asp.net 2.0下用access开发的时候要注意的问题
來源：http://www.study-code.com/dotnet/aspnet/67492.htm
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１、數據庫要給訪問權限，在我的電腦里，右擊access數據庫，點擊“屬性”菜單，選“安全”選項卡，選擇Users組，賦給完全控制的權限
如果沒有安全選項卡，點擊菜單“工具”->“文件夾選項”，進入“查看”選項卡，把“使用簡單文件共享”前的勾去掉
２、連接數據庫的時候，如果想要做到可以隨時更改數據庫的名稱，也不用重新編譯網站，就把數據庫的路徑記錄在web.config文件里：
??? <connectionStrings>
????? <add name="aceConnectionString" connectionString="目錄\\數據庫名稱.mdb" providerName="System.Data.OleDb" />
??? </connectionStrings>
使用這兩個方法取值：
public static string connectString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=" + HttpContext.Current.Server.MapPath(ConfigurationManager.ConnectionStrings["aceConnectionString"].ConnectionString);
public static string GetDB()
??? {
??????? return HttpContext.Current.Server.MapPath(ConfigurationManager.ConnectionStrings["aceConnectionString"].ConnectionString);
??? }
在每個頁面，如果用到AccessDataSource控件，這個控件是不會自己讀取這個值的，可以在Page_Load頁面里，使用AdsAd.DataFile = NnllClass.GetDB();給他賦值
protected void Page_Load(object sender, EventArgs e)
??? {
??????? AdsAd.DataFile = NnllClass.GetDB();
??? }
３、如果使用AccessDataSource添加、刪除、修改記錄，要注意參數的問題，有一些網站，對一些參數報錯的信息，給出的答案說access數據庫應該使用拼接的sql語句，不可以使用參數，這種說法是不對的，access數據庫也可以使用參數傳遞的方式增刪改查數據庫的
就是，因為vs.net 2005不可以像使用ms sql時一樣子，自動會檢索出參數，所以全部參數要自己手動添加，在添加參數的時候，要很小心，不要少了，也不要多了，也不要搞亂了順序
發現AccessDataSource控件，好像是根據綁定字段的順序來對應傳入的參數的，也就是說，如果你在FormView里，是這樣子綁定的：
<asp:TextBox ID="myField1TextBox" runat="server" Text='<%# Bind("myField1") %>' MaxLength="20"></asp:TextBox>
<asp:TextBox ID="myField2TextBox" runat="server" Text='<%# Bind("myField2") %>' MaxLength="20"></asp:TextBox>
定義參數的時候，就應該這樣子定義：
?<InsertParameters>
??????????? <asp:Parameter Name="myField1" Type="String" Size="20" ConvertEmptyStringToNull="False" />
??????????? <asp:Parameter Name="myField2" Type="String" Size="20" ConvertEmptyStringToNull="False" />
??????? </InsertParameters>
次序不要搞亂了，搞亂了數據格式不同時，會報錯，具體的出錯信息我忘記了
定義參數的時候，還有一個要注意的問題就是，參數名不要寫錯，參數不要寫漏
使用sql數據庫時，參數名不對，或者參數個數不對，都會得到很明顯的出錯信息，就是，access數據庫，在這種時候，是不報錯的，如果參數名寫錯了，只會說有n個參數沒有值，如果是寫漏了參數，他有時候會直接替你更新數據庫，而更新的時候，是以綁定的順序來對應參數的值的，這時候，如果后面的參數值，大于前面的參數對應的字段大小，就會得到“字段太小”的出錯信息
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<InsertParameters>
??????????? <asp:Parameter Name="myField1" Type="String" Size="20" ConvertEmptyStringToNull="False" />
??????????? <asp:Parameter Name="myField2" Type="String" Size="20" ConvertEmptyStringToNull="False" />
??????? </InsertParameters>
如果少了一個
??????????? <asp:Parameter Name="myField3" Type="String" Size="200" ConvertEmptyStringToNull="False" />
在更新的時候，會把myField3的值，寫進myField2里，如果myField3的值的長度大于20，就會報“字段太小”了
３、如果不習慣AccessDataSource控件，那就自己綁定數據吧，給出一些方法：
#region 返回數據庫地址
??? public static string GetDB()
??? {
??????? return HttpContext.Current.Server.MapPath(ConfigurationManager.ConnectionStrings["aceConnectionString"].ConnectionString);
??? }
??? #endregion
???
#region 打開數據庫：SqlConnection OpenConnect()
??? public OleDbConnection OpenConnect(Page aPage,bool setMsg)
??? {
??????? try
??????? {
??????????? OleDbConnection dbConnect = new OleDbConnection(connectString);
??????????? if (!dbConnect.State.Equals(ConnectionState.Open))
??????????? {
??????????????? dbConnect.Open();
??????????? }
??????????? return dbConnect;
??????? }
??????? catch (OleDbException ex)
??????? {
??????????? if (setMsg)
??????????? {
??????????????? SetMsgJS(aPage.Master, "連接數據庫失敗：" + ex.Message.Replace("\n", "").Replace("\r", ""));
??????????? }
??????????? return null;
??????? }
??? }
??? #endregion
???
#region 關閉數據庫：void CloseConnect(SqlConnection dbConnect)
??? public void CloseConnect(OleDbConnection dbConnect)
??? {
??????? if (dbConnect.State.Equals(ConnectionState.Open))
??????? {
??????????? dbConnect.Close();
??????? }
??? }
??? #endregion
???
#region 讀取數據，返回DataSet
??? public DataSet GetDataSet(Page aPage, OleDbConnection dbConnection, CommandType commandType, string commandText, out string msg, bool setMsg)
??? {
??????? msg = "";
??????? //創建并設置SqlCommand
??????? OleDbCommand dbCommand = new OleDbCommand();
??????? dbCommand.Connection = dbConnection;
??????? dbCommand.CommandType = commandType;
??????? dbCommand.CommandText = commandText;
??????? //創建SqlDataAdapter并獲取數據
??????? DataSet ds = new DataSet();
??????? try
??????? {
??????????? OleDbDataAdapter dataAdapter = new OleDbDataAdapter(dbCommand);
??????????? dataAdapter.Fill(ds);
??????? }
??????? catch (InvalidOperationException eo)
??????? {
??????????? msg = "讀取數據失敗：" + eo.Message.Replace("\n", "").Replace("\r", "") + "\\n";
??????????? if (setMsg)
??????????? {
??????????????? SetMsgJS(aPage.Master, msg);
??????????? }
??????? }
??????? catch (OleDbException ex)
??????? {
??????????? msg = "讀取數據失敗：" + ex.Message.Replace("\n", "").Replace("\r", "") + "\\n";
??????????? if (setMsg)
??????????? {
??????????????? SetMsgJS(aPage.Master, msg);
??????????? }
??????? }
??????? //返回數據
??????? return ds;
??? }
??? #endregion
???
#region 讀取數據，返回SqlDataReader
??? public OleDbDataReader GetDataReader(Page aPage, OleDbConnection dbConnection, CommandType commandType, string commandText, OleDbParameter[] p, out string msg, bool setMsg)
??? {
??????? msg = "";
??????? //設置命令
??????? OleDbCommand dbCommand = new OleDbCommand();
??????? dbCommand.Connection = dbConnection;
??????? dbCommand.CommandType = commandType;
??????? dbCommand.CommandText = commandText;
??????? //設置參數
??????? if (p != null)
??????? {
??????????? foreach (OleDbParameter pi in p)
??????????? {
??????????????? dbCommand.Parameters.Add(pi);
??????????? }
??????? }
??????? //讀取第一個結果集
??????? OleDbDataReader dbReader = null;
??????? try
??????? {
??????????? dbReader = dbCommand.ExecuteReader();
??????? }
??????? catch (InvalidOperationException eo)
??????? {
??????????? msg = "讀取數據失敗：" + eo.Message.Replace("\n", "").Replace("\r", "") + "\\n";
??????????? if (setMsg)
??????????? {
??????????????? SetMsgJS(aPage.Master, msg);
??????????? }
??????? }
??????? catch (OleDbException ex)
??????? {
??????????? msg = "讀取數據失敗：" + ex.Message.Replace("\n", "").Replace("\r", "") + "\\n";
??????????? if (setMsg)
??????????? {
??????????????? SetMsgJS(aPage.Master, msg);
??????????? }
??????? }
??????? return dbReader;
??? }
??? #endregion
???
#region 執行sql命令或存儲過程
??? public int execCommand(Page aPage, OleDbConnection dbConnection, CommandType commandType, string commandText, OleDbParameter[] p, out string msg, bool setMsg)
??? {
??????? bool needCloseDB = false;
??????? int row = 0;
??????? msg = "";
??????? //創建并設置SqlConnection
??????? if (dbConnection == null)
??????? {
??????????? needCloseDB = true;
??????????? dbConnection = OpenConnect(aPage, setMsg);
??????????? if (dbConnection == null) return -1;
??????? }
??????? //創建并設置SqlCommand
??????? OleDbCommand dbCommand = new OleDbCommand();
??????? dbCommand.Connection = dbConnection;
??????? dbCommand.CommandType = commandType;
??????? dbCommand.CommandText = commandText;
??????? //設置參數
??????? if (p != null)
??????? {
??????????? foreach (OleDbParameter pi in p)
??????????? {
??????????????? dbCommand.Parameters.Add(pi);
??????????? }
??????? }
??????? //執行命令
??????? try
??????? {
??????????? row = dbCommand.ExecuteNonQuery();
??????? }
??????? catch (InvalidOperationException eo)
??????? {
??????????? msg = eo.Message.Replace("\n", "").Replace("\r", "") + "\\n";
??????????? if (setMsg)
??????????? {
??????????????? SetMsgJS(aPage.Master, msg);
??????????? }
??????????? row = -1;
??????? }
??????? catch (OleDbException ex)
??????? {
??????????? //執行過程出錯
??????????? msg = ex.Message.Replace("\n", "").Replace("\r", "") + "\\n";
??????????? if (setMsg)
??????????? {
??????????????? SetMsgJS(aPage.Master, msg);
??????????? }
??????????? row = -1;
??????? }
??????? //關閉數據庫
??????? if (needCloseDB)
??????? {
??????????? CloseConnect(dbConnection);
??????? }
??????? return row;
??? }
??? #endregion
上面的方法都用到一個SetMsgJS方法，這個方法是用來給母版頁設置信息的
public static void SetMsgJS(MasterPage masterPage, string msg)
??? {
??????? Literal lt = (Literal)masterPage.FindControl("LiteralMsg");
??????? if (lt != null)
??????? {
??????????? lt.Text += msg;
??????? }
??? }
在母版頁里定義是這樣子的：
???
<script type="text/javascript">
??????? var msg = "";
??????? msg = "<asp:Literal ID="LiteralMsg" runat="server"></asp:Literal>";
??????? if(msg != "")
??????? {
??????????? alert(msg);
??????? }
??? </script>
轉載于:https://www.cnblogs.com/kangshifu/archive/2008/08/11/1265124.html
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