XPages. Hide column in DataTable - datatable

Question

I'm trying to hide a column in the dataTable, but not working. Hiding only header. In example I try hide first column. Domino 9.0.1.
I was mistaken or is it a bug?
I know about the "display: none" for the column, but I have a lot of data, and not rendered column save my local performance
<xp:dataTable id="dataTable1" rows="30" var="item">
<xp:this.value><![CDATA[#{javascript:var collection = [];
for( var i = 0; i < 10; i++ ) {
var obj = {};
obj.name = "Name" + i;
obj.key = "Key" + i;
collection.push( obj );
}
return collection;}]]></xp:this.value>
<xp:column id="column1" rendered="false">
<xp:this.facets>
<xp:span xp:key="header">Name</xp:span>
</xp:this.facets>
<xp:text escape="true" id="computedField1"
value="#{item.name}">
</xp:text>
</xp:column>
<xp:column id="column2">
<xp:this.facets>
<xp:span xp:key="header">Key</xp:span>
</xp:this.facets>
<xp:text escape="true" id="computedField2" value="#{item.key}"></xp:text>
</xp:column>
</xp:dataTable>

Answer 1

I can confirm I get exactly the same behavior out of this. I agree that I would expect the entire column to not render, but that's apparently not its behavior. I've always viewed the xp:dataTable control as a slightly dressed up xp:repeat, but not with as much window dressing as an xp:viewPanel control and the Domino Designer wiki page on xp:dataTable isn't exactly helpful for any of the specifics and my Mastering XPages 2nd ed. also doesn't go too far into detail on xp:dataTable.
It's also worth noting that also setting the rendered property on your xp:text field still builds out the first cell in each row, regardless of the first <th> being suppressed. I'm guessing there's something in the way the xp:dataTable control builds out the HTML elements that's funky.
My recommendation would be to switch to an xp:repeat control, which will give you more control over the entire process. Adapting your code, it would go somewhat like this:
<xp:table>
<xp:tr>
<xp:td>Name</xp:td>
<xp:td>Key</xp:td>
</xp:tr>
<xp:repeat
id="repeat1"
rows="30"
var="item">
<xp:this.value><![CDATA[#{javascript:var collection = [];
for( var i = 0; i < 10; i++ ) {
var obj = {};
obj.name = "Name" + i;
obj.key = "Key" + i;
collection.push( obj );
}
return collection;}]]></xp:this.value>
<xp:tr>
<xp:td
rendered="false">
<xp:text
escape="true"
id="computedField1"
value="#{item.name}">
</xp:text>
</xp:td>
<xp:td>
<xp:text
escape="true"
id="computedField2"
value="#{item.key}">
</xp:text>
</xp:td>
</xp:tr>
</xp:repeat>
</xp:table>
Do note that to also set the rendering property of the cell being used as the header label (in place of a <th> it will render as a <td>), you'll need to manage that property visibility separately.