title: Zk get value of child component mvvm
body: <p>Include component value showing null Not binding.</p>
  
  <pre><code>&lt;window id="win" width="100%" border="normal" height="100%"
      apply="org.zkoss.bind.BindComposer" validationMessages="@id('vmsgs')"
      viewModel="@id('vm') @init('com.customer.portal.controller.MotorQuotationViewModel')"&gt;
  
  &lt;row&gt;
       &lt;include src="basicInfo.zul"&gt;&lt;/include&gt;
  &lt;/row&gt;
  &lt;row&gt;
       &lt;button id="btnCalculatePremium"
                          onClick="@command('calculatePremium')" /&gt;
  &lt;/row&gt;
  </code></pre>
  
  <p>basicInfo.zul</p>
  
  <pre><code>&lt;window id="win" width="100%" border="normal" height="100%"
          apply="org.zkoss.bind.BindComposer" validationMessages="@id('vmsgs')"
          viewModel="@id('vm') @init('com.customer.portal.controller.BaseController')"&gt;
          &lt;grid&gt;
              &lt;rows&gt;
                  &lt;row&gt;
                      &lt;label id="lblBasicInfo"&gt;&lt;/label&gt;
                  &lt;/row&gt;
                  &lt;row id="rowIdType"&gt;
                      &lt;label id="lblIdType"&gt;&lt;/label&gt;
                      &lt;textbox id="txtIdType" inplace="true"
                          value="@bind(vm.riskWebVO.VName)" constraint="no empty" /&gt;
                  &lt;/row&gt;
  &lt;/rows&gt;
  &lt;/grid&gt;
  &lt;/window&gt;
  </code></pre>
  
  <p>Main View Model</p>
  
  <pre><code>public class MotorQuotationViewModel extends BaseController {
  
      public void calculatePremium() {
  logger.info(riskWebVO.getVName());//Showing null
  
  }
  public UwmtRiskWebVO getRiskWebVO() {
          return riskWebVO;
      }
  
      public void setRiskWebVO(UwmtRiskWebVO riskWebVO) {
          this.riskWebVO = riskWebVO;
      }
  
  }
  </code></pre>
  
  <p>Child view model</p>
  
  <pre><code>    public class BaseController extends SelectorComposer&lt;Component&gt;{ 
          protected UwmtRiskWebVO riskWebVO = new UwmtRiskWebVO();
      public UwmtRiskWebVO getRiskWebVO() {
              return riskWebVO;
          }
  
          public void setRiskWebVO(UwmtRiskWebVO riskWebVO) {
              this.riskWebVO = riskWebVO;
          }
  
      }
  </code></pre>
  
  <p>When I'm getting value of main view model it's binding the values but when i'm trying to get the values of include components its showing null.</p>