字符串为空时，将字符串值替换为“ 0”

问题描述

我要从文本框中获取一个值并将其转换为十进制。但是，文本框值可以为空。因此，我该如何处理文本框中的空字符串？

I'm taking a value from a textbox and converting it to decimal. But, the textbox value could be empty. So, how could I handle empty strings from the textbox?

不幸的是，我有大约50个文本框要处理，因此诸如在IF条件下检查null这样的答案就可以了。帮帮我。如果我使用所有这些IF条件，我的代码将很难看。

Unfortunately I have around 50 textboxes to deal with, so answers like 'check for null with IF condition' won't help me. My code will look ugly if I use all those IF conditions.

我有这个

Convert.ToDecimal(txtSample.Text)

要处理空值，我这样做了

To handle nulls, I did this

Convert.ToDecimal(txtSample.Text = string.IsNullOrEmpty(txtSample.Text) ? "0" : txtSample.Text)

但是，上面的代码在文本框中显示为 0。用户不想看到 0。另一个解决方案是将文本框值转换为变量，然后将变量转换如下。

But, the above code is displaying '0' in the textbox. User does not want to see '0'. Another solution is to take text box value into a variable and convert the variable like below.

string variable = txtSample.Text;
Convert.ToDecimal(variable = string.IsNullOrEmpty(variable) ? "0" : variable)

But again, I do not want to define around 50 variables. I am looking for some piece of code that handles null values during conversion without adding the extra line of code.

推荐答案

这是因为您的语句将新值分配给 txtSample.Text （当您执行 txtSample.Text = ... 时）。只需删除分配：

This is because your statement is assigning the new value to txtSample.Text (when you do txtSample.Text = ...). Just remove the assignment:

Convert.ToDecimal(string.IsNullOrEmpty(txtSample.Text) ? "0" : txtSample.Text)

如果要处理的文本字段很多，可以使事情变得简单，可以定义扩展方法：

To make things easier if you have many text fields to handle, you can define an extension method :

public static string ZeroIfEmpty(this string s)
{
    return string.IsNullOrEmpty(s) ? "0" : s;
}

并像这样使用它：

Convert.ToDecimal(txtSample.Text.ZeroIfEmpty())

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