asp.net c# 中给定的输入字符串格式不正确

Question

我正在尝试读取文本框字段值并检查它们是否为空并分配零整数值。

然后我将 everytextbox.text 分配给整数值。但这里显示错误，因为输入字符串的格式不正确。如何克服这个

 if (txtYearofPurchased.Text == null || 
     txtMonthofPurchased.Text == null || 
     txtCurrentMonthEnd.Text == null || 
     txtCurrentYearEnd.Text == null|| 
     txtCost.Text == null || 
     txtDepnRate1.Text ==null)
    {
        txtYearofPurchased.Text = Convert.ToString(0);
        txtMonthofPurchased.Text = Convert.ToString(0);
        txtCurrentMonthEnd.Text= Convert.ToString(0);
        txtCost.Text= Convert.ToString(0);
        txtDepnRate1.Text = Convert.ToString(0);
    }

    int yearofpurchase = Int32.Parse(txtYearofPurchased.Text);
    int monthofpurchase = Int32.Parse(txtMonthofPurchased.Text);
    int CurrentMonth = Int32.Parse(txtCurrentMonthEnd.Text);// present month
    int CurrentYearend = Int32.Parse(txtCurrentYearEnd.Text);// present year
    float Cost = Int32.Parse(txtCost.Text);
    float DepnRate1 = Int32.Parse(txtDepnRate1.Text) / 100;
    float ad = AD();

Answer 1

两件事：

您没有使用 if 的 else 块，所以您使用的是 int.Parse，即使它们已被检测为无效。
使用 int.TryParse 而不是 null-check+int.Parse 因为 Text 属性永远不会为 null，所以它 returns String.Empty 代替。而且你还必须处理无效输入。

像这样：

int yearofpurchase,monthofpurchase,CurrentMonth,CurrentYearend;
float Cost,DepnRate1,ad;
bool validYearOfPurchase = int.TryParse(txtYearofPurchased.Text, out yearofpurchase);
bool validMonthOfPurchase = int.TryParse(txtMonthofPurchased.Text, out monthofpurchase);
bool validCurrentMonth = int.TryParse(txtCurrentMonthEnd.Text, out CurrentMonth);
bool validCurrentYearend= int.TryParse(txtCurrentYearEnd.Text, out CurrentYearend);
if(!validYearOfPurchase || !validMonthOfPurchas || !validCurrentMonth || !validCurrentYearend)
{
    txtYearofPurchased.Text = "0";
    txtMonthofPurchased.Text = "0";
    txtCurrentMonthEnd.Text = "0";
    txtCurrentYearEnd.Text = "0";
}
else
{
    // ...
}

Answer 2

 int yearofpurchase;
    int monthofpurchase;
    int CurrentMonth;
    int CurrentYearend;
    float Cost;
    float DiffinAccumdepnatbeggining;
    float DepnRate1;
    bool res = int.TryParse(txtYearofPurchased.Text, out yearofpurchase);
    bool MOP = int.TryParse(txtMonthofPurchased.Text, out monthofpurchase);
    bool CM = int.TryParse(txtCurrentMonthEnd.Text, out CurrentMonth);// present month
    bool CYE = int.TryParse(txtCurrentYearEnd.Text, out CurrentYearend);// present year
    bool cost = float.TryParse(txtCost.Text, out Cost);
    bool DCB = float.TryParse(txtDiffinAccumdepnatbeggining.Text, out DiffinAccumdepnatbeggining);
    bool DR = float.TryParse(txtDepnRate1.Text, out DepnRate1);

Answer 3

通常TextBox.Text不能是null，而是一个空字符串。另外 Convert.ToString(0) 是 "0"，所以我会像这样更改您的代码：

if (String.IsNullOrWhitespace(txtYearofPurchased.Text) || 
    String.IsNullOrWhitespace(txtMonthofPurchased.Text) || 
    String.IsNullOrWhitespace(txtCurrentMonthEnd.Text) || 
    String.IsNullOrWhitespace(txtCurrentYearEnd.Text) || 
    String.IsNullOrWhitespace(txtCost.Text) || 
    String.IsNullOrWhitespace(txtDepnRate1.Text))
{
    txtYearofPurchased.Text = "0";
    txtMonthofPurchased.Text = "0";
    txtCurrentMonthEnd.Text= "0";
    txtCost.Text= "0";
    txtDepnRate1.Text = "0";
}

int yearofpurchase = Int32.Parse(txtYearofPurchased.Text);
int monthofpurchase = Int32.Parse(txtMonthofPurchased.Text);
int CurrentMonth = Int32.Parse(txtCurrentMonthEnd.Text);// present month
int CurrentYearend = Int32.Parse(txtCurrentYearEnd.Text);// present year
float Cost = Int32.Parse(txtCost.Text);
float DepnRate1 = Int32.Parse(txtDepnRate1.Text) / 100;

asp.net c# 中给定的输入字符串格式不正确

the given input string was not in a correct format in asp.net c#

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