ArcGis javascript api 3.5 how to set visibility of a feature layer - arcgis

Question

i am using ArcGis javascript api 3.5 and my code is
map = new esri.Map("mapDiv", {
basemap: "streets",
center: [-112.07102547942392, 46.75909704205151],
zoom: 12,
slider: false,
infoWindow: infoWindow
});
var featureLayer = new esri.layers.FeatureLayer("http:/abc/arcgis/rest/services/MTARNG/MapServer/1", {
mode: esri.layers.FeatureLayer.MODE_SNAPSHOT,
infoTemplate: templateFuze,
outFields: ["*"]
});
var featureLayer1 = new esri.layers.FeatureLayer("http://abc/arcgis/rest/services/MTARNG/MapServer/0", {
mode: esri.layers.FeatureLayer.MODE_SNAPSHOT,
infoTemplate: templateParcel,
outFields: ["*"]
});
var featureLayer2 = new esri.layers.FeatureLayer("http://abc/arcgis/rest/services/MTARNG/MapServer/2", {
mode: esri.layers.FeatureLayer.MODE_SNAPSHOT,
infoTemplate: templateGrid,
outFields: ["*"]
});
Ext.create('Ext.form.Panel', {
width: 400,
height: 600,
bodyPadding: 10,
renderTo: Ext.get('LayerDiv'),
items: [{
xtype: 'checkboxgroup',
columns: 1,
vertical: true,
items: layerInfo,
listeners: {
change: {
fn: function (checkbox, checked) {
for (var i = 0; i < checkbox.items.items.length; i++) {
if (checkbox.items.items[i].checked) {
//visible true checkbox.items.items[0].boxLabel
}
else {
//visible false
}
}
}
}
}
}]
});
});
So i am trying to set the visibilty of the layer but i am not able to do. after that how to refresh the map ?
I got some function but it is working e.g.- visibleAtMapScale = false,
defaultVisibility = false and for refreshing i got only map.resize=true;
What else i can try to achive this functionality.

Answer 1

You can change the visibility of an layer using the hide() and show() functions - FeatureLayer inherits them from GraphicsLayuer (Which inherits them from Layer). So in your example, given featureLayer is a global variable it should be in scope when the event fires so you could just do:
featureLayer.hide();
and
featureLayer.show();
You don't need to refresh the map, it will happen automatically.
Simon

Answer 2

When creating a new FeatureLayer, you can specify the default visibility using the optional parameters. The default is true.
var featureLayer = new esri.layers.FeatureLayer("http:/.../MapServer/1",
{visible:false}
});
To set the visibility of the existing layer, you can use the setVisibility() method.
featureLayer.setVisibility(false);

Answer 3

If you want to enable intellisense support in Visual Studio you can download and reference the code assist plugin from the Esri website. There is a help page about it here with links to the various versions supported and how to use it from VS.
If you just want to get the VS2012 version for v3.5 of the JS API it is here and to reference it:
If working in an HTML file, add a script tag to add a reference to the code assist
<script type='text/javascript' src='path_to_vsdoc.js'></script>
If working in a JavaScript file, add a reference directive to the VSDoc file:
/// <reference path="~/Scripts/esri-jsapi-vsdoc.js" />