Deleting item from Sharepoint calendar -

i want delete item sharepoint calendar. here part of code:

                microsoft.sharepoint.client.camlquery query = new microsoft.sharepoint.client.camlquery();                 query.viewxml = "<view><query><where><and><eq><fieldref name='title'/><value type='text'>"                      + requesttitle +                     "</value></eq><eq><fieldref name='eventdate'/><value type='text'>"                     + lfrom +                     "</value></eq></and><and><eq><fieldref name='enddate'/><value type='text'>"                     + lto +                     "</value></eq><eq><fieldref name='falldayevent'/><value type='text'>"                     + boolean.truestring +                     "</value></eq></and></where></query></view>";                  microsoft.sharepoint.client.listitemcollection listitem = calendar.getitems(query);                 context.load(listitem);                 if (listitem.count == 1)                 {                     listitem[0].deleteobject();                     //context.executequery();                 } 

it throws exception in line

               if (listitem.count == 1) 

it says listitem not initialized. throws exception when pass empty query this:

               microsoft.sharepoint.client.listitemcollection listitem = calendar.getitems(new microsoft.sharepoint.client.camlquery()); 

why? on link https://msdn.microsoft.com/en-us/library/office/ee534956(v=office.14).aspx said should retrieve items when empty query passed.

evertyhing works adding new item calendar, here code used that:

                //adding new calendar item                 microsoft.sharepoint.client.listitemcreationinformation item = new microsoft.sharepoint.client.listitemcreationinformation();                 microsoft.sharepoint.client.listitem newitem = calendar.additem(item);                 newitem["title"] = requesttitle;                 newitem["eventdate"] = lfrom;                 newitem["enddate"] = lto;                 newitem["falldayevent"] = boolean.truestring;                 newitem.update(); 

since, have used,

microsoft.sharepoint.client

library, assuming client-side application. in client-side app, sending request server costly affair. hence, happens whenever load component, request created in background. way, can bundle multiple request 1 using load() many times. send request server, need call executequery() before checking length of listitemcollection.

microsoft.sharepoint.client.listitemcollection listitem = calendar.getitems(query); context.load(listitem);  context.executequery(); // take while  if (listitem.count == 1) {     listitem[0].deleteobject();     context.executequery(); }