DataReader 不是return数据而是行数
DataReader does not return data but the number of rows
我有这个代码
string query = "SELECT * FROM table;"
try
{
using (SqlConnection connection = new SqlConnection(this.ConnectionString))
{
connection.Open();
using (SqlCommand cmd = new SqlCommand(query, connection))
{
SqlDataReader reader = cmd.ExecuteReader();
}
connection.Close();
}
}
在reader中我收到了table中的行数,但没有数据。我在哪里迷路了?
调用 ExecuteReader
后,您需要遍历它,读取每一行:
while(reader.Read())
{
// Process the row...
}
此外,最好将 reader 放入 using
块中:
using(SqlDataReader reader = cmd.ExecuteReader())
{
while(reader.Read())
{
// Process the row
}
}
您需要阅读 reader
SqlDataReader reader = command.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
//
}
}
我有这个代码
string query = "SELECT * FROM table;"
try
{
using (SqlConnection connection = new SqlConnection(this.ConnectionString))
{
connection.Open();
using (SqlCommand cmd = new SqlCommand(query, connection))
{
SqlDataReader reader = cmd.ExecuteReader();
}
connection.Close();
}
}
在reader中我收到了table中的行数,但没有数据。我在哪里迷路了?
调用 ExecuteReader
后,您需要遍历它,读取每一行:
while(reader.Read())
{
// Process the row...
}
此外,最好将 reader 放入 using
块中:
using(SqlDataReader reader = cmd.ExecuteReader())
{
while(reader.Read())
{
// Process the row
}
}
您需要阅读 reader
SqlDataReader reader = command.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
//
}
}