public int ExecuteNonQuery(string cmdText, SqlParameter[] paras, CommandType ct)
{
int res;
using (cmd = new SqlCommand(cmdText, GetConn()))
{
cmd.CommandType = ct;
cmd.Parameters.AddRange(paras);
res = cmd.ExecuteNonQuery();
}
return res;
}这里面的 using 有什么用呢?不用using应该怎么写呢?
{
int res;
using (cmd = new SqlCommand(cmdText, GetConn()))
{
cmd.CommandType = ct;
cmd.Parameters.AddRange(paras);
res = cmd.ExecuteNonQuery();
}
return res;
}这里面的 using 有什么用呢?不用using应该怎么写呢?
try
{
}
catch
{
}
{
int res;
try
{
cmd = new SqlCommand(cmdText, GetConn());
cmd.CommandType = ct;
res = cmd.ExecuteNonQuery();
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (conn.State == ConnectionState.Open)
{
conn.Close();
}
}
return res;
}这种写法和用 using 哪种好呢
释放对象,只有实现Idisposable接口的类才能用using()
using(classA ObjA=new ClassA())
{
...
}等价于classA ObjA=new ClassA();
try
{
}
finally
{
ObjA.Dispose();
}