C#判断文件是否存在的常用方法

using System.IO;

string filePath = @"C:\example\test.txt";

if (File.Exists(filePath))
{
    Console.WriteLine("文件存在");
}
else
{
    Console.WriteLine("文件不存在");
}

using System.IO;

string filePath = @"C:\example\test.txt";
FileInfo fileInfo = new FileInfo(filePath);

if (fileInfo.Exists)
{
    Console.WriteLine("文件存在");
    Console.WriteLine($"文件大小: {fileInfo.Length} 字节");
}
else
{
    Console.WriteLine("文件不存在");
}

using System.IO;

string filePath = @"C:\example\test.txt";

try
{
    using (FileStream fs = File.OpenRead(filePath))
    {
        Console.WriteLine("文件存在且可访问");
    }
}
catch (FileNotFoundException)
{
    Console.WriteLine("文件不存在");
}
catch (DirectoryNotFoundException)
{
    Console.WriteLine("目录不存在");
}
catch (IOException ex)
{
    Console.WriteLine($"IO错误: {ex.Message}");
}

using System.IO;
using System.Threading.Tasks;

async Task<bool> FileExistsAsync(string path)
{
    return await Task.Run(() => File.Exists(path));
}

// 使用示例
string filePath = @"C:\example\test.txt";
bool exists = await FileExistsAsync(filePath);
Console.WriteLine(exists ? "存在" : "不存在");

public static bool SafeFileExists(string path)
{
    try
    {
        // 检查路径是否合法
        if (string.IsNullOrWhiteSpace(path)) 
            return false;
            
        // 移除路径两端的引号（如果有）
        path = path.Trim().Trim('"');
        
        // 检查根路径格式
        if (path.StartsWith(@"\\")) // UNC路径
            return Directory.Exists(Path.GetDirectoryName(path)) && File.Exists(path);
        
        // 普通路径
        string root = Path.GetPathRoot(path);
        if (!Directory.Exists(root)) 
            return false;
            
        return File.Exists(path);
    }
    catch (Exception ex) when (
        ex is ArgumentException || 
        ex is PathTooLongException ||
        ex is NotSupportedException)
    {
        // 处理无效路径异常
        return false;
    }
}