title: How to set default field values for add form in jqgrid from current row
body: <p>Add toolbar button is used to add new row to jqgrid. 
  Add form which appears contains all filed vlaues empty. 
  How to set add form field values from column values from row which was current/selected when add command was issued ?
  json remote data is used. Or if this is simpler, how to call server method passing current/selected row to retrieve default values for add form from server ?</p>
  
  <p>jqgrid contains also hidden columns. If possible values from hidden columns from current row should also sent to add controller if add form is saved.</p>
  
  <p><strong>Update</strong></p>
  
  <p>I tried to use Oleg great suggestion by using</p>
  
  <pre><code>         afterShowForm: function(formID) {
             var selRowData, 
                 rowid = grid.jqGrid('getGridParam', 'selrow');
             if (rowid === null) {
               // todo: how to cancel add command here
               alert('Please select row');
               return;
               }
  
             selRowData = grid.jqGrid('getRowData', rowid);
             if (selRowData === null) {
               alert('something unexpected happened');
               return;
               }
  
             $('#' + 'Baas' + '.FormElement', formID).val(selRowData.Baas);
             }
  </code></pre>
  
  <p>Application keeps add form open after saving. After first save Baas field is empty. It looks like afterShowForm event runs only once, not after every save. How to fix this so that multiple rows with default values can added without closing add form?
  How to cancel or not allow Add command if there is no selected row ?</p>