如何在NCalc.Expression中的字符串变量中转义单引号-反斜杠不起作用 [英] How to escape single quote within string variable in NCalc.Expression - Backslash didn't work

问题描述

我正在使用NCalc.Expression评估条件，该条件涉及与其中包含单引号的字符串值进行比较.在NCalc中，字符串使用单引号而不是双引号表示.

I am using NCalc.Expression to evaluate a condition which involves comparison with string values that contain single quote within them. In NCalc, string is represented using single quote instead of double quotes.

例如:

[variable1]=='Sample's Data'

为了转义单引号，我尝试添加这样的反冲-

In order to escape the single quote, I tried appending a backlash like this -

[variable1]=='Sample\'s Data'

但是当将其分配给字符串变量时，它会将反斜杠删除为-

But when this is assigned to a string variable, it removes the backslash as -

[variable1]=='Sample's Data'

，并将其分配给Expression构造函数后，当评估出第二个单引号"s Data"之后的文本未被识别时，它将引发错误.

and after assigning this to the Expression constructor, it throws an error when evaluated that text after the second single quote "s Data" is not recognized.

当我尝试如下添加两个反斜杠时-

When I try appending two backslashes as below -

[variable1]=='Sample\\'s Data'，

这被分配给一个字符串变量，

this is assigned to a string variable as

"[variable1]=='Sample\'s Data'"

但是评估它不会抛出异常，但是由于数据是正确的，所以比较失败

but evaluating it doesn't throw the exception but fails the comparison since the data is

"[variable1]=='Sample's Data'"

没有反斜杠.

我该如何解决?

推荐答案

一种可能的方法是对'使用Unicode代码点，即

A possible way is to use the Unicode code point for ' which is U+0027

var e = new Expression(@"'Sample\u0027s Data'");
var evaluated = e.Evaluate();

来源

或者简单地:

var e = new Expression(@"'Sample\'s Data'");
var evaluated = e.Evaluate();

没有逐字字符串:

var e = new Expression("'Sample\\'s Data'");
var evaluated = e.Evaluate();

这给出了true:

var e = new Expression("variable=='Sample\\'s Data'");
e.Parameters["variable"] = "Sample's Data";
var evaluated = e.Evaluate();

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