Try
private void Button_Click(object sender, RoutedEventArgs e)
{
string filename = "Netflix_run.bat";
string parameters = $"/k \"{filename}\"";
Process.Start("cmd", parameters);
}
Explanation:
In your code, you did not put
Netflix_run.bat between double quotes. I'm surpised this would compile, unless you define a Netflix_run class having a string property named bat.
Moreover, .bat files are not executable files which can be launched directly. You have to use the command processor (cmd.exe) to execute a shell script.
The line
string parameters = $"/k \"{filename}\"";
is building the string
/k "Netflix_run.bat"