Question

这还是一个菜鸟，所以请耐心等待。我的问题的简短版本是我有一个月份日历，其中包含一系列日期并将它们添加到标签

Dim iStart as DateTime = MonthCalendar1.SelectionRange.Start.ToShortDatestring
Dim iEnd as DateTime = MonthCalendar1.SelectionRange.End.ToShortDatestring
Dim iCount as DateTime = iStart

While iCount <= iEnd
    iCount = iCount.AddDays(1)
    Lable1.Text = Label1.Text & iCount & vbNewLine
End With

现在完美无缺。但这是我想要添加到数据库的单个记录的一部分。所以考虑做一个For Each循环，但得到上面提到的错误 - 类型的值＆＃39; Char＆＃39;无法转换为＆＃39;日期＆＃39; 这是代码的开头

For Each iCount in label1.text    'This is where the error comes up

请帮忙

Answer 1

由于你已经使用了一个常见的分隔符“vbNewLine”，尝试使用Split来检索它们，尽管你最好首先使用像Plutonix状态这样的List（of T）。 / p>

这是一个使用我以前测试的控制台应用程序的示例，因此UI元素不存在，并被等效变量替换。

使用Split

Sub Main()
    Dim iStart As DateTime = New DateTime(2014, 1, 1)
    Dim iEnd As DateTime = New DateTime(2014, 1, 15)
    Dim iCount As DateTime = iStart
    Dim LabelText As String
    Dim temp()

    While iCount <= iEnd
        iCount = iCount.AddDays(1)
        LabelText = LabelText & iCount & vbNewLine
    End While
    temp = LabelText.Split(vbNewLine) 'This seperates the single string back to individual entrys
    For Each s As String In temp
        Console.WriteLine(DateTime.Parse(s)) 'Add to DataBase here.
    Next

End Sub

使用List(of DateTime)无需重新转换即可轻松实现。

Sub Main()
    Dim iStart As DateTime = New DateTime(2014, 1, 1)
    Dim iEnd As DateTime = New DateTime(2014, 1, 15)
    Dim iCount As DateTime = iStart
    Dim LabelText As String
    Dim tempDate As List(Of DateTime) = New List(Of DateTime)

    While iCount <= iEnd
        iCount = iCount.AddDays(1)
        tempDate.Add(iCount)  'Just add it here no conversion necessary
        LabelText = LabelText & iCount & vbNewLine
    End While

    For Each d As Date In tempDate
        Console.WriteLine(d) 'Add to Database here using Console.WriteLine as example
    Next
End Sub

Answer 2

您可以将其转换为一行（长）代码：

Dim Days() As DateTime = Enumerable.Range(0, (MonthCalendar1.SelectionRange.End.Date - MonthCalendar1.SelectionRange.Start.Date).Days).Select(Function(i) MonthCalendar1.SelectionRange.Start.AddDays(i)).ToArray()

为了便于阅读，将其分解一下：

Dim start As DateTime = MonthCalendar1.SelectionRange.Start.Date
Dim stop As DateTime = MonthCalendar1.SelectionRange.End.Date
Dim Days() As DateTime = Enumerable.Range(0, (stop - start).Days).
                          Select(Function(i) start.AddDays(i)).ToArray()

然后从您已有的Days()数组构建标签字符串，而不是先构建标签并稍后重建数组。

Lable1.Text = String.Join(vbCrLf, Days)

vb.net错误 - 类型＆＃39; Char＆＃39;的值无法转换为＆＃39;日期＆＃39;

2 个答案: