Create a Rails-based Excel Clone with jqGrid : Page 2

         var mygrid = jQuery("#fact").jqGrid({ 
url:'/facts?q=1', 
editurl:'/facts/update', 
datatype: "json", 
colNames:['ID','NAME'], 
colModel:[{name:'id', index:'id',resizable:false,width:135, editable:false },{name:'NAME', index:'NAME',edittype:'text',editable:true}], 
pager: '#fact_pager', 
rowNum:$row_num, 
rowList:$no_elem, 
imgpath: '/images/jqgrid', 
sortname: '', 
viewrecords: true, 
height:$table_height, 
width: $table_width, 
sortorder: '', 
gridview: false, 
scrollrows: true, 
autoheight: false, 
autowidth: false, 
rownumbers: false, 
multiselect: true, 
subGrid: true, 
....
....

Note the multiselect field is highlighted and set to true. This field creates (enables) the checkboxes as shown in the Figure 4 below.

Click here for larger image
Figure 4. Checkboxes Enables

The user can select the rows by either clicking on that particular row or by clicking the checkbox. JqGrid takes care of the editing of the fields. By clicking the "edit" [pencil] icon at the bottom of the table, users can traverse through the fields of each row and edit the values. This is very similar to what was discussed in the previous section. In Figure 5 below, the row containing the value "COST" has been selected.

Click here for larger image
Figure 5. Row Containing "COST" Has Been Selected

One of the important features that a user typically expects with multiselect is deletion. For any deletion to happen, users have to fetch the ID or the rows that need to be passed to the backend for deletion.

     ondblClickRow: function(id) { 
if (id) { var grid = jQuery('#fact'); 
    if(id != prev) { grid.saveRow(prev);
                     grid.editRow(id, true);
                        prev = id; } 
    else { prev = -1; 
           grid.saveRow(prev); } } }, 


     onSelectRow: function(id) {
                        var gr = jQuery("#fact").getGridParam('selarrrow');
              },

     onKeyup: function(id){
                      grid.saveRow(id);
              },

JqGrid allows users to fetch the selected rows and the contents using the onSelectRow function. The values within the grid can be fetched using getGridParam. Note the selarrrow parameter to getGridParam. That is not misspelled; it is indeed 'sel' + 'arr' + 'row'. Selarrrow returns an array of IDs of all the fetched IDs.

The backend controller code includes the code for deletion. In the destroy method of the controller class, all the IDs that were marked for deletion are fetched from the params[:id] parameter.

  def post_data
          if params[:oper] == "del"
            destroy
          else
            @fact = { :id => params[:id], :NAME => params[:NAME], :TYPE => params[:TYPE] }
            if params[:id] == "_empty"
              create
            else
              Fact.find(params[:id]).update_attributes(@fact)
            end
          end
          render :nothing => true
  end


  # DELETE /facts/1
  # DELETE /facts/1.xml
  def destroy

    ids = params[:id].split(",");

    @facts = Fact.find(ids)

    if(@facts.nil?)
        puts "**********************"
        puts "No item found for deletion"
        puts "**********************"
    end

    @facts.each do |fact|
        fact.destroy
    end

    @facts = Fact.find(:all, :limit => params[:rows],
                                                :offset => (params[:page].to_i - 1) * params[:rows].to_i);

  end
end

Selarrrow may sound a bit weird and at times users may want to select the ID of just one row. For that, getGridParam('selrow') returns the ID of the presently selected row. You can look into jqGrid's getGridParam documentation for more details on the other methods that are available.

In upcoming articles in this series, the focus will be on selecting and using multiple rows in jqGrid.