c# - C#处理文件错误

Question

我正在尝试打开文件，并且想返回例如如果文件路径不存在，则为X；如果无法打开文件，则为Y；如果成功，则为Z。
但是，我不明白如何检查“文件无法打开”错误，并且目前尚不确定我的try-catch是否正确。我还想添加另一条语句来检查文件是否已经打开。

public int Opener(string fileName)
    { 
    string text = "";
        
        try
        {
            text = File.ReadAllText(fileName);
            return "Something to Return";
        }
        catch (FileNotFoundException)
        {
            return "Something to Return";
        }

Answer 1

您可以使用它来检查您描述的情况:

try
{
    string text = File.ReadAllText(fileName);

    //Z: reading was successful
}
catch (Exception ex)
{
    if (ex.InnerException is IOException)
    {
        //Y: file is already being read
    }
    else if (ex.InnerException is FileNotFoundException)
    {
        //X: file does not exist
    }
}