ExtJS how to build linkage comboboxes in Grid panel

Question

I'm new to ExtJS and I'm working on a address book in which admins can edit the users' address by pick the listed states and cities from two combobox.

I need to build some linkage comboboxes in grid panel so that after admin pick one state in the first drop-down, the relatives cities will be listed in the second drop-down automatically.

If it's only a simple panel I can update the cityStore after state been selected with following code:

        {                               
            xtype:"combo",                                                                                   
            name:'state',  
            id:'state',  
            displayField:'name',  
            valueField:'id',  
            store:storeState,  
            triggerAction:'all',  
            queryMode:'local',  
            selecOnFocus:true,  
            forceSelection:true,  
            allowBlank:false,  
            editable:true,
            //using select listener for updating city store  
            listeners:{  
                select:function(combo,record,index){  
                    try{  
                        var city = Ext.getCmp('city');  
                        city.clearValue();  
                        city.store.load(  
                             {  
                                 params:{  
                                     paramId:combo.getValue()  
                                 }  
                             }     
                        );  
                    }catch(ex){  
                        alert("Failed to load data");  
                    }  

                }  
                }  

        },

However in GridPanel if I update the cityStore with same way, the whole column will changed. Is there anyway to only address the column in the same row in Grid panel? Thanks!

Answer 1

You need to use validateedit & beforeedit events of grid to update the city store.

listeners: {
        validateedit: {  // to check if state value is changed & clearing city value
                fn: function(event,editor){ 
                    switch (editor.field) {
            case 'state':
                 if(editor.value!=editor.record.getData().state)
                     editor.record.set('city',null);
                break;
             }
        return true;
        }
        },
        beforeedit: { // to update the city store based the state value of corresponding row
                fn: function(event,editor){                   

        switch (editor.field) {
            case 'city':
                  var cityStore = Ext.data.StoreManager.lookup('cityStore');
                 cityStore.load({  
                                  params:{  
                                         paramId:editor.value 
                                         }  
                                   });  
                 break;
                }
         return true;
         }
        }
       }

Here is a working example where i am using two local stores state & city. Filtering the city store whenever it is edited with the value of state given in same row.There are three states A,B,C with 1-5,6-10 & 11-15 cities respectively.

Answer 2

You just need to reload Cities store with param from State every time user clicks on a City editor. Do it in beforequery event in combobox.

{
    //this is your Cities combo
    xtype: 'combo',
    valueField: 'foo',
    displayField: 'bar',
    queryMode: 'remote',
    queryCaching: false, //don't forget to disable query caching        
    bind: {
        store: '{cities}',   
    },
    listeners: {
        beforequery: function(queryPlan) {
            //get param from your States store
            queryPlan.combo.getStore();
            //then load this store
        }
    }
}