title: Object reference not set to an instance of an object when using FindControl
body: <p>I am using the following code.</p>
  
  <p>.ascx file:</p>
  
  <pre><code>&lt;div class="DemoArea"&gt;
      &lt;asp:Button ID="btnCaseComplete" runat="server" Text="Case Complete" CssClass="btn_contentlist"
          onclick="btnCaseComplete_Click" OnClientClick="scroll(0,0);$.loading({mask: true, effect: 'ellipsis update'});"/&gt;
         &lt;ComponentArt:Dialog ID="caDropDownDialog" runat="server" Modal="true" Alignment="MiddleCentre" AllowDrag="true" AllowResize="false" AnimationDuration="1000" 
                              CloseTransition="Fade"  RenderOverWindowedObjects="true" ShowTransition="Fade" AnimationType="Outline" CssClass="ModalMask"&gt;
                              &lt;Header&gt;&lt;p class="header"&gt;Case Complete&lt;/p&gt;&lt;/Header&gt;
                              &lt;Content&gt;
                                  &lt;asp:Panel ID="panSelectArea" runat="server" CssClass="modalMaskContent"&gt;
  
                                     &lt;p&gt;&lt;span class="red"&gt;Please Note:&lt;/span&gt;Once you click
                                          &lt;span class="bold"&gt;Ok&lt;/span&gt;, your 
                                              case will be Submitted to ACR and you will not be able to edit the Case again. 
  
                                              &lt;span class="style2"&gt;To continue editing the case, click &lt;/span&gt;
                                              &lt;span class="bold"&gt;Cancel&lt;/span&gt;. You will be taken back 
                                              to the Case Wizard and your case will not be submitted to ACR.&lt;/p&gt;
                                    &lt;/asp:Panel&gt;
                              &lt;/Content&gt;
                              &lt;Footer&gt;
                                &lt;center class="modalMaskFooter"&gt;
                                      &lt;asp:Button ID="btnOK" runat="server" CausesValidation="false" 
                                          CssClass="btn_contentlist" OnClientClick="caDropDownDialog.IsShowing=false" Text="OK" /&gt;
                                      &lt;asp:Button ID="btnCancel" runat="server" CausesValidation="false" 
                                          CssClass="btn_contentlist" OnClientClick="caDropDownDialog.Close();" Text="Cancel" /&gt;
                                  &lt;/center&gt;
                              &lt;/Footer&gt;
                          &lt;/ComponentArt:Dialog&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>Code behind:</p>
  
  <pre><code>CaseContentList obj = new CaseContentList(); // creating the object of case content list control to this page
  
          LinkButton lbtn = (LinkButton)((DataList)obj.FindControl("dlstContentList")).FindControl("lbtnDisplay");
          if (lbtn.Text == "Final Page")
          {
              caDropDownDialog.IsShowing = true;
          }
          else
              Page.ClientScript.RegisterStartupScript(this.GetType(), "Window", "alert('Add Final Page First.');", true);
  </code></pre>
  
  <p>But it's giving an error 'object reference not set to an instance of an object'.</p>