问C# DirectoryNotFoundException在Windows 10机器中未被处理

EN

using System;
using System.Windows.Forms;
using System.IO;

namespace WindowsFormsApplication2
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        string fullComputerName = Environment.MachineName;

        //Create a Folder Path
        string createFolderPath = @"C:\\Users\\" +fullComputerName+"\\Documents\\Cheques";

        //Create a File Inside of a Folder
        string createTxtFile= createFolderPath + "\\ChequeForDeposit.TXT";

        try
        {
            if(!Directory.Exists(createFolderPath))
            { return; }
            Directory.CreateDirectory(createFolderPath);
        }
        catch { }
        finally { }

        if(!File.Exists(createTxtFile))
        { File.Create(createTxtFile); }//The error is here
    }
}
}