[Access] C# 通过 COM 组件访问 Access 文件

说明：

1，采用 dynamic 调用 COM 组件，适用于 .NET 4.0 以上支持 dynamic 版本的才可以；

2，执行速度不敢恭维，只是因为要用于 Silverlight OOB 模式中才研究一二；

3，测试环境 .net 4.5 + Silverlight 5.0 + Visual Studio 2013

4，见如下 helper 类（需引用 using System.Runtime.InteropServices.Automation;）：

 public class SLAccessHelper
 {
     private dynamic m_AccessApp;// Access.Application
     private dynamic m_Database;// Database
     private dynamic m_Recordset;

     /// <summary>
     /// 构造函数
     /// </summary>
     /// <param name="visible">Access是否可见</param>
     public SLAccessHelper(bool visible)
     {
         m_AccessApp = AutomationFactory.CreateObject("Access.Application");
         m_AccessApp.Visible = visible;
     }

     /// <summary>
     /// 打开数据库
     /// </summary>
     /// <param name="filePath">Access数据库文件路径</param>
     /// <param name="exclusive">是否共享</param>
     /// <param name="bstrPassword">密码</param>
     public void OpenDb(string filePath, bool exclusive = false, string bstrPassword = "")
     {
         m_AccessApp.OpenCurrentDatabase(filePath, exclusive, bstrPassword);
         m_Database = m_AccessApp.CurrentDb();
     }

     /// <summary>
     /// 获取当前数据库中所有表名称集合
     /// </summary>
     /// <returns>所有表名称集合</returns>
     public List<string> GetTableNames()
     {
         List<string> tableNames = new List<string>();
         dynamic tableDefs = m_Database.TableDefs;
         foreach (dynamic tableDef in tableDefs)
         {
             tableNames.Add(tableDef.Name);
         }

         return tableNames;
     }

     /// <summary>
     /// 加载表数据
     /// </summary>
     /// <param name="tableName">表名称</param>
     /// <returns>表数据</returns>
     public List<List<string>> LoadTable(string tableName)
     {
         dynamic recordSet = m_Database.OpenRecordset(tableName);
         int fieldsCount = recordSet.Fields.Count;
         List<List<string>> data = new List<List<string>>();
         if (fieldsCount > )
         {
             try
             {
                 List<string> fieldNames = new List<string>();
                 for (int i = ; i < fieldsCount; i++)
                 {
                     fieldNames.Add(recordSet.Fields[i].Name);
                 }
                 data.Add(fieldNames);
                 if (!recordSet.EOF)
                 {
                     recordSet.MoveFirst();
                     while (!recordSet.EOF)
                     {
                         object[] dataRow = recordSet.GetRows();// 返回一维数组
                         List<string> dataRowStr = new List<string>();
                         for (int i = ; i < dataRow.Length; i++)
                         {
                             dataRowStr.Add(dataRow[i] == null ? "" : dataRow[i].ToString());
                         }
                         data.Add(dataRowStr);
                     }
                 }
             }
             catch (Exception ex)
             {
                 throw new Exception(ex.Message);
             }
             finally
             {
                 if (recordSet != null)
                 {
                     recordSet.Close();
                     ((IDisposable)recordSet).Dispose();
                     recordSet = null;
                 }
             }
         }

         return data;
     }

     /// <summary>
     /// 添加新纪录
     /// </summary>
     /// <param name="tableName">表格名称</param>
     /// <param name="data">数据</param>
     public void AddNewRecord(string tableName, List<Dictionary<string, object>> data)
     {
         try
         {
             m_Recordset = m_Database.OpenRecordset(tableName, );// 1=RecordsetTypeEnum.dbOpenTable
             int fieldsCount = m_Recordset.Fields.Count;
             List<string> fieldNames = new List<string>();
             for (int i = ; i < fieldsCount; i++)
             {
                 fieldNames.Add(m_Recordset.Fields[i].Name);
             }
             for (int rowIndex = ; rowIndex < data.Count; rowIndex++)
             {
                 m_Recordset.AddNew();
                 foreach (string fieldName in fieldNames)
                 {
                     m_Recordset.Fields[fieldName].Value = data[rowIndex][fieldName];
                 }
                 m_Recordset.Update();
             }
         }
         catch(Exception ex)
         {
             throw new Exception(ex.Message);
         }
         finally
         {
             if (m_Recordset != null)
             {
                 m_Recordset.Close();
                 ((IDisposable)m_Recordset).Dispose();
                 m_Recordset = null;
             }
         }
     }

     /// <summary>
     /// 更新表格数据
     /// </summary>
     /// <param name="tableName">表格名称</param>
     /// <param name="data">数据</param>
     public void UpdateTable(string tableName, List<Dictionary<string, string>> data)
     {
         try
         {
             m_Recordset = m_Database.OpenRecordset(tableName, );// 1=RecordsetTypeEnum.dbOpenTable
             m_Recordset.MoveFirst();
             for (int rowIndex = ; rowIndex < data.Count; rowIndex++)
             {
                 m_Recordset.Edit();
                 foreach (string fieldName in data[rowIndex].Keys)
                 {
                     m_Recordset.Fields[fieldName].Value = data[rowIndex][fieldName];
                 }
                 m_Recordset.Update();
                 m_Recordset.MoveNext();
             }
         }
         catch (Exception ex)
         {
             throw new Exception(ex.Message);
         }
         finally
         {
             if (m_Recordset != null)
             {
                 m_Recordset.Close();
                 ((IDisposable)m_Recordset).Dispose();
                 m_Recordset = null;
             }
         }
     }

     /// <summary>
     /// 关闭
     /// </summary>
     public void Close()
     {
         if (m_Database != null)
         {
             m_Database.Close();
             ((IDisposable)m_Database).Dispose();
             m_Database = null;
         }
         if (m_AccessApp != null)
         {
             m_AccessApp.CloseCurrentDatabase();
             // m_AccessApp.Quit();// 导致最后会弹出Access主页面
             ((IDisposable)m_AccessApp).Dispose();
             m_AccessApp = null;
         }
         GC.Collect();
     }
 }

 

通过 dynamic 构建的 COM 对象，在使用完成后都要手动关闭销毁，比如代码中的 m_AccessApp, m_Database, m_Recordset 三个对象，否则只是将 m_AccessApp 关闭清空释放掉，Access 进程还是无法关闭，在程序关闭之前，始终都会有一个空白的无法关闭的 Access 界面；

在循环中处理 dynamic 和 C# 类型转换会降低程序执行效率，就比如像 GetTableNames 方法中循环遍历表名，都要花两三秒时间，所以尽量像 object[] dataRow = recordSet.GetRows(); 直接获取其中的所有数据，然后再遍历处理，会极大提高执行效率；

要修改 Access 中的数据时，一定要先 m_Recordset.Edit(); 才会允许你编辑其中的内容；