我正在尝试更新访问文件（.accdb）中的记录。我正在尝试使用.net OleDbCommand和OleDbParameters。我也尝试使用通用模型并将所有命令和参数存储在System.Data.Common抽象等价物中，以便我可以轻松切换到SQL Server（我打算这样做）
所以这是使用的实际命令
编辑2013年2月2日 - 晚上9:10 command.ExecuteNonQuery位于名为ExecuteNonQuery（）的方法内 connectionString和command在DataAccess类构造函数
中定义public class DataAccess
{
private string connectionString;
private DbConnection connection;
private DbCommand command;
private DbDataReader reader;
private DataTable data;
public DataAccess()
{
connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
switch (ConfigurationSettings.AppSettings["DataBaseType"])
{
case "oledb":
connection = new OleDbConnection(connectionString);
command = new OleDbCommand(string.Empty, (OleDbConnection)connection);
break;
case "SQL":
connection = new SqlConnection(connectionString);
command = new SqlCommand(string.Empty, (SqlConnection)connection);
break;
default:
break;
}
}
public void ExecuteNonQuery(string SQL, params DbParameter[] parameters)
{
command.CommandType = CommandType.Text;
command.CommandText = SQL;
command.Parameters.AddRange(parameters);
try
{
command.Connection.Open();
try
{
command.ExecuteNonQuery();
}
catch (Exception ex)
{
throw ex;
}
finally
{
command.Connection.Close();
}
}
catch (Exception ex)
{
throw ex;
}
}
public DbParameter NewParameter(string name, object value)
{
DbParameter param;
switch (ConfigurationSettings.AppSettings["DataBaseType"])
{
case "oledb":
param = new OleDbParameter(name, value);
break;
case "SQL":
param = new SqlParameter(name, value);
break;
default:
param = null;
break;
}
return param;
}
这些是App.Config文件中的属性
<add key="DataBaseType" value="oledb"/>
<add key="ConnectionString" value="Provider=Microsoft.ACE.OLEDB.12.0;Data Source=data.accdb"/>
现在问题是在更新语句中使用参数时，更新永远不会发生，也永远不会抛出错误。这是它的代码。
编辑2013年2月2日 - 晚上9:10 函数DataAccess.NewParameter位于第一个代码块
中DALayer.ExecuteNonQuery("UPDATE TileTypes SET Title = @Title, Picture = @Picture, Color = @Color WHERE ID = @ID",
DALayer.NewParameter("@Title", titleTextBox.Text.Trim()),
DALayer.NewParameter("@Picture", typePictureBox.ImageLocation),
DALayer.NewParameter("@Color", colorButton.BackColor.ToArgb()),
DALayer.NewParameter("@ID", id));
我已将查询复制到访问中，并将所有参数名称替换为传递的实际数据，这样可以正常工作。我试过将SQL文本中的所有参数替换为？性格无效。我已经尝试将括号[]中的所有表名和列名括起来也没有效果。
这是直接从Visual Studio观察窗口中的参数复制的一些示例数据：
该ID确实存在于数据库中，并且在执行查询后未更改。
编辑2013年2月2日 - 晚上9:10 我不确定如何检查哪个数据库实际上正在更新，我唯一能想到的是使用相同的连接字符串和连接对象我使用相同的ExecuteNonquery方法执行了一个insert语句，它在我正在查看的数据库中工作。并且update语句可以正常工作（没有参数）：
DALayer.ExecuteNonQuery("UPDATE TileTypes SET Title = '" + titleTextBox.Text +
"', Color = " + colorButton.BackColor.ToArgb() + ", Picture = '" +
imageLocation + "' WHERE ID = " + id);
编辑2/2/2013 - 9:41 pm 我已经使用everything.exe在我的计算机上搜索我计算机上的所有data.accdb文件，我发现除了原始文件之外没有实际的.accdb文件，但我确实找到了这些.lnk文件，我不相信它们可能会有变化这个过程，但无论如何我都会提到它
data.accdb.LNK
答案 0 :(得分：0)
您尝试做的事情是我过去也做过的事情，但允许连接到OleDB（例如Access，Visual FoxPro等），SQL-Server，SyBase SQLAnywhere，也许我的实现可能对您有帮助。首先，您将用于连接公共接口上的每个元素，例如IDbConnection，IDbCommand，IDbParameter等。
以下我发布的内容是我最初构建此类多数据库连接类型的一小部分。我已经删除了一堆并没有实际测试这个剥离版本，但它应该是你运行的良好基线。
前提是基线“MyConnection”几乎就像一个抽象，但具有属性和一些“常见”方法，这些方法将存在于EITHER子类定义下。由此，每个函数和参数类型都基于“I”接口，而不是特定的。但是，每个派生的都将创建其OWN正确类型。这消除了“案例”一切的需要。希望这可以帮助您进行数据访问层开发。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
// for OleDB (Access, VFP, etc)
using System.Data.OleDb;
// for SQL-Server
using System.Data.SqlClient;
namespace DataMgmt
{
public class MyConnection
{
// no matter the connection to server, it will require some "handle"
// that is of type "IDbConnection"
protected IDbConnection sqlConnectionHandle;
// when querying, ANY query could have an exception that needs to have
// possible further review for handling
public Exception LastException
{ get; protected set; }
// When calling an execute command (select, insert, update, delete),
// they all can return how many rows affected
public int RowsAffectedByQuery
{ get; protected set; }
// different databases could have different connection strings. Make
// virtual and throw exception so sub-classed must return proper formatted.
public virtual string GetConnectionString()
{ throw new Exception("GetConnectionString() method must be overridden."); }
// each has its own "IDbConnection" type too
protected virtual IDbConnection SQLConnectionHandle()
{ return sqlConnectionHandle; }
public virtual IDbCommand GetSQLDbCommand()
{ throw new Exception("GetSQLDbCommand() method must be overridden."); }
// generic routine to get a data parameter...
public virtual IDbDataParameter AddDbParmSpecificValue(string ParmName, object UnknownValue)
{ throw new Exception("AddDbParmSpecificValue() method must be overwritten per specific connection."); }
// generic "Connection" since they are all based on IDbCommand...
public override bool SQLConnect()
{
// pre-blank exception in case remnant from previous activity
LastException = null;
if (sqlConnectionHandle.State != System.Data.ConnectionState.Open)
try
{
// if not open, always make sure we get updated connection string
// if ever changed by some other "unknown" condition...
sqlConnectionHandle.ConnectionString = GetConnectionString();
sqlConnectionHandle.Open();
}
catch (Exception ex)
{
// Preserve in generic sqlException" property for analysis OUTSIDE this function
LastException = ex;
}
// if NOT connected, display message to user and set error code and exception
if (sqlConnectionHandle.State != System.Data.ConnectionState.Open)
LastException = new Exception("Unable to open database connection.");
// return if it IS successful at opening the connection (or was already open)
return sqlConnectionHandle.State == System.Data.ConnectionState.Open;
}
// likewise disconnect could be common
public void SQLDisconnect()
{
if (sqlConnectionHandle != null)
if (sqlConnectionHandle.State == ConnectionState.Open)
sqlConnectionHandle.Close();
}
public bool SqlExecNonQuery( IDbCommand SQLCmd, DataTable oTbl)
{
// pre-clear exception
LastException = null;
// fill the table...
SQLConnect();
try
{
RowsAffectedByQuery = SQLCmd.ExecuteNonQuery();
}
catch (Exception e)
{
LastException = e;
throw e;
}
finally
{
SQLDisconnect();
}
// Its all ok if no exception error
return LastException == null;
}
}
// Now, build your connection manager per specific type
public class MyAccessConnection : MyConnection
{
public MyAccessConnection()
{ sqlConnectionHandle = new OleDbConnection(); }
public override string GetConnectionString()
{ return "Your Connection String from AppSettings.. any changes if OleDb vs SQL"; }
public override IDbCommand GetSQLDbCommand()
{ return new OleDbCommand( "", (OleDbConnection)sqlConnectionHandle ); }
public override IDbDataParameter AddDbParmSpecificValue(string ParmName, object UnknownValue)
{ return new OleDbParameter( ParmName, UnknownValue ); }
}
public class MySQLConnection : MyConnection
{
public MySQLConnection()
{ sqlConnectionHandle = new SqlConnection(); }
public override string GetConnectionString()
{ return "Your Connection String from AppSettings... any alterations needed??? "; }
public override IDbCommand GetSQLDbCommand()
{ return new SqlCommand ("", (SqlConnection)sqlConnectionHandle); }
public override IDbDataParameter AddDbParmSpecificValue(string ParmName, object UnknownValue)
{ return new SqlParameter(ParmName, UnknownValue); }
}
// Now to implement... pick one... Access or SQL-Server for derivation...
public class MyDataLayer : MyAccessConnection
{
public void SomeSQLCall()
{
IDbCommand sqlcmd = GetSQLDbCommand();
sqlcmd.CommandText = "UPDATE TileTypes SET Title = @Title, "
+ "Picture = @Picture, "
+ "Color = @Color "
+ "WHERE ID = @ID";
sqlcmd.Parameters.Add( AddDbParmSpecificValue( "@Title", titleTextBox.Text.Trim() ));
sqlcmd.Parameters.Add( AddDbParmSpecificValue( "@Picture", typePictureBox.ImageLocation) );
sqlcmd.Parameters.Add( AddDbParmSpecificValue( "@Color", colorButton.BackColor.ToArgb()) );
sqlcmd.Parameters.Add( AddDbParmSpecificValue( "@ID", id));
if( SqlExecNonQuery(sqlcmd))
// Good to go
DoSomethingWithTheData;
else
// Notify of whatever error thrown....
}
}
}
所以..正如你所看到的，我的最后一节特别是从EITHER Access OR SQL派生而来。然后，我可以创建我的方法来获取数据，调用更新，等等。获取一个SQL命令（返回正确的类型并自动附加到其对应的“连接句柄”对象，准备文本，添加参数，执行它。