输入为0.00时，RegularExpression验证在ModelState.IsValid失败 [英] RegularExpression validation fails at ModelState.IsValid when input is 0.00

问题描述

我遇到类似于此问题的问题

我正在使用 MVC .我在ViewModel中添加了正则表达式，以强制用户输入一个1或2个小数位的数字.我认为我的正则表达式中肯定有错误，但是同一条语句在其他地方也可以正常工作.

I'm using MVC. I have added a regular expression in my ViewModel to force the users to enter a number with 1 or 2 decimal places. I am thinking there must be an error in my Regex but the same statement is working fine elsewhere.

如果我输入0.00作为我的费率，则在我提交表单时， ModelState.IsValid返回为假.

If I put in 0.00 as my rate, when I submit my form, ModelState.IsValid returns as false.

[RegularExpression(@"^(\d+\.\d{1,2})$", ErrorMessage = "Please enter valid rate with 1 or 2 decimal places")]
public double DecimalRate { get; set; }

• 如果我输入任何无效的输入，它的行为将与预期的一样，并显示正确的错误消息，而不是让我保存页面
• 如果我输入有效的输入(0.00以外的数字)，则可以正确保存.
• 如果我完全删除了正则表达式，则将0.00视为有效输入，它保存正确.

根据此问题中的建议，我已验证此比率导致了通过在Visual Studio中的ModelState.IsValid上设置调试并检查错误来实现错误.

As per a suggestion in this question, I have verified that this rate is causing the error by setting a debug at ModelState.IsValid in Visual Studio and checking the errors.

我预感这可能与 double 类型的属性有关?

I have a hunch it might have something to do with the attribute being of type double?

推荐答案

之所以会发生这种情况，是因为您属性的数据类型是 double (不是 string )，所以它不会t代表一系列字符.它代表一个数值.如果您输入的是 0.00 ，则它将表示值 0 ，并且与正则表达式不匹配.我怀疑您也会对 3.00 这样的数字遇到相同的问题.

This is happening because your property's data type is double (not string), so it doesn't represent a series of characters. It represents a numerical value. If your input is 0.00, then it will represent the value 0, and not match the regex. I suspect you will encounter the same issue for numbers like 3.00 as well.

如果您需要用户输入采用特定格式，请将字段更改为 string ，然后在需要时使用 Convert.ToDouble()将其转换为数字.

If you need the user's inputs to be in a specific format, change your field to a string and then use Convert.ToDouble() when and if you need to convert it to a number.

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