# GeoExt

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- `GeoExt.tree.LayerParamLoader`

# `GeoExt.tree.LayerParamLoader`

Extends
  - Ext.util.Observable

class `GeoExt.tree.``LayerParamLoader`
  A loader that creates children from its node’s layer (`OpenLayers.Layer.HTTPRequest`) by items in one of the values in the layer’s params object.

## Config Options

Configuration properties in addition to those listed for Ext.util.Observable.

`delimiter`
  `String` Delimiter of the `param`‘s value’s items. Default is `,` (comma). If the `param`‘s value is an array, this property has no effect.

`param`
  `String` Key for a param (key-value pair in the params object of the layer) that this loader uses to create childnodes from its items. The value can either be an `Array` or a `String`, delimited by the character (or string) provided as `delimiter` config option.

## Public Methods

Public methods in addition to those listed for Ext.util.Observable.

`LayerParamLoader.``createNode`()

  Parameter: | attr – `Object` attributes for the new node

  Override this function for custom TreeNode node implementation, or to modify the attributes at creation time.

## Events

Events in addition to those listed for Ext.util.Observable.

`beforeload`

  Triggered before loading children. Return false to avoid loading children.

  Listener arguments:

  - loader - `GeoExt.tree.LayerLoader` this loader

  - node - `Ex.tree.TreeNode` the node that this loader is

      configured with

`load`

  Triggered after children were loaded.

  Listener arguments:

  - loader - `GeoExt.tree.LayerLoader` this loader

  - node - `Ex.tree.TreeNode` the node that this loader is

      configured with

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