從十進制字符串的錯誤

Question

我有一個文本框，其值爲0.00，然後我得到了一個錯誤轉換...但我 已經做了0.00不是從文本框，它的工作..如何修復這個問題？

Dim _Total, _Deduct, _Charges As String 
    Dim _sss, _tax, _pf, _ph, _loan, _others, _hdmf, _cola, _allowance As Decimal 

這行，如果文本框和註釋此行是工作..但我用這個不工作..

_sss = txtSSS.Text : _ph = txtPH.Text : _tax = txtInTax.Text : _pf = txtPF.Text 
    _loan = txtLoan.Text : _hdmf = txtHDMF.Text : _others = txtOther.Text 
    _cola = txtCola.ToString : _allowance = txtAllowance.ToString 

這行是我給出的示例值...相同的值，但文本框沒有工作..這是工作

'This code when I uncomment.. this work.. 
    '_sss = "0.00": _ph = "0.00" : _tax = "0.00" : _pf = "0.00" 
    '_loan = "0.00" : _hdmf = "50.00" : _others = "0.00" 
    '_cola = "0.00" : _allowance = "0.00" 

    _Charges = CDec(_cola) + CDec(_allowance) 
    _Deduct = CDec(_sss) + CDec(_tax) + CDec(_pf) + CDec(_ph) + CDec(_loan) + CDec(_hdmf) + CDec(_others) 

    _Total = CDec(_Charges) - CDec(_Deduct) 

    lblDeduct.Text = Format((_Deduct), "currency") 
    lblTotal.Text = FormatCurrency((_Total), 2, TriState.True, TriState.False, TriState.True) 

Answer 1

使用Decimal.TryParse：

<!-- language : lang-vb --> 
If Not Decimal.TryParse(txtSSS.Text, _sss) Then 
    ' do something if the value doesn't convert 
End If 

---

根據你的評論和玩你的代碼，看看這是否適合你（我用0作爲默認值）。如果您沒有打開Option Strict，請爲自己做個忙，然後這樣做。

從以上Option Strict鏈路：

隱範圍限制數據類型轉換到僅擴大轉換，不允許後期綁定，並禁止導致Object類型隱式類型。

Private Sub CalculateCurrency() 
    If Not Decimal.TryParse(txtSSS.Text, _sss) Then _sss = 0D 
    If Not Decimal.TryParse(txtPH.Text, _ph) Then _ph = 0D 
    If Not Decimal.TryParse(txtInTax.Text, _tax) Then _tax = 0D 
    If Not Decimal.TryParse(txtPF.Text, _pf) Then _pf = 0D 
    If Not Decimal.TryParse(txtLoan.Text, _loan) Then _loan = 0D 
    If Not Decimal.TryParse(txtHDMF.Text, _hdmf) Then _hdmf = 0D 
    If Not Decimal.TryParse(txtOther.Text, _others) Then _others = 0D 
    If Not Decimal.TryParse(txtCola.Text, _cola) Then _cola = 0D 
    If Not Decimal.TryParse(txtAllowance.Text, _allowance) Then _allowance = 0D 

    _Charges = CStr(_cola + _allowance) 

    _Deduct = CStr(_sss + _tax + _pf + _ph + _loan + _hdmf + _others) 

    _Total = CStr(CDec(_Charges) - CDec(_Deduct)) 

    lblDeduct.Text = Format((_Deduct), "currency") 
    lblTotal.Text = FormatCurrency((_Total), 2, TriState.True, TriState.False, TriState.True) 
End Sub