在 C# 中替换文本，同时保持大小写不变

我有一组句子需要用来进行替换，例如：

abc => cde
ab df => de
...

我有一个文本可以在哪里进行更改。 但是我无法事先知道所述文本的大小写。 因此，举例来说，如果我有：

A bgt abc hyi. Abc Ab df h

我必须更换并获得：

A bgt cde nyi. Cde De h

或者尽可能接近，即保持大小写

EDIT:由于我看到对此有很多困惑，我将尝试澄清一下：

我问的是一种在更换后保留大写字母的方法，我认为这种方法没有很好地通过（没有很好地解释这意味着什么），所以我将使用真实的单词给出一个更现实的例子。

把它想象成一个词汇表，用它们的同义词替换表达式，可以这么说，所以如果我映射：

didn't achieve success => failled miserably

然后我得到作为输入的句子：

As he didn't achieve success, he was fired

我会得到

As he failled miserably, he was fired

但如果没有大写，那么就会失败，如果成就或成功大写，那么就会很糟糕，如果有超过 1 个字母大写，那么它的对应部分也会大写

我的主要可能性是（我真正想考虑的）

• 仅第一个单词的第一个字母大写
• 仅每个单词的第一个字母大写
• 所有字母均大写

如果我能处理这三个，我想这已经是可以接受的了 - 这是更容易的 - 当然，如果有的话，更深入的解决方案会更好

有任何想法吗？

不确定这会有多好，但这就是我想出的：

        string input = "A bgt abc hyi. Abc Ab df h";
        Dictionary<string, string> map = new Dictionary<string, string>();
        map.Add("abc", "cde");
        map.Add("ab df", "de");

        string temp = input;
        foreach (var entry in map)
        {
            string key = entry.Key;
            string value = entry.Value;
            temp = Regex.Replace(temp, key, match =>
            {
                bool isUpper = char.IsUpper(match.Value[0]);

                char[] result = value.ToCharArray();
                result[0] = isUpper
                    ? char.ToUpper(result[0])
                    : char.ToLower(result[0]);
                return new string(result);
            }, RegexOptions.IgnoreCase);
        }
        label1.Text = temp; // output is A bgt cde hyi. Cde De h

EDIT阅读修改后的问题后，这是我修改后的代码（事实证明，步骤与@Sephalia的代码类似......以及类似的变量名称 lol ）

现在的代码有点复杂..但我认为还可以

        string input = 
        @"As he didn't achieve success, he was fired.
        As he DIDN'T ACHIEVE SUCCESS, he was fired.
        As he Didn't Achieve Success, he was fired.
        As he Didn't achieve success, he was fired.";
        Dictionary<string, string> map = new Dictionary<string, string>();
        map.Add("didn't achieve success", "failed miserably");


        string temp = input;
        foreach (var entry in map)
        {
            string key = entry.Key;
            string value = entry.Value;
            temp = Regex.Replace(temp, key, match =>
            {
                bool isFirstUpper, isEachUpper, isAllUpper;

                string sentence = match.Value;
                char[] sentenceArray = sentence.ToCharArray();

                string[] words = sentence.Split(' ');

                isFirstUpper = char.IsUpper(sentenceArray[0]);

                isEachUpper = words.All(w => char.IsUpper(w[0]) || !char.IsLetter(w[0]));

                isAllUpper = sentenceArray.All(c => char.IsUpper(c) || !char.IsLetter(c));

                if (isAllUpper)
                    return value.ToUpper();

                if (isEachUpper)
                {
                    // capitalize first of each word... use regex again :P
                    string capitalized = Regex.Replace(value, @"\b\w", charMatch => charMatch.Value.ToUpper());
                    return capitalized;
                }


                char[] result = value.ToCharArray();
                result[0] = isFirstUpper
                    ? char.ToUpper(result[0])
                    : char.ToLower(result[0]);
                return new string(result);
            }, RegexOptions.IgnoreCase);
        }
        textBox1.Text = temp; 
        /* output is :
        As he failed miserably, he was fired.
        As he FAILED MISERABLY, he was fired.
        As he Failed Miserably, he was fired.
        As he Failed miserably, he was fired.
        */