Question

有我想在LINQ Expression中获取文件名（我不确定是否可以这样问）

请查看代码，找到“这里如何在DB中获取文件名”

public static IEnumerable<string> GetFiles(List<string> srcFiles)
{
    var filePaths = new List<string>();
    using (var db = new ContentMgmtContext())
    {
        foreach (var fileInfo in srcFiles.Select(file => new FileInfo(file)))
        {
            if (db.Files.Any(o => o.FileName.ToLower() == fileInfo.Name.ToLower() || o.FileSize == fileInfo.Length.ToString())) 
            {
                Console.WriteLine("{0} already exist in DB", fileInfo.Name);
                Console.WriteLine("Conflict file in DB is: {0}",HERE HOW TO GET THE FILE'S NAME IN DB???);
            }
            else
            {
                filePaths.Add(fileInfo.FullName);
            }
        }
    }
    return filePaths;
}

Answer 1

您可以尝试收集符合条件的每个数据库条目

public static IEnumerable<string> GetFiles(List<string> srcFiles)
{
    var filePaths = new List<string>();
    using (var db = new ContentMgmtContext())
    {
        foreach (var fileInfo in srcFiles.Select(file => new FileInfo(file)))
        {
            var matches = db.Files.Where(o => o.FileName.ToLower() == fileInfo.Name.ToLower() ||
                o.FileSize == fileInfo.Length.ToString())

            if (matches.Count() > 0)
            {
                foreach (var match in matches)
                {
                    Console.WriteLine("{0} already exist in DB", fileInfo.Name);
                    Console.WriteLine("Conflict file in DB is: {0}",match.FileName);
                }
            }
            else
            {
                filePaths.Add(fileInfo.FullName);
            }
        }
    }
    return filePaths;
}

Answer 2

要保留数据库中的匹配对象，您需要使用返回匹配项的内容替换Any运算符。例如

var match = db.Files.FirstOrDefault(o 
            => o.FileName.ToLower() == fileInfo.Name.ToLower() 
                || o.FileSize == fileInfo.Length.ToString());
if (match != null) {
  // Found...
}

在LINQ表达式中获取对象

2 个答案: