string.Replace(或其他字符串修改)不起作用 [英] string.Replace (or other string modification) not working

问题描述

对于以下代码，我无法让 string.Replace 工作:

For the following code, I can't get the string.Replace to work:

someTestString.Replace(someID.ToString(), sessionID);

当我调试和检查参数时，它们有我期望的值 - 即 someID.ToString() 得到1087163075"，而 sessionID 有108716308"和 someTestString 包含1087163075".

when I debug and check parameters they have values I expect - i.e. someID.ToString() got "1087163075", and sessionID has "108716308" and someTestString contains "1087163075".

我不知道为什么这不起作用更改 someTestString

完整示例:

string someTestString = 
      "<a href='myfoldert/108716305-1.jpg' target='_blank'>108716305-1.jpg</a>"
someTestString.Replace("108716305", "NewId42");  

结果(在 someTestString 中)应该是这样的:

the result (in someTestString) should be this:

"<a href='myfoldert/NewId42-1.jpg' target='_blank'>NewId42-1.jpg</a>" 

但它没有改变.在点击我的代码后，someTestString 的字符串保持不变.

but it doesn't change. The string for someTestString remains unchanged after hitting my code.

推荐答案

字符串是不可变的.string.Replace 的结果是一个带有替换值的新字符串.

Strings are immutable. The result of string.Replace is a new string with the replaced value.

您可以将结果存储在新变量中:

You can either store result in new variable:

var newString = someTestString.Replace(someID.ToString(), sessionID);

或者如果您只想观察字符串更新"行为，则只需重新分配给原始变量:

or just reassign to original variable if you just want observe "string updated" behavior:

someTestString = someTestString.Replace(someID.ToString(), sessionID);

请注意，这适用于所有其他 string 函数，例如 Remove、Insert、trim 和 substring 变体 - 它们都返回新字符串作为不能修改原始字符串.

Note that this applies to all other string functions like Remove, Insert, trim and substring variants - all of them return new string as original string can't be modified.

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