Question

错误代码：Decimal price = Decimal.Parse(txtprice.Text);

private void button1_Click(object sender, EventArgs e)
    {
        decimal height1 = decimal.Parse(txtnorthheight.Text);

        decimal length1 = decimal.Parse(txtnorthlength.Text);

        decimal area1 = height1 * length1;

        lblnortharea.Text = area1.ToString("n");

        decimal height2 = decimal.Parse(txtsouthheight.Text);

        decimal length2 = decimal.Parse(txtsouthlength.Text);

        decimal area2 = height2 * length2;

        lblsoutharea.Text = area2.ToString("n");


        decimal height3 = decimal.Parse(txteasthheight.Text);

        decimal length3 = decimal.Parse(txteasthlength.Text);

        decimal area3 = height3 * length3;

        lbleastarea.Text = area3.ToString("n");


        decimal height4 = decimal.Parse(txtwesthheight.Text);

        decimal length4 = decimal.Parse(txtwestlength.Text);

        decimal area4 = height4 * length4;

        lblwestharea.Text = area4.ToString("n");


        decimal height5 = decimal.Parse(txtwinheight.Text);

        decimal length5 = decimal.Parse(txtwinlength.Text);

        decimal area5 = height5 * length5;

        lblwinharea.Text = area5.ToString("n");

        decimal areatotal = (area1 + area2 + area3 + area4) - area5;

        lbltotalarea.Text = areatotal.ToString("n");

        decimal Heightt = (height1 + height2 + height3 + height4) - height5;
        decimal Legntht = (length1 + length2 + length3 + length4) - length5;

        Height2.Text = Heightt.ToString("n");
        Legnth.Text = Legntht.ToString("n");

        Decimal price = Decimal.Parse(txtprice.Text);

        Decimal undercoat = Decimal.Parse(txtunder.Text);

        decimal roomcost = (Heightt * Legntht) * price * undercoat;

        txtprice.Text = roomcost.ToString("c");

        decimal Vattotal = (25 % roomcost);

        lblvat.Text = Vattotal.ToString("c");

        Decimal vt = Vattotal + roomcost;

        lblbt.Text = vt.ToString("c");
    }

工作没有问题，但现在我正在重建程序由于一些错误，这行代码不想工作。有任何想法吗？

如果要求，我可以发布整个269行代码以及visual studio错误代码。

Answer 1

如果输入字符串的格式不能解析为FormatException，则

Decimal.Parse(string s)会抛出decimal。

您可以改为使用Decimal.TryParse(string s, out Decimal d)。

decimal d = 0;
if(Decimal.TryParse(txtnorthheight.Text, out d))
{
    // If the string could be parsed, d contains the value.
    // otherwise TryParse returns false.
}

为了使其易于管理，您可能希望将功能分解为更小的部分并首先解析输入。否则，如果整个方法中存在多个点，则由于输入无效而可能必须退出，逻辑会变得混乱。

另一种方法是使用验证来确保只能输入某些类型的值。 Here是有关Windows窗体验证的一些文档。（我无法确定您是否正在使用Forms或ASP.NET。）

转换为小数时的系统格式错误

1 个答案: