This question has been answered by Bruno17. See the first response.
params.resource_id = '[[+config.resource_id]]';
$gridfunctions['this.csvExport'] = "
csvExport: function(btn,e) {
var s = this.getStore();
var code, type, category, study_type, ebs_state;
var box = Ext.MessageBox.wait('Preparing ...', _('migx.export_current_view'));
var params = s.baseParams;
var o_action = params.action || '';
var o_processaction = params.processaction || '';
params.action = 'mgr/migxdb/process';
params.processaction = 'export';
params.configs = this.config.configs;
params.resource_id = '[[+config.resource_id]]';
MODx.Ajax.request({
url : this.config.url,
params: params,
listeners: {
'success': {fn:function(r) {
location.href = this.config.url+'?action=mgr/migxdb/process&processaction=export&download='+r.message+'&id='+id+'&HTTP_MODAUTH=' + MODx.siteId;
box.hide();
},scope:this}
}
});
params.action = o_action;
params.processaction = o_processaction;
return true;
}
";