Question

我试图获得一个月和一年的最后一天，但我无法找到我的代码中的错误...

我有这个功能

  Private Function Ultim_dia(mes As String) As String
    Dim ultim As String
    ultim = 1
    Select Case (mes)
        Case 1, 3, 5, 7, 8, 10, 12
            ultim = "31"

        Case 4, 6, 9, 11
            ultim = "30"

        Case 2
            If ((mes) Mod 4) = 0 Then
                ultim = "29"

            Else
                ultim = "28"

            End If
    End Select
    Return ultim
End Function

在我的OnclickButton上我有这段代码

 Dim ultim As String
    ultim = tbMes.Text


    Ultim_dia(ultim)
    Select Case (ultim)
        Case "29"
            Me.lb_UltimoDia.Text = "29"
        Case "28"
            Me.lb_UltimoDia.Text = "28"
        Case "30"
            Me.lb_UltimoDia.Text = "30"
        Case "31"
            Me.lb_UltimoDia.Text = "31"
    End Select

我不知道我错在哪里，我发现自己不能在任何地方使用我的一年......我不知道这是不是问题

我希望你能帮助我，这让我发疯了......

Answer 1

要获取当月的天数，请使用DaysInMonth内置功能。</ p>

Dim currentDate As Date = Date.Now
Dim lastDayOfMo = Date.DaysInMonth(currentDate.Year, currentDate.Month)

Answer 2

给定月份和年份（月份= 10年和年份=＆＃39; 2014年＆＃39;）

创建下个月第一天的新日期

Dim q as new date("1", month+1, "2014")

然后做一个负日期的日期加载

dim a as new date = dateadd("d",-1,q)

那应该会给你原始月份的最后日期。

Answer 3

在VBA中测试过，可能也适用于VB.NET：

Function LastDayOfMonth(theMonth As Long, theYear As Long) As Date
    LastDayOfMonth = DateSerial(theYear, theMonth + 1, 0)
End Function

例如，要获得2014年10月的最后一天：

Dim d As Date
d = LastDayOfMonth(10, 2014) ' returns 31 Oct 2014

Answer 4

按钮单击将调用将返回传递给该函数的年份和月份中的no.of天数的函数。

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
      Dim ultim As String = noOfdays(1989, 8)
 End Sub
 '<-- function
 Public Function noOfdays(ByVal year As Integer, ByVal month As Integer) As String
   Try
        noOfdays = Date.DaysInMonth(year, month)
    Catch ex As Exception
        MsgBox(ex.ToString)
    End Try
 End Function

查找一个月和一年VisualBasic的最后一天

4 个答案: