我在使用的分类信息的时候需要添加联动属性，结果去添加联动属性的时候，发现只可以添加一级联动和三级联动。

二级联动无法添加了。

在自己的5.6的后台添加的时候，发现是可以的。估计又是5.7版本的bug了。

于是分析了代码，和大家分享下解决的办法：
首先我们找到我们的模板源码下面的 dede/stepselect_main.php 这个文件，

将这段代码

else if($action=='addenum_save')
{
if(empty($ename) || empty($egroup))
{
Showmsg("类别名称或组名称不能为空！","-1");
exit();
}
if($issign == 1 || $topvalue == 0)
{
$enames = explode(',', $ename);
foreach($enames as $ename)
{
$arr = $dsql->GetOne("SELECT * FROM `dede_sys_enum` WHERE egroup='$egroup' AND (evalue MOD 500)=0 ORDER BY disorder DESC ");
if(!is_array($arr)) $disorder = $evalue = ($issign==1 ? 1 : 500);
else $disorder = $evalue = $arr['disorder'] + ($issign==1 ? 1 : 500);

$dsql->ExecuteNoneQuery("INSERT INTO `dede_sys_enum`(`ename`,`evalue`,`egroup`,`disorder`,`issign`)
VALUES('$ename','$evalue','$egroup','$disorder','$issign'); ");
}
WriteEnumsCache($egroup);
ShowMsg("成功添加枚举分类！".$dsql->GetError(), $ENV_GOBACK_URL);
exit();
} else if ($issign == 2 && $topvalue != 0)
{
$minid = $topvalue;
$maxnum = 500; // 三级子类最多500个
$enames = explode(',', $ename);
foreach ($enames as $ename)
{
$arr = $dsql->GetOne("SELECT * FROM `dede_sys_enum` WHERE egroup='$egroup' AND evalue LIKE '$topvalue.%%%' ORDER BY evalue DESC ");
if(!is_array($arr))
{
$disorder = $minid;
$evalue = $minid.'.001';
}
else
{
$disorder = $minid;
preg_match("#([0-9]{1,})\.([0-9]{1,})#", $arr['evalue'], $matchs);
$addvalue = $matchs[2] + 1;
$addvalue = sprintf("d", $addvalue);
$evalue = $matchs[1].'.'.$addvalue;

}
$sql = "INSERT INTO `dede_sys_enum`(`ename`,`evalue`,`egroup`,`disorder`,`issign`)
VALUES('$ename','$evalue','$egroup','$disorder','$issign'); ";
// echo $sql;exit;
$dsql->ExecuteNoneQuery($sql);
}
// echo $minid;
WriteEnumsCache($egroup);
ShowMsg("成功添加枚举分类！", $ENV_GOBACK_URL);
exit();
} else {
$minid = $topvalue;
$maxid = $topvalue + 500;
$enames = explode(',', $ename);
foreach($enames as $ename)
{
$arr = $dsql->GetOne("SELECT * FROM `dede_sys_enum` WHERE egroup='$egroup' AND evalue>$minid AND evalue<$maxid ORDER BY evalue DESC ");
if(!is_array($arr))
{
$disorder = $evalue = $minid+1;
}
else
{
$disorder = $arr['disorder']+1;
$evalue = $arr['evalue']+1;
}
$dsql->ExecuteNoneQuery("INSERT INTO `dede_sys_enum`(`ename`,`evalue`,`egroup`,`disorder`,`issign`)
VALUES('$ename','$evalue','$egroup','$disorder','$issign'); ");
}
WriteEnumsCache($egroup);
ShowMsg("成功添加枚举分类！", $ENV_GOBACK_URL);
exit();
}
}



替换为：

else if($action=='addenum_save')
{
if(empty($ename) || empty($egroup)) {
Showmsg("类别名称或组名称不能为空！","-1");
exit();
}
if($issign==1 || $topvalue==0)
{
$enames = explode(',', $ename);
foreach($enames as $ename)
{
$arr = $dsql->GetOne("Select * From `dede_sys_enum` where egroup='$egroup' And (evalue mod 500)=0 order by evalue desc ");

if(!is_array($arr)) $disorder = $evalue = ($issign==1 ? 1 : 500);
else $disorder = $evalue = $arr['disorder'] + ($issign==1 ? 1 : 500);

$dsql->ExecuteNoneQuery("Insert into `dede_sys_enum`(`ename`,`evalue`,`egroup`,`disorder`,`issign`)
values('$ename','$evalue','$egroup','$disorder','$issign'); ");
}
WriteEnumsCache($egroup);

ShowMsg("成功添加枚举分类！".$dsql->GetError(), $ENV_GOBACK_URL);
exit();
}
else
{
$minid = $topvalue;
$maxid = $topvalue + 500;
$enames = explode(',', $ename);
foreach($enames as $ename)
{
$arr = $dsql->GetOne("Select * From `dede_sys_enum` where egroup='$egroup' And evalue>$minid And evalue<$maxid order by evalue desc ");
if(!is_array($arr))
{
$disorder = $evalue = $minid+1;
}
else
{
$disorder = $arr['disorder']+1;
$evalue = $arr['evalue']+1;
}
$dsql->ExecuteNoneQuery("Insert into `dede_sys_enum`(`ename`,`evalue`,`egroup`,`disorder`,`issign`)
values('$ename','$evalue','$egroup','$disorder','$issign'); ");
}
WriteEnumsCache($egroup);
ShowMsg("成功添加枚举分类！", $ENV_GOBACK_URL);
exit();
}
}


然后保存，在系统后台更新系统缓存就可以了的。现在在后台的联动类别管理里面就可以增加二级选择了。