DHTMLX Docs & Samples Explorer

Formatting/Changing Data before Loading

Base Formatting Methods

In case you need to update values which were returned from database table or set some specific formatting before sending them to client side, you can use the “beforeRender” event handler.

Common use-case will be similar to next

        class RenderBehavior extends ConnectorBehavior{
	    public void beforeRender(DataItem data) {
                if (data->get_index() % 2 == 1 )
                       data.set_row_color("red");
	    } 
        }
 
	grid = new GridConnector(res);
	grid.event.attach(new RenderBehavior());
	grid.render_table("grid50000","item_id","item_nm,item_cd");

Here , color_rows function attached to the beforeRender event and set colors for rows based on their index.

During data generation, for each record outputed for client side beforeRender event will be executed, which means color_rows function will be called for each record. data is an instance of GridDataItem object, related to current record.

Same approach can be used for data formating

        class RenderBehavior extends ConnectorBehavior{
	    public void beforeRender(DataItem data) {
                String field = data.get_value("some");
                data.set_value("some","<a href='details.php?id="+field+"'>"+Details+"</a>");
	    } 
        }
 
	grid = new GridConnector(res);
	grid.event.attach(new RenderBehavior());

get_value and set_value method allow get or set value of any field related to the record ( it not affect actual values in DB ), if alias was used during data configuration - you need to use it instead of real db field name as first parameter of get|set command.

More complex formating rules can be defined by using “extra” fields in configuration, fields which will not be outputted to client but can be used inside events.

        class RenderBehavior extends ConnectorBehavior{
	    public void beforeRender(DataItem data) {
                //set row color
                data.set_row_color(data.get_value("color"));
                //save in userdata 
                $data.set_user_data("some_data",data.get_value("count"));
	    } 
        }
 
	grid = new GridConnector(res);
	grid.event.attach(new RenderBehavior());
	grid.render_table("grid50000","item_id","item_nm,item_cd","color,count");

Here, field color not outputted to client side , but used to define property of row. During update|insert operation only name and price columns may be changed, color will stay untouched. Count field will be sent to client side as userdata of the row ( and it will be possible to access it on client side through related data.

Formatting in Combo

In case of dhtmlxCombo event works the same but provides ComboDataItem as parameter of event, it possible to implement the same use-cases with it

Formatting in TreeGrid and Tree

TreeGrid provides TreeGridDataItem and Tree provides TreeDataItem for beforeUpdate event, both of them support base operations and few specific ones.

        class RenderBehavior extends ConnectorBehavior{
	    public void beforeRender(DataItem data) {
                TreeDataItem item = (TreeDataItem)data;
                if (item.get_value("complete").equals("75"))
                    item.set_check_state(true);
 
                if (item.get_value("duration").equals("10"))
                    item.set_image("true.gif");
                else
                    item.set_image("false.gif");
	    } 
        }
 
	tree.event.attach(new RenderBehavior());
  • set_image method allows to set image of tree element ( for treegrid it accepts only one parameter, while for tree it can be a single image of 3 different images for 3 states of tree's item.
  • set_check method exists only in TreeDataItem object and allow to set state of related checkbox ( tree need to have checkboxes enabled in js. configuration code as well )

beforeRender event can be used in dynamic Tree and TreeGrid to define which elements of hierarchy are branches and which are leafs. It is covered in related section of document.