Question

Can anyone please tell me the XML structure for sub-items that jqgrid uses. I’ve read the documentation and it does not explain clearly how one would create a tree view with sub-items in it. Basically I have a 2 column grid with 3 levels.

Answer 1

From the demo:
http://www.trirand.com/jqgrid35/jqgrid.html

(under new in version 3.3->tree grid)

It makes this ajax call as a post:
http://www.trirand.com/jqgrid35/server.php?q=tree

The post parameters looks like:

_search: false
n_left: 1
n_level: 0
n_right: 8
nd: 1241000465087
nodeid: 1
page: 1
rows: 20
sidx    
sord: asc

Which returns exactly this:

<?xml version='1.0' encoding='utf-8'?>
<rows>
<page>1</page>
<total>1</total>
<records>1</records>
<row><cell>1</cell><cell>Cash</cell><cell>100</cell><cell>400.00</cell<cell>250.00</cell><cell>150.00</cell><cell>0</cell><cell>1</cell><cell>8</cell><cell>false</cell><cell>false</cell></row>
<row><cell>5</cell><cell>Bank's</cell><cell>200</cell><cell>1500.00</cell><cell>1000.00</cell><cell>500.00</cell><cell>0</cell><cell>9</cell><cell>14</cell><cell>false</cell><cell>false</cell></row>
<row><cell>8</cell><cell>Fixed asset</cell><cell>300</cell><cell>0.00</cell<cell>1000.00</cell><cell>-1000.00</cell><cell>0</cell><cell>15</cell><cell>16</cell><cell>true</cell><cell>false</cell></row>
</rows>

For each sub row it makes another ajax call. The first “cell” element specifie the row number. When there is a gap before the next row id, it knows that it has subitems, and will put an expander for that row. When the user selects the expander, it makes another ajax call, and the following is returned:

<?xml version='1.0' encoding='utf-8'?>
<rows>
<page>1</page>
<total>1</total>
<records>1</records>
<row><cell>2</cell><cell>Cash 1</cell><cell>1</cell><cell>300.00</cell><cell>200.00</cell><cell>100.00</cell><cell>1</cell><cell>2</cell><cell>5</cell><cell>false</cell><cell>false</cell></row>
<row><cell>4</cell><cell>Cash 2</cell><cell>2</cell><cell>100.00</cell><cell>50.00</cell><cell>50.00</cell><cell>1</cell><cell>6</cell><cell>7</cell><cell>true</cell><cell>false</cell></row>
</rows>

Looking at the source, it specifies column names, and it’s expecting them to be returned in order. I’m pretty sure you can write this to not expect a particular order, but that’s how the mapping is set. This is pretty much a clone of the way ext does things, which is a good way to follow because they do it well.

jQuery("#treegrid").jqGrid({
    url: 'server.php?q=tree',
    treedatatype: "xml",
    mtype: "POST",
    colNames:["id","Account","Acc Num", "Debit", "Credit","Balance"],
    colModel:[
        {name:'id',index:'id', width:1,hidden:true,key:true},
        {name:'name',index:'name', width:180},
        {name:'num',index:'acc_num', width:80, align:"center"},
        {name:'debit',index:'debit', width:80, align:"right"},      
        {name:'credit',index:'credit', width:80,align:"right"},     
        {name:'balance',index:'balance', width:80,align:"right"}        
    ],
    height:'auto',
    pager : jQuery("#ptreegrid"),
    imgpath: gridimgpath,
    treeGrid: true,
    ExpandColumn : 'name',
    caption: "Treegrid example"
});

And, for completeness, lets include the PHP source example (went through this much trouble, might as well finish it off!):

$node = (integer)$_REQUEST["nodeid"];
// detect if here we post the data from allready loaded tree
// we can make here other checks
if( $node >0) {
    $n_lft = (integer)$_REQUEST["n_left"];
    $n_rgt = (integer)$_REQUEST["n_right"];
    $n_lvl = (integer)$_REQUEST["n_level"];

    $n_lvl = $n_lvl+1;
    $SQL = "SELECT account_id, name, acc_num, debit, credit, balance, level, lft, rgt FROM accounts WHERE lft > ".$n_lft." AND rgt < ".$n_rgt." AND level = ".$n_lvl." ORDER BY lft";
} else { 
    // initial grid
    $SQL = "SELECT account_id, name, acc_num, debit, credit, balance, level, lft, rgt FROM accounts WHERE level=0 ORDER BY lft";
}
$result = mysql_query( $SQL ) or die("Couldn t execute query.".mysql_error());
if ( stristr($_SERVER["HTTP_ACCEPT"],"application/xhtml+xml") ) {
header("Content-type: application/xhtml+xml;charset=utf-8"); } else {
header("Content-type: text/xml;charset=utf-8");
}
$et = ">";
echo "<?xml version='1.0' encoding='utf-8'?$et\n";
   echo "<rows>";
echo "<page>1</page>";
echo "<total>1</total>";
echo "<records>1</records>";
// be sure to put text data in CDATA
while($row = mysql_fetch_array($result,MYSQL_ASSOC)) {
    echo "<row>";           
    echo "<cell>". $row[account_id]."</cell>";
    echo "<cell>". $row[name]."</cell>";
    echo "<cell>". $row[acc_num]."</cell>";
    echo "<cell>". $row[debit]."</cell>";
    echo "<cell>". $row[credit]."</cell>";
    echo "<cell>". $row[balance]."</cell>";
    echo "<cell>". $row[level]."</cell>";
    echo "<cell>". $row[lft]."</cell>";
    echo "<cell>". $row[rgt]."</cell>";
    if($row[rgt] == $row[lft]+1) $leaf = 'true';else $leaf='false';
    echo "<cell>".$leaf."</cell>";
    echo "<cell>false</cell>";
    echo "</row>";
}
echo "</rows>";