Question

我在我的代码中使用计时器。我正在设置1s定时器，用于从arduino接收串行数据。现在，我想每1分钟写入excel文件。使用计时器。从根本上说它运作良好。每1秒写入excel。但我想每1分钟写一次。下面我发布了计时器代码。这是设置为1s。当1秒超过增量计数器并在文本框上显示计数值时。

如果计数值达到60意味着1分钟。然后写入excel表，否则继续增加。

这是我的代码部分

 Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Dim counter As Integer
        Try

            SerialPort1.Write("c")
            System.Threading.Thread.Sleep(250)
            Dim k As Double
            Dim value As String = SerialPort1.ReadLine()
            k = CDbl(distance)
            ListBoxSensor.Text = k

            Dim s As New Series
            s.Points.AddXY(1000, k)
            Chart1.Series.Add(s)
            Count_val.Text = counter

            If counter = 6 Then
                Dim headerText = ""
                Dim csvFile As String = IO.Path.Combine(My.Application.Info.DirectoryPath, "Current.csv")

                If Not IO.File.Exists((csvFile)) Then
                    headerText = "Date& time ,value, "

                End If

                Using outFile = My.Computer.FileSystem.OpenTextFileWriter(csvFile, True)
                    If headerText.Length > 0 Then
                        outFile.WriteLine(headerText)
                    End If
                    Dim y As String = DateAndTime.Now()
                    Dim x As String = y + "," + value
                    outFile.Write(x)

                End Using
            End If

        Catch ex As Exception

        End Try

    End Sub

Answer 1

在您的计时器中，将子计数器声明为静态。使用 Dim ，值范围是本地的，返回后将丢失。这意味着在每个tick 计数器始终为零。静态即使在返回后也会保留该值。

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
    Static counter As Integer = 0 'Initial value
    counter += 1 'increase for every tick

    Try
        ...
        ...
        If counter = 60 Then
            ...
            ...
        End If

    Catch ex As Exception
        MsgBox("Error in Timer1_Tick: " & ex.Message)
    End Try
End Sub

如何计算VB中的计时器值

1 个答案: