I have a program that will check if .csv file is created. If created, do something, if not wait untill its created. Is it possible in C#?

Tried something like this but didn't work well...

        var startTimeSpan = TimeSpan.Zero;
        var periodTimeSpan = TimeSpan.FromMinutes(1);

        var timer = new System.Threading.Timer((e) =>
        {
            if (!File.Exists(@"TestFileLocation"))
        {
            MethodName(); //Tried this to start method agian
        }
        else
        {
            HereIsRestOfTheCodeToDoSomeActions();
        }
        }, null, startTimeSpan, periodTimeSpan);

If my post isn't clear enough, sorry I'm not fluent in English, below are steps, how program will work:

1. Check if file is created in folder
2. If not, wait 1 minute and check again
3. If file is created do some things
4. Loop this steps from start

CodePudding user response：

The perfect fit for your problem would be to use a FileSystemWatcher. Its job is to watch a directory for changes such as the creation of files as you need it in your problem.

That would also make the one-minute-threshold obsolete. Consider for example:

// necessary assembly using for using FileSystemWatcher classes.
using System.IO;

// ...

// instantiate your watcher.
using var watcher = new FileSystemWatcher(@"C:\path\to\folder");

// just filter for interesting attribtes.
watcher.NotifyFilter = NotifyFilters.FileName;

// attach an event handler to the event that is triggered when a file is created.
watcher.Created  = OnCreated;

// ...

// implement the event handler.
private static void OnCreated(object sender, FileSystemEventArgs e)
{
    // if the name is "your" name, you're ready to go ...
    if (e.Name == "my_name")
        // do something ...

}

However, if you still want to use a loop (due to constraints you didn't state in your post), then it might probably be something like the following less adorable approach:

var now = DateTime.Now;
var waitTime = TimeSpan.FromMinutes(1);
    
while (true)
{
    if (!File.Exists(@"TestFileLocation"))
    {
        // do something ...
            
        // exit the loop.
        break;
    }
        
    Thread.Sleep(waitTime);
}

Note and take care that this endless-loop blocks the main thread until you found your file. A better approach would be to execute that task in a separate thread aside from the main thread.

CodePudding user response：

Create FileSystemWatcher https://docs.microsoft.com/en-us/dotnet/api/system.io.filesystemwatcher?view=net-6.0 and add check in OnCreated