Santiago's helpful answer的另一种方法，也依赖于为每个匹配调用的匹配评估器脚本块：
总的想法是：

• 循环遍历匹配文本和替换文本共享的所有字符
• 使用System.Text.StringBuilder示例逐字符构建替换文本的大小写匹配版本。
• 替换字符串中的任何其他字符（在匹配文本中没有对应字符的字符）将按原样保留。

两种解决方案均低于预期输出<XyZ>。
PowerShell (Core) 7+解决方案：

# Sample input string
$inputString = '<UvW>'
# Sample search pattern.
$searchPattern = 'uvw'
# Sample replacement text.
$replaceWith = 'xyz'

# A string builder to make constructing the case-matched replacement string
# more efficient.
$caseMatchedReplaceWith = [System.Text.StringBuilder]::new($replaceWith.Length)

$inputString -replace $searchPattern, {  
  $matchedText = $_.Value
  $numCharsToMatch = [Math]::Min($replaceWith.Length, $matchedText.Length)
  $null = $caseMatchedReplaceWith.Clear()
  foreach ($i in 0..($numCharsToMatch-1)) {
    $replacementChar = $replaceWith[$i]
    if ([char]::IsUpper($matchedText[$i]) -and -not [char]::IsUpper($replacementChar)) {
      $replacementChar = [char]::ToUpper($replacementChar)
    } 
    $null = $caseMatchedReplaceWith.Append($replacementChar)
  }
  $caseMatchedReplaceWith.ToString() + $replaceWith.Substring($numCharsToMatch)
}

• Windows PowerShell* 解决方案（不支持使用脚本块作为-replace的替换操作数）：

# Sample input string
$inputString = '<UvW>'
# Sample search pattern.
$searchPattern = 'uvw'
# Sample replacement text.
$replaceWith = 'xyz'

# A string builder to make constructing the case-matched replacement string
# more efficient.
$caseMatchedReplaceWith = [System.Text.StringBuilder]::new($replaceWith.Length)

[regex]::Replace(
  $inputString,
  $searchPattern, 
  {  
    $matchedText = $args[0].Value
    $numCharsToMatch = [Math]::Min($replaceWith.Length, $matchedText.Length)
    $null = $caseMatchedReplaceWith.Clear()
    foreach ($i in 0..($numCharsToMatch-1)) {
      $replacementChar = $replaceWith[$i]
      if ([char]::IsUpper($matchedText[$i]) -and -not [char]::IsUpper($replacementChar)) {
        $replacementChar = [char]::ToUpper($replacementChar)
      } 
      $null = $caseMatchedReplaceWith.Append($replacementChar)
    }
    $caseMatchedReplaceWith.ToString() + $replaceWith.Substring($numCharsToMatch)
  },
  'IgnoreCase'
)

所以，这是令人难以置信的低效，但我没有看到一种方法，你需要使用一个匹配评估器和一个哈希表来Map匹配的字符与它们的替换字符。
代码看起来会有所不同，这取决于您是在PowerShell 7+上使用脚本块进行替换，还是在Windows PowerShell 5.1上使用脚本块进行替换，在Windows PowerShell 5.1上您需要调用Regex.Replace API来定位MatchEvaluator重载之一。

• PowerShell 7+

$evaluator = {
    # enumerate each character from the matched value
    # `.Value` in this context from the examples would be `uvw`, `UVW` and `Uvw`
    $result = foreach ($char in $_.Value.GetEnumerator()) {
        # here we get the replacement character
        # i.e.:
        #  - if `$char` is `u` then `$value` is `x`
        #  - if `$char` is `v` then `$value` is `y`
        $value = $map[$char.ToString()]
        # check if the enumerated character is uppercase
        if ([char]::IsUpper($char)) {
            # then, we need to output the uppercase replacement char too
            $value.ToUpper()
            # and go to the next char
            continue
        }
        
        # else, just output the char as-is (lowercase)
        $value
    }

    # lastly, after all matched characters are processed,
    # create a new string from the char array
    [string]::new($result)
}

$map = @{
    u = 'x'
    v = 'y'
    w = 'z'
}

'foo uvw bar' -replace 'uvw', $evaluator # Outputs: foo xyz bar
'foo UVW bar' -replace 'uvw', $evaluator # Outputs: foo XYZ bar
'foo Uvw bar' -replace 'uvw', $evaluator # Outputs: foo Xyz bar

• Windows PowerShell 5.1：

$evaluator = {
    $result = foreach ($char in $args[0].Value.GetEnumerator()) {
        $value = $map[$char.ToString()]
        if ([char]::IsUpper($char)) {
            $value.ToUpper()
            continue
        }

        $value
    }

    [string]::new($result)
}

$map = @{
    u = 'x'
    v = 'y'
    w = 'z'
}

$re = [regex]::new('uvw', [System.Text.RegularExpressions.RegexOptions]::IgnoreCase)
$re.Replace('foo uvw bar', $evaluator) # Outputs: foo xyz bar
$re.Replace('foo UVW bar', $evaluator) # Outputs: foo XYZ bar
$re.Replace('foo Uvw bar', $evaluator) # Outputs: foo Xyz bar