查询得到OleDbDataReader后，有三种方式支持数据读取，如下：
//方法一**速度中等
OleDbDataReader reader = command.ExecuteReader();
while (reader.Read())
{
var t1 = reader[];
} //方法二**速度最慢
OleDbDataReader reader = command.ExecuteReader();
while (reader.Read())
{
var t1 = reader["字段名"];
} //方法三**速度最快
OleDbDataReader reader = command.ExecuteReader();
while (reader.Read())
{
var t1 = reader.GetValue();
}
关于速度的描述，下面我们来简单验证一下。
有一个数据库，数据库中的表TEST有105945行数据，设计一个循环读取来测试他们的读取速度。
测试源码如下：
static void Main(string[] args)
{
string connstr = string.Format("Provider=Microsoft.Jet.OLEDB.4.0 ;Data Source={0};", "F:\\2.mdb");
string s1 = "ID";
string s2 = "探测号";
string s3 = "X";
string s4 = "Y";
string s5 = "H";
string sql = string.Format("SELECT {0},{1},{2},{3},{4} FROM 管点表", s1, s2, s3, s4, s5);
TimeSpan time1 = new TimeSpan();
TimeSpan time2 = new TimeSpan();
TimeSpan time3 = new TimeSpan(); int count = ; //数据库中查询的表有105945行
for (int i = ; i < count; i++)
{
using (OleDbConnection conn = new OleDbConnection(connstr))
{
#region
conn.Open();
OleDbCommand command = conn.CreateCommand();
command.CommandText = sql;
OleDbDataReader reader = command.ExecuteReader();
DateTime now = DateTime.Now;
while (reader.Read())
{
var t1 = reader[]; var t2 = reader[]; var t3 = reader[]; var t4 = reader[]; var t5 = reader[];
}
time1 = time1 + (DateTime.Now - now);
#endregion
}
}
for (int i = ; i < count; i++)
{
using (OleDbConnection conn = new OleDbConnection(connstr))
{
#region
conn.Open(); OleDbCommand command2 = conn.CreateCommand();
command2.CommandText = sql;
OleDbDataReader reader = command2.ExecuteReader();
DateTime now = DateTime.Now;
while (reader.Read())
{
var t1 = reader[s1]; var t2 = reader[s2]; var t3 = reader[s3]; var t4 = reader[s4]; var t5 = reader[s5];
}
time2 = time2 + (DateTime.Now - now);
#endregion
}
}
for (int i = ; i < count; i++)
{
using (OleDbConnection conn = new OleDbConnection(connstr))
{
#region
conn.Open(); OleDbCommand command3 = conn.CreateCommand();
command3.CommandText = sql;
OleDbDataReader reader = command3.ExecuteReader();
DateTime now = DateTime.Now;
while (reader.Read())
{
var t1 = reader.GetValue(); var t2 = reader.GetValue(); var t3 = reader.GetValue(); var t4 = reader.GetValue(); var t5 = reader.GetValue();
}
time3 = time3 + (DateTime.Now - now);
#endregion
}
}
Console.WriteLine(string.Format("方法一：\r\n耗时：{0}s", time1.TotalSeconds));
Console.WriteLine(string.Format("方法二：\r\n耗时：{0}s", time2.TotalSeconds));
Console.WriteLine(string.Format("方法三：\r\n耗时：{0}s", time3.TotalSeconds));
Console.ReadKey();
}
循环50次结果，即50*105945：
100次循环结果:，即100*105945：