c# - SqlConnection 问题，ASP.net C#

Question

我有以下 C# 代码:

public string TargetDate()
{
    SqlConnection con = 
        new SqlConnection("Server=localhost;Database=Timer;Trusted_Connectopn=True");
    SqlCommand cmd = new SqlCommand("select * from Timer");
    con.Open(); 

    DataSet ds = new DataSet(cmd,con); 
    SqlDataAdapter da = new SqlDataAdapter(); 
    da.Fill(ds); 
    con.Close(); 
}

但我在以下位置遇到错误:new DataSet(cmd,con); ...

the error: CS1502: The best overloaded method match for

'System.Data.DataSet.DataSet(System.Runtime.Serialization.SerializationInfo,

System.Runtime.Serialization.StreamingContext)' has some invalid arguments

可能是什么问题？

Answer 1

试试这个:

SqlConnection con = new SqlConnection
    ("Server=localhost;Database=Timer;Trusted_Connection=True");

SqlCommand cmd = new SqlCommand("select * from Timer", con);

con.Open();

DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(ds);

con.Close(); 

这更好:

DataTable dataTable = new DataTable();
using(SqlConnection connection = new SqlConnection("Server=localhost;Database=Timer;Trusted_Connection=True"))
using(SqlCommand command = connection.CreateCommand())
{
    command.CommandText = "select * from Timer";
    connection.Open();
    SqlDataReader reader = command.ExecuteReader();
    dataTable.Load(reader);
}