I recently posted a question about how to automatically select an item in
a grid which is being populated by an HTTP dataset. I tried a solution
posted by William Krick and this solution seemed to work. However, today
I was noticing that when my grid contained more elements than were
visible, the scroll bar didn't function correctly and I couldn't reliably
page through the grid. I also noticed that my code to select the first
item was being called multiple times when I would have only expected it to
have been called once. I suspect that the problem has to do with how I
had to change the implementation to work with a Grid, since William's
example was for a combobox. I'm hoping that someone can help me see the
error of my ways and offer a solution that works for grids.
Here is the code that I'm using:
<class name="mygrid" extends="grid"
<gridcolumn name="column1" ... >
...
</gridcolumn>
<gridcolumn name="column2" ... >
<text font="Arial" fontstyle="bold">
<datapath xpath="title/text()">
<method name="registerDelegate" args="v, event">
if ( this['dLastInit'] ) {
dLastInit.unregisterAll();
} else {
this.dLastInit = new
LzDelegate( parent.parent.parent, '_selectFirst' );
}
dLastInit.register( v, event );
</method>
<method args="clones" event="onclones">
registerDelegate( clones[clones.length-1], 'oninit' );
</method>
<method args="data" event="ondata">
registerDelegate( parent, 'ondata' );
</method>
</datapath>
<text>
</gridcolumn>
<gridcolumn name="column3" ... >
...
</gridcolumn>
<method name="_selectFirst">
Debug.write("Selecting first item");
selectItemAt(0);
</method>
</class>
I put the _selectFirst delegation code inside of one of the grid columns
since I didn't know where else to put it. It's on the second column
because I know that column will always have data. I instantiate on
instance of 'mygrid' in my app and associate it with a dataset. When the
data is retrieved, I see several 'Selecting first item' messages in the
debugger which tells me the _selectFirst method is being called multiple
times. This wouldn't be a major problem, but it seems that calling
selectItemAt(0) messes things up. I also notice that when I scroll the
grid, my _selectFirst method gets called. Perhaps this is what is messing
up scrolling since as I move down the page, I'm continually telling the
grid to selectItemAt(0). Can someone offer me some help on getting this
selection operation to work correctly for a grid component?
Thanks.
--
James Howe
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