110,537
社区成员
发帖
与我相关
我的任务
分享
//方式一 手动Dispose
SqlCommand cmd = new SqlCommand();
cmd.Connection = new SqlConnection(@"Data Source = .\sqlexpress;Initial Catalog=Master;User Id=sa;Password=1;");
cmd.CommandText = "select * from XXX";
cmd.Dispose(); //终结这个对象
cmd.Connection.Open(); //Connection对象能正常访问
Console.WriteLine(cmd.ExecuteScalar()); //执行正常
//方式二 使用using,Connection在using外定义
SqlConnection conn = new SqlConnection(@"Data Source = .\sqlexpress;Initial Catalog=Master;User Id=sa;Password=1;");
using(SqlCommand cmd = new SqlCommand())
{
cmd.Connection = conn;
cmd.CommandText = "select * from XXX";
} //终结这个对象
conn.Open();//Connection对象能正常访问
Console.WriteLine(cmd.ExecuteScalar()); //执行正常
SqlCommand cmd = null;
SqlConnection conn = new SqlConnection(@"Data Source = .\sqlexpress;Initial Catalog=Master;User Id=sa;Password=1;");
using(cmd = new SqlCommand())
{
cmd.Connection = conn;
cmd.CommandText = "select count(*) from XXX";
} //终结这个对象
conn.Open();//Connection对象能正常访问
Console.WriteLine(cmd.ExecuteScalar()); //执行正常