Parse a CSV file with PowerShell in C#

ParseCsv.cs

using (var shell = PowerShell.Create(sessionState))
{
    var parameters = new Dictionary<string, object>
                         {
                             {"Path", tempFilePath},
                             {"Delimiter", ','}
                         };

    var command = shell.AddCommand("Import-Csv").AddParameters(parameters);
    var results = command.Invoke();

    foreach (dynamic result in results)
    {
        environment.LastReleaseDate = result.ReleaseDate;
        environment.PreviousBuild = result.PreviousVersion;
        environment.CurrentBuild = result.CurrentVersion;
    }
}

Another approach. Leveraging positional parameters for the Import-Csv cmdlet. Your approach does provide more control over what PowerShell executes. With this approach, tempFilePath can have arbitrary PS code injected.

            var script = string.Format("Import-Csv " + tempFilePath);

            var ps = PowerShell.Create().AddScript(script);

            foreach (dynamic item in ps.Invoke())
            {

                Console.WriteLine(new Details()
                {
                    ReleaseDate = item.ReleaseDate,
                    PreviousVersion = item.PreviousVersion,
                    CurrentVersion = item.CurrentVersion
                });
            }