Question

我写了这个样本来展示我的问题。我有一个进度条（在异步Sub中但问题也在同步中）当我增加价值时，我在视频上看不到任何内容。

只有在Sub的末尾才能看到现在位于值顶部的进度条。为什么？

Private Sub Btn_ProgressBar_Click(sender As Object, e As RoutedEventArgs) Handles Btn_ProgressBar.Click

    Me.BarraProgresso.Minimum = 0
    Me.BarraProgresso.Maximum = 100
    Me.BarraProgresso.Value = 0

    For i As Integer = 1 To 1000
        If i / 100 = CInt(i / 100) Then
            Me.BarraProgresso.Value = CInt(i / 100)
        End If

        For KK As Integer = 0 To 9000000
            Dim _MyApple As String = "Red Apple"
        Next
    Next

End Sub

Answer 1

您的按钮单击处理程序在UI线程上同步调用，您忙着等待。在处理程序返回之前不会呈现任何内容。这样做效果更好：

SELECT values.* FROM
(SELECT MAX(id) AS id FROM miscall_records GROUP BY mobile_no) AS keys
LEFT JOIN miscall_records AS values
ON keys.id = values.id

这是C＃而不是VB，但我认为翻译是可管理的。： - ）

UWP - ProgressBar可见值仅在Sub的末尾更改

1 个答案: