C# 从目录中选择随机文件
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select random file from directory
提问by Crash893
I've seen a few examples but none so far in C#, what is the best way to select a random file under a directory?
我在 C# 中看过一些例子，但到目前为止还没有，在目录下选择随机文件的最佳方法是什么？
In this particular case I want to select a wallpaper from "C:\wallpapers" every 15 or so minutes.
在这种特殊情况下，我想每 15 分钟左右从“C:\wallpapers”中选择一张壁纸。
Thanks.
谢谢。
采纳答案by Crash893
select random file from directory
private string getrandomfile2(string path)
{
string file = null;
if (!string.IsNullOrEmpty(path))
{
var extensions = new string[] { ".png", ".jpg", ".gif" };
try
{
var di = new DirectoryInfo(path);
var rgFiles = di.GetFiles("*.*").Where( f => extensions.Contains( f.Extension.ToLower()));
Random R = new Random();
file = rgFiles.ElementAt(R.Next(0,rgFiles.Count())).FullName;
}
// probably should only catch specific exceptions
// throwable by the above methods.
catch {}
}
return file;
}
回答by Mouk
Get all files in an array and then retrieve one randomly
获取数组中的所有文件，然后随机检索一个
var rand = new Random();
var files = Directory.GetFiles("c:\wallpapers","*.jpg");
return files[rand.Next(files.Length)];
回答by leora
why not just:
为什么不只是：
- get the files into an array
- use the Random class to select a number that is random between 0 and files.Length
- Grab the file from the array using the random number as the index
- 将文件放入数组
- 使用 Random 类选择一个在 0 和 files.Length 之间随机的数字
- 使用随机数作为索引从数组中获取文件
回答by Lance Harper
var files = new DirectoryInfo(@"C:\dev").GetFiles();
int index = new Random().Next(0, files.Length);
Console.WriteLine(files[index].Name);
回答by Daniel A. White
Use the Directory.GetFiles(...)to get the array of filenames and use the Randomclass to select a random file.
使用Directory.GetFiles(...)获取文件名数组并使用Random类选择随机文件。
回答by Jason Cohen
If you're doing this for wallpapers, you don't want to just select a file at random because it won't appear random to the user.
如果您要为壁纸执行此操作，您不想只是随机选择一个文件，因为它不会对用户显示随机。
What if you pick the same one three times in a row? Or alternate between two?
如果你连续三次选择同一个怎么办？还是两者交替？
That's "random," but users don't like it.
这是“随机的”，但用户不喜欢它。
See this post about how to display random pictures in a way users will like.
请参阅这篇关于如何以用户喜欢的方式显示随机图片的帖子。
回答by Nick Kovalsky
Just my 5 cents, code for an mvc action, using cookies so we do not repeat the same filename twice:
只是我的 5 美分，用于 mvc 操作的代码，使用 cookie，因此我们不会重复相同的文件名两次：
[AllowAnonymous]
//-------------------------------------------------------------
public async Task<ActionResult> RandomBackground()
//-------------------------------------------------------------
{
var basePath = "~/Content/images/backgrounds";
var dir = System.Web.Hosting.HostingEnvironment.MapPath(basePath);
var rand = new Random();
var files = System.IO.Directory.GetFiles(dir, "*.jpg");
if (files!=null)
{
var cookie = "Background";
var pickedFile = "";
var fileName = "";
var oldFilename = "";
while ((oldFilename == fileName) && files.Count<string>()>1)
{
oldFilename = ReadControllerCookie(cookie);
pickedFile = files[rand.Next(files.Length)];
fileName = System.IO.Path.GetFileName(pickedFile);
}
SaveControllerCookie(cookie, fileName);
return Content(fileName);
}
return new EmptyResult();
}
Used as:
用作：
<img src="~/Content/images/backgrounds/@Html.Action("RandomBackground", "YourControllerName")">
