以下是一些示例： c＃ - 您可以调用Directory.GetFiles （）有多个过滤器？ - 堆栈溢出 [ ^ ]

如果我理解你，你想在文件夹中找到丢失的文件（日期）。



这是一个Linq解决方案：

  //  定义初始文件夹和扩展名 
 string  initialdir =  @  C：\myfiles跨度>; 
 string  fileExt =   * .xlsx 跨度>; 
 //  从文件名中提取日期所需 
 System.Globalization.CultureInfo cu = System.Globalization.CultureInfo.InvariantCulture; 

 //  获取文件和缺少日期 
 var  filesAndDates = Directory.EnumerateFiles（initialdir，fileExt，SearchOption.AllDirectories）
 //  按目录名称分组文件 
 .GroupBy（x = >  Path.GetDirectoryName（x））
 //  从文件名中选择文件和相应日期 
。选择（grp = >   new  
 {
 folder = grp.Key，
 files = grp.Select（f => Path.GetFileNameWithoutExtension（f））。ToList（），
 dates = grp.Select（f => DateTime.ParseExact（Path.GetFileNameWithoutExtension（f）.Replace（  myfile _， ），  ddMMyyyy，cu））。ToList（），
}）
 //  在文件夹中查找缺少日期 
 .SelectMany（x = >  
 //  在当前文件夹中创建最小值和最大值之间的日期范围 - 获取所有日期 
 //  排除已存在的日期 
 Enumerable.Range（ 0  ，（ int ）（x.dates.Max（） -  x.dates.Min（））。TotalDays +  1 ）
。选择（i = >  x.dates.Min（）。AddDays（i））
。除外（x .dates）
。选择（y = >   new  
 {
 folder = x.folder，
 missingDate = y 
}）
）; 

 foreach （ var  fd  in  filesAndDates）
 {
 Console.WriteLine（  {0} \ t | \t {1}，fd.folder，fd.missingDate.ToString（  yyyy -MM-dd，cu））; 
} 

结果：

 C：\ myfiles\files1 | 2017-05-19 
 C：\ myfiles\files2 | 2017-05-23 

如果您想知道它的工作原理，请阅读上面代码中的评论。

I require a to check whether a file named with a particular pattern exist inside a directory or not through C# code.
Say my directory is

c:\myfiles\files1

. This directory is having some excel files named in the following pattern.

myfile_17052017
myfile1_18052017.xlsx
myfile1_20052017.xlsx
myfile1_21052017.xlsx
myfile1_22052017.xlsx
myfile1_23052017.xlsx
myfile1_24052017.xlsx

and

C:\myfiles\files2

<pre>myfile_17052017
myfile2_18052017.xlsx
myfile2_19052017.xlsx
myfile2_20052017.xlsx
myfile2_21052017.xlsx
myfile2_22052017.xlsx
myfile2_24052017.xlsx

and
so on..........

These files are generated by some other application in

c:\myfiles\files1,c:\myfiles\files2,c:\myfiles\files3 and so on. . .

directory.
Here you can notice that file of date

19052017

is missing inside

c:\myfiles\files1\

directory and file of

23052017

is missing inside

c:\myfiles\files2\

directory.I need to check which files are missing and store the names of the missing files with their respective directory name in a .txt file in the file pattern shown above.
I have multiple directories like files1,files2.files3 ,files4 etc.. inside

c:\myfiles\

directory stated as above.

So I need to run this check through out all the sub directories inside

c:\myfiles\

directory.

Can I have some example of C# for this requirement?

What I have tried:

I am a begineer in C# and need some example of cod eby which I can achieve the goal.

Here are some examples: c# - Can you call Directory.GetFiles() with multiple filters? - Stack Overflow[^]

If i understand you well, you want to find missing files (dates) in folders.

Here's a Linq solution:

//define initial folder and extension
string initialdir = @"C:\myfiles";
string fileExt = "*.xlsx";
//needed to extract date from file name
System.Globalization.CultureInfo cu = System.Globalization.CultureInfo.InvariantCulture;

//get files and missing dates
var filesAndDates = Directory.EnumerateFiles(initialdir, fileExt, SearchOption.AllDirectories)
    //group files by directory name
    .GroupBy(x => Path.GetDirectoryName(x))
    //select files and corresponding dates from file name
    .Select(grp => new
        {
            folder = grp.Key,
            files = grp.Select(f=>Path.GetFileNameWithoutExtension(f)).ToList(),
            dates = grp.Select(f=>DateTime.ParseExact(Path.GetFileNameWithoutExtension(f).Replace("myfile_", ""), "ddMMyyyy", cu)).ToList(),
        })
    //find missing dates in folders
    .SelectMany(x =>
        //create date range between min and max in current folder - get all dates
        //exclude dates which already exist
        Enumerable.Range(0, (int)(x.dates.Max() - x.dates.Min()).TotalDays + 1)
            .Select(i => x.dates.Min().AddDays(i))
            .Except(x.dates)
            .Select(y=> new
                {
                    folder = x.folder,
                    missingDate = y
                })
        );

foreach(var fd in filesAndDates)
{
    Console.WriteLine("{0}\t|\t{1}", fd.folder, fd.missingDate.ToString("yyyy-MM-dd", cu));
}

Result:

C:\myfiles\files1  |  2017-05-19
C:\myfiles\files2  |  2017-05-23

If you would like to know how it works, please read my comments in the code above.