title: how to use first in IIF conditon Rdlc
body: <p>i am using four dataset for binding a rdlc, and for one text value i am using one dataset and use  below condition but this is working.</p>
  
  <pre><code>IIF(Fields!Str_BVN.Value is Nothing,"Not Verified","Verified")
  </code></pre>
  
  <p>But when i use two dataset and use below IIF condition this give me exception </p>
  
  <pre><code>First(IIF(Fields!Str_BVN.Value is Nothing,"Not Verified","Verified"),"DataSetGetPeople")
  </code></pre>
  
  <p>can you please tell me what i am doing mistake or what i need to do. Many solution that i found they are telling that try to use one dataset. But i really need to use four dataset for my report</p>
  
  <p><strong>Excretion</strong> </p>
  
  <pre><code>Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: The specified operation is not valid
  </code></pre>
  
  <p>Thanks for your reply and comments</p>