Csharp 在FilePath中搜索一个词，并根据First Match从左到右提取文件路径

我正在努力extract the path from left to right based on the first match from left to right but only with the Folder name and not with the file name:

string numberToFind = "99999";

string filePath = "\\mydomain.com\TestEnv\MyApp\ImportantFiles\Phase 1\Employee\Folder 1\Folder 1.2\Folder 1.2.1_99999_PayRoll data\Folder 99999\JanSlip.pdf";

int resultIndex = data.LastIndexOf(numberToFind);
if(resultIndex!=-1)
{
   data = data.Substring(0,resultIndex);
}
Output - \\mydomain.com\TestEnv\MyApp\ImportantFiles\Phase 1\Employee\Folder 1\Folder 1.2\Folder 1.2.1_

Expected Output :

"\mydomain.com\TestEnv\MyApp\ImportantFiles\Phase 1\Employee\文件夹 1\Folder1.2\文件夹1.2.1_99999_Payroll Data

如你所见，我得到的输出与‘预期输出’不匹配.

请注意，我只想match the numberToFind on the folder level并根据第一个匹配项从左到右提取路径，但如果在文件夹级别上没有找到匹配项，我想返回整个路径.For eg:

string numberToFind = "99999";
    
string filePath = "\\mydomain.com\TestEnv\MyApp\ImportantFiles\Phase 1\Employee\Folder 1\Folder 1.2\99999_JunePayslips.pdf";

Expected output : \\mydomain.com\TestEnv\MyApp\ImportantFiles\Phase 1\Employee\Folder 1\Folder 1.2\99999_JunePayslips.pdf