How to Check if a Process has a Lock on a File

This example illustrates an efficient way to check for file locks using a simple extension method.

File locks caused by open processes are a common source of error when trying to perform I/O operations on a file. This example illustrates an efficient way to check for file locks using a simple extension method.

Step 1: Create an extension method on the FileInfo class:

public static bool IsLocked(this FileInfo f)
{
    try
    {
        string fpath = f.FullName;
        FileStream fs = File.OpenWrite(fpath);
        fs.Close();
        return false;
    }

    catch (Exception) { return true; }
}

Step 2: Create a reference to the file and check it before performing your operation:

FileInfo fi = new FileInfo(@"C:\4067918.TIF");
if (!fi.IsLocked()) { //DO SOMETHING HERE ;}