文件流异常在范围内获取try和catch块时遇到问题

Question

如果键入了错误的文件名但是似乎无法使用try catch块保留所有内容，我想在此类中处理FileNotFoundException。请指点

此处抛出异常（FileStream fileStream = File.OpenRead（fileName））

public class XcelReader
{
    private readonly List<List<IRule>> m_Rules;

    public XcelReader(List<List<IRule>> rules)
    {
        m_Rules = rules;
    }

    public void ValidateWorksheet(string fileName)
    {
        bool allRulesPassed = true;

        WorkbookProvider workbookProvider = new WorkbookProvider();

        int counter = 0;
        IWorkbook workbook;

        using (FileStream fileStream = File.OpenRead(fileName))
            workbook = workbookProvider.GetWorkbook(fileStream, SpreadsheetType.Xlsx);

        for (int rowCounter = 1; rowCounter < workbook.Worksheets[1].Rows.Count; rowCounter++)
        {
            IRow row = workbook.Worksheets[1].Rows[rowCounter];

            for (int columnCounter = +1; columnCounter < row.Cells.Count; columnCounter++)
            {
                List<string> failedRules = ColumnValueIsValid(row.Cells[columnCounter].Value, m_Rules[columnCounter]);

                failedRules.ForEach(failedRule =>
                {

                    allRulesPassed = false;
                    Console.WriteLine("\n[{0}:{1}] Failed: {2}", rowCounter +1, GetColumnHeaderValue(columnCounter + 1), failedRule);
                    counter++;

                    if (counter > 20)
                    {
                        Console.WriteLine("\nHit enter to page down................");
                        Console.ReadLine();
                        counter = 0;
                    }

                });
            }
        }

        if(allRulesPassed)
            Console.WriteLine(@"WOOHOO! worksheet is hunky dory Hit enter to continue");
    }

    private string GetColumnHeaderValue(int columnCounter)
    {

       return new Base26Converter().FromBase10(columnCounter);
    }

    private List<string> ColumnValueIsValid(string value, List<IRule> rules)
    {
        List<string> failedRules = new List<string>();

         rules.ForEach(rule =>
         {
             if(!rule.IsValid(value))
                 failedRules.Add(rule.GetReasonForFailure(value));
         });

        return failedRules;
    }
}