方案：

首先，您必须知道在复制或替换数据库文件之前，您必须将数据库设置为脱机状态，并在完成后将其重新联机。

上述就是C#学习教程：C＃/ SQL：通过复制和替换数据库文件进行备份和还原？分享的全部内容，如果对大家有所用处且需要了解更多关于C#学习教程，希望大家多多关注—计算机技术网（www.ctvol.com）

1）使用的方法

  // fullPath : the path for your database // executablePath : the path for your exe folder void setFullPath() { string executable = System.Reflection.Assembly.GetExecutingAssembly().Location; executablePath = (System.IO.Path.GetDirectoryName(executable)); fullPath = executablePath + "\Database.mdf"; } void takeOffline(string fullPath) { homeObject.connection.Open(); homeObject.cmd.CommandText = "ALTER DATABASE [" + fullPath + "] SET OFFLINE"; homeObject.cmd.ExecuteNonQuery(); homeObject.cmd.Clone(); } void bringOnline(string fullPath) { homeObject.cmd.CommandText = "ALTER DATABASE [" + fullPath + "] SET ONLINE"; ; homeObject.cmd.ExecuteNonQuery(); homeObject.cmd.Clone(); homeObject.connection.Close(); } 

2）复制数据库文件/备份

  bool getDatabaseCopy() { try { // takeOffline(fullPath); // copy database.mdf copyDBMDF(); // copy database_log.ldf copyDB_logLDF(); // bringOnline(fullPath); return true; } catch { // } return false; } // txtPath.txt : // folder location to save database files in void copyDBMDF() { string fileName = "Database.mdf"; string sourceFile = fullPath; string targetPath = txtPath.Text; // Use Path class to manipulate file and directory paths. string destFile = System.IO.Path.Combine(targetPath, fileName); // To copy a folder's contents to a new location: // Create a new target folder, if necessary. if (!System.IO.Directory.Exists(targetPath)) { System.IO.Directory.CreateDirectory(targetPath); } // To copy a file to another location and // overwrite the destination file if it already exists. System.IO.File.Copy(sourceFile, destFile, true); } void copyDB_logLDF() { string fileName = "Database_log.ldf"; string sourcePath = executablePath; string targetPath = txtPath.Text; // Use Path class to manipulate file and directory paths. string sourceFile = System.IO.Path.Combine(sourcePath, fileName); string destFile = System.IO.Path.Combine(targetPath, fileName); // To copy a folder's contents to a new location: // Create a new target folder, if necessary. if (!System.IO.Directory.Exists(targetPath)) { System.IO.Directory.CreateDirectory(targetPath); } // To copy a file to another location and // overwrite the destination file if it already exists. System.IO.File.Copy(sourceFile, destFile, true); } 

3）用您复制/还原的文件替换当前数据库文件

  bool restoreTheBackup() { try { // takeOffline(fullPath); // load .mdf loadMDFDatabaseFile(); // load _log.ldf loadLDFDatabaseFile(); // bringOnline(fullPath); return true; } catch { // } return false; } // txtPath.txt : // location to get database files from to replace with current files. void loadLDFDatabaseFile() { string fileName = "Database_log.ldf"; string targetPath = executablePath; string sourcePath = txtPath.Text; // Use Path class to manipulate file and directory paths. string sourceFile = System.IO.Path.Combine(sourcePath, fileName); string destFile = System.IO.Path.Combine(targetPath, fileName); // To copy a folder's contents to a new location: // Create a new target folder, if necessary. if (!System.IO.Directory.Exists(targetPath)) { System.IO.Directory.CreateDirectory(targetPath); } // To copy a file to another location and // overwrite the destination file if it already exists. System.IO.File.Copy(sourceFile, destFile, true); } void loadMDFDatabaseFile() { string fileName = "Database.mdf"; string targetPath = executablePath; string sourcePath = txtPath.Text; // Use Path class to manipulate file and directory paths. string sourceFile = System.IO.Path.Combine(sourcePath, fileName); string destFile = System.IO.Path.Combine(targetPath, fileName); // To copy a folder's contents to a new location: // Create a new target folder, if necessary. if (!System.IO.Directory.Exists(targetPath)) { System.IO.Directory.CreateDirectory(targetPath); } // To copy a file to another location and // overwrite the destination file if it already exists. System.IO.File.Copy(sourceFile, destFile, true); }