ADO.Net中通过HashTable对SqlParameter赋值的三种方法和返回DataTable的两种方式

一、得到数据库连接

/// <summary>
/// 得到数据连接
/// </summary>
/// <returns>返回连接字符串</returns>

private string getConnectionString()
{
string strConn = ConfigurationSettings.AppSettings["ConnectionString"].ToString();
return strConn;
}
二、执行操作

/// <summary>
/// 执行sqlCommand
/// </summary>
/// <param name="sqlCommand">待执行的sql语句或存储过程名</param>
/// <param name="htParameters">参数集</param>
/// <returns>数据集</returns>

public DataTable ExecuteSqlCommand(string sqlCommand,Hashtable htParameters)
{
string strConn = this.getConnectionString();

SqlConnection sqlConn = new SqlConnection(strConn);

SqlTransaction sqlTran = sqlConn.BeginTransaction();

DataTable dtReturn = new DataTable();

try
{
if (sqlConn.State == ConnectionState.Closed)
{
sqlConn.Open();
}

SqlCommand sqlCom = sqlConn.CreateCommand();

sqlCom.CommandType = CommandType.Text;

sqlCom.CommandText = sqlCommand;

/*
//当sqlCommand为存储过程名时，应为如下所示

sqlCom.CommandType = CommandType.StoredProcedure;

sqlCom.CommandText = sqlCommand;
*/

/*
//以下为通过Hashtable对sqlcommand赋参的三种方法
*/
//

//
//方法一、通过IDictionaryEnumerator接口赋值
//

IDictionaryEnumerator iDictionary = htParameters.GetEnumerator();

while (iDictionary.MoveNext())
{
object objKey = iDictionary.Key;

sqlCom.Parameters.Add(objKey.ToString());

sqlCom.Parameters[objKey.ToString()].Value = iDictionary.Value;
}

//
//方法二、通过OBJECT赋值
//
foreach (object objKeys in htParameters.Keys)
{
sqlCom.Parameters.Add(objKeys);

sqlCom.Parameters[objKeys.ToString()].Value = htParameters[objKeys];
}
//
//方法三、通过DictionaryEntry赋值
//
foreach (DictionaryEntry dEntry in htParameters)
{
sqlCom.Parameters.Add(dEntry.Key);

sqlCom.Parameters[dEntry.Key.ToString()].Value = dEntry.Value;
}

/*
//以下为返回结果数据集以DataTable返回的两种方法
//
//DataReader数据不在内存中缓存，适合于检索大量数据
//
*/
//
//方法一、以SqlDataReader的形式返回DataTable数据集
//

SqlDataReader sqlReader = sqlCom.ExecuteReader();

if (sqlReader.HasRows)
{
dtReturn = sqlReader.GetSchemaTable();
}

//
//方法二、以DataSet的形式返回DataTable数据集
//

SqlDataAdapter sqlData = new SqlDataAdapter(sqlCom);

DataSet dtSet = new DataSet();

sqlData.Fill(dtSet);

dtReturn = dtSet.Tables[0];

}
catch (Exception ce)
{
sqlTran.Rollback();
throw new ApplicationException(ce.Message.ToString());
}
finally
{
sqlTran.Commit();

if (sqlConn.State == ConnectionState.Open)
{
sqlConn.Close();
}
}

return dtReturn;
}