如何忽略小數點后VB.net中0后的值？

Question

我將小數變量四舍五入到4位。

Dim a As Decimal = Math.Round(b, 4, MidpointRounding.AwayFromZero)

如果值是5400.40019 ，我將得到5400.4002 。 但是我不希望小數點后0后面的值。 例如，當值為5400.4001 ，我只需要5400.4000 。 如果值為5400.0412 ， 5400.0000需要5400.0000 。

我怎樣才能？

Answer 1

我不確定沒有字符串操作是否可以實現。 這應該為您提供所需的結果。 它將小數點四舍五入到小數點后四位，將其轉換為字符串，然后迭代字符串的每個字符以搜索小數位，然后搜索小數點后的第一個零。

    Dim b As Decimal = 5400.40019D
    Dim a As Decimal = Math.Round(b, 4, MidpointRounding.AwayFromZero)
    Dim s As String = a.ToString
    Dim s2 As String = ""
    Dim bDecimalPointFound As Boolean
    Dim bZeroFound As Boolean

    For i As Int32 = 0 To s.Length - 1
        Dim sChar As String = s.Substring(i, 1)

        If bDecimalPointFound = True Then
            If sChar = "0" Then bZeroFound = True
            s2 &= If(bZeroFound = True, "0", sChar)
        Else
            s2 &= sChar
            bDecimalPointFound = (sChar = ".")
        End If
    Next

    Dim c As Decimal = Convert.ToDecimal(s2)

Answer 2

試試這個方法

Public Function CustomFormater(b As Decimal) As Decimal
    Dim a As Decimal = Math.Round(b, 4, MidpointRounding.AwayFromZero)
    Dim pre As Int32 = Convert.ToInt32(a.ToString().Split(".")(1))
    Dim result As Int32 = If(pre Mod 1000 >= 500, pre + 1000 - pre Mod 1000, pre - pre Mod 1000)
    Dim output As Decimal = Math.Round(Convert.ToDecimal(a.ToString().Split(".")(0) + "." + result.ToString()), 4, MidpointRounding.AwayFromZero)
    Return output
End Function

您只需要在輸入十進制值時調用此方法即可。

例如

Dim b As Decimal = 5400.40019
MessageBox.Show("done" + CustomFormater(b).ToString())