title: How to save System.Media.DateEncoded in UWP video StorageFile
body: <p>For a given <code>StorageFile</code>, named file, I can retrieve some properties by calling</p>
  
  <pre><code>await file.Properties.RetrievePropertiesAsync(propertiesToRetrieve)
  </code></pre>
  
  <p>Change them and save them properly</p>
  
  <pre><code>await file.Properties.SaveProperties(propertiesToSave)
  </code></pre>
  
  <p>However, I am getting a <code>The method or operation is not implemented</code> error in a <code>try/catch</code> block whenever I try to save the <code>System.Media.DateEncoded</code> property to a video file (MP4 and MOV), but i can read them without problem.</p>
  
  <p>Is there a way to save such a property with the current API?</p>
  
  <p>Thank you</p>
  
  <p><strong>Added Info</strong></p>
  
  <p>The DateTimeOffset comes from a DatePicker combined with a Timepicker, and it is injected in in a function similar to the one below. To simplify the code, I use below a hardcoded value for the DateTimeOffset. The exception is still thrown with the same message. I guarantee on my side that file is not null (not shown).</p>
  
  <pre><code>    public async Task&lt;bool&gt; SaveDateEncoded(StorageFile file)
      {
          try
          {
              var dateTimeOffset = new DateTimeOffset(2000, 09, 03, 3, 50, 13, new TimeSpan(2, 0, 0));
              var props = new List&lt;KeyValuePair&lt;string, object&gt;&gt;()
              {
                          new KeyValuePair&lt;string, object&gt;("System.Media.DateEncoded",dateTimeOffset),
              };
              await file.Properties.SavePropertiesAsync(props);
              return true;
          }
          catch (Exception ex)
          {
  
              return false;
          }
      }
  </code></pre>