If (File.Exists(db_path)) Then
            Try
                Using reader As BinaryReader = New BinaryReader(File.Open(db_path, FileMode.Open, FileAccess.Read))
                    sample_num = reader.ReadInt32()

                    ' Read the DB file here

                    Next

                End Using

            Catch Ex As Exception

            Finally

            End Try
        Else

        End If
        Return sample_num

    End Function

End Class

Upvotes: 1

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