第一种方法: using System.IO; using System.Runtime.InteropServices; [DllImport("kernel32.dll")] public static extern IntPtr _lopen(string lpPathName, int iReadWrite); [DllImport("kernel32.dll")] public static extern bool CloseHandle(IntPtr hObject); public const int OF_READWRITE = 2; public const int OF_SHARE_DENY_NONE = 0x40; public readonly IntPtr HFILE_ERROR = new IntPtr(-1); private void button1_Click(object sender, EventArgs e) { string vFileName = @"c: emp emp.bmp"; if (!File.Exists(vFileName)) { MessageBox.Show("文件都不存在!"); return; } IntPtr vHandle = _lopen(vFileName, OF_READWRITE | OF_SHARE_DENY_NONE); if (vHandle == HFILE_ERROR) { MessageBox.Show("文件被占用!"); return; } CloseHandle(vHandle); MessageBox.Show("没有被占用!"); } 第二种方法: public static bool IsFileInUse(string fileName) { bool inUse = true; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.None); inUse = false; } catch { } finally { if (fs != null) fs.Close(); } return inUse;//true表示正在使用,false没有使用 }