title: Mdx Using a member property as an argument for a strtomember
body: <p>I'm working on a cube that has two date dimensions, with the same structure, but measuring different behaviours: one measures the stay date, and the other one the reservation date. So I need to create a set that will isolate all reservations made for a specific date, until 1 year prior that specific date. I need the set to be dynamic, so it changes when the stay date changes...</p>
  
  <p>Now, I am blowing my mind off trying to undertand why this works fine:</p>
  
  <pre><code>SET [D365] AS {NULL: [Creation Date].[Calendar].[Day].&amp;[20131023].lag(365)}
  </code></pre>
  
  <p>But this does not:</p>
  
  <pre><code>SET [D365] AS {null:strtomember("[Creation Date].[Calendar].[Day].&amp;["+ [Business Date].[Calendar].currentmember.properties("Key")+"]").lag(365)}
  </code></pre>
  
  <p>when</p>
  
  <pre><code>MEMBER [Measures].[Arg] as [Business Date].[Calendar].currentmember.properties("Key")
  </code></pre>
  
  <p>returns : 20131023</p>
  
  <p>and </p>
  
  <pre><code>MEMBER [Measures].[Arg2] as "[Creation Date].[Calendar].[Day].&amp;["+[Business Date].[Calendar].currentmember.properties("Key")+"].lag(365)"
  </code></pre>
  
  <p>returns [Creation Date].[Calendar].[Day].&amp;[20131023].lag(365)</p>
  
  <p>I've also tried to use cstr and format ("yyyyMMdd") before the argument, but to no avail...</p>
  
  <p>Really, I am running out of ideas... :) </p>
  
  <p>Thanks a lot for your help.</p>