Catch Commandline error

I am trying to catch an error with an incorrect commandline parameter for the application of form

Myapp.exe myFile.txt

The application however throws an "Unhandled exception - The path is not of legal form".

Below is my code and I am wondering why it does not show the message box as provided in the code? Thanks.

String[] cmdlineArgs = Environment.GetCommandLineArgs();

if (cmdlineArgs.Length == 2)
{
    try
    {
        if (File.Exists(cmdlineArgs[1].ToString()))
            ConfigPar开发者_开发技巧ameters.SetConfigParameters(cmdlineArgs[1].ToString());
        else
            {
                MessageBox.Show("Configuration file does not exist.Restarting...");
                Environment.Exit(1);
             }
     }
     catch (Exception ex)
     {

     }

If you pass an invalid path to File.Exists (such, C:\D:/E:\), you get that exception.

Check for improper characters in the file path (e.g. '>' <'>, etc...).

http://msdn.microsoft.com/en-us/library/system.io.path.getinvalidfilenamechars.aspx & http://msdn.microsoft.com/en-us/library/system.io.path.getinvalidpathchars.aspx

You should modify your code like bellow is more better :D

String[] cmdlineArgs = Environment.GetCommandLineArgs();

if (cmdlineArgs.Length == 2)
{
    try
    {
        if (File.Exists(cmdlineArgs[1].ToString()))
            ConfigParameters.SetConfigParameters(cmdlineArgs[1].ToString());
     }
     catch (Exception ex)
     {
          MessageBox.Show("Configuration file does not exist.Restarting...");
          Environment.Exit(1);
     }
}

Because when your file path contain some special characters(<, >, ?, *, etc), the File.Exists() maybe throw exception as you see.