系统方法，判断文件是否打开并可选择关闭

Falcon.SugarApi.Windows/FileExtend.cs

@@ -0,0 +1,36 @@
+using System.Runtime.InteropServices;
+
+namespace Falcon.SugarApi.Windows
+{
+    /// <summary>
+    /// 文件操作扩展
+    /// </summary>
+    public static class FileExtend
+    {
+        [DllImport("kernel32.dll")]
+        private static extern IntPtr _lopen(string lpPathName,int iReadWrite);
+
+        [DllImport("kernel32.dll")]
+        private static extern bool CloseHandle(IntPtr hObject);
+
+        /// <summary>
+        /// 判断文件是否打开，并可选是否关闭
+        /// </summary>
+        /// <param name="path">文件路径</param>
+        /// <param name="close">True关闭文件，不关闭。默认不关闭</param>
+        /// <returns>True文件打开，False文件没有打开</returns>
+        public static bool IsOpen(this string path,bool close = false) {
+            if(!File.Exists(path)) {
+                return false;
+            }
+            var handle = _lopen(path,2|0x40);
+            if(handle==new IntPtr(-1)) {
+                return true;
+            }
+            if(close) {
+                CloseHandle(handle);
+            }
+            return false;
+        }
+    }
+}