/// <summary>
/// 得到该节点下的最大值Id
/// </summary>
/// <param name="linkid"></param>
/// <returns></returns>
public Test GetMaxId(int linkid)
{
try
{
String sql = "select max(Id) from test3 where linkid=@linkid" ;
SqlDataReader sdr = DBHelper.GetReader(sql,new SqlParameter("@linkid",linkid));
if (sdr.Read())
{
Test test = new Test(); test.Id = Convert.ToInt32(sdr["Id"].ToString());
test.Name = (string)sdr["name"];
test.LinkId = (int)sdr["LinkId"];
test.Classid = (int)sdr["ClassId"];
sdr.Close();
return test;
}
else
{
sdr.Close();
return null;
}
}
catch (Exception e)
{
throw e;
}
}
直接出异常 请高手指点
/// 得到该节点下的最大值Id
/// </summary>
/// <param name="linkid"></param>
/// <returns></returns>
public Test GetMaxId(int linkid)
{
try
{
String sql = "select max(Id) from test3 where linkid=@linkid" ;
SqlDataReader sdr = DBHelper.GetReader(sql,new SqlParameter("@linkid",linkid));
if (sdr.Read())
{
Test test = new Test(); test.Id = Convert.ToInt32(sdr["Id"].ToString());
test.Name = (string)sdr["name"];
test.LinkId = (int)sdr["LinkId"];
test.Classid = (int)sdr["ClassId"];
sdr.Close();
return test;
}
else
{
sdr.Close();
return null;
}
}
catch (Exception e)
{
throw e;
}
}
直接出异常 请高手指点
select max(Id)
出一个字段,怎么能读取到 test.Id = Convert.ToInt32(sdr["Id"].ToString());
test.Name = (string)sdr["name"];
test.LinkId = (int)sdr["LinkId"];
test.Classid = (int)sdr["ClassId"];这4个字段的内容呢?
SqlDataReader sdr = DBHelper.GetReader(sql,new SqlParameter("@linkid",linkid));
if (sdr.Read())
{
int maxID = 0;
if(sdr[0]!=DBNull.Value)
{
maxID = ConvertToInt32(sdr[0].ToString());} sdr.Close();
sql = "select * from test3 where Id=" + maxID ;
sdr = DBHelper.GetReader(sql,new SqlParameter("@linkid",linkid));
if (sdr.Read())
{
Test test = new Test(); test.Id = Convert.ToInt32(sdr["Id"].ToString());
test.Name = (string)sdr["name"];
test.LinkId = (int)sdr["LinkId"];
test.Classid = (int)sdr["ClassId"];
sdr.Close();
return test;
}
else
{
sdr.Close();
return null;
} }