jqGrid need a field editable on Add dialog but not Edit dialog

It seems to me that the answer to your question you will find here and here (look at the example also).

UPDATED: I don’t know commertial version of jqGrid. If you don’t solve your prblem you should post your question better in the forum http://www.trirand.net/forum/default.aspx.

If I understand your code correct you can try to remove definition of the attributes readonly and disabled (JQGridEditFieldAttribute) from the EditFieldAttributes. Instead of that you can try to do following

If you want to show readonly fields ‘username’ and ‘domain’ in the edit dialog you can do following

jQuery("#myGrid").jqGrid('navGrid','#myGrid-pager',
                         { }, //options
                         { recreateForm: true, // edit options
                           beforeShowForm: function(form) {
                               $('#username',form).attr('readonly','readonly');
                               $('#domain',form).attr('readonly','readonly');
                           }
                         });

or without the usage of recreateForm: true option:

jQuery("#myGrid").jqGrid('navGrid','#myGrid-pager',
                         { }, //options
                         { // edit options
                           beforeShowForm: function(form) {
                               $('#username',form).attr('readonly','readonly');
                               $('#domain',form).attr('readonly','readonly');
                           }
                         },
                         { // add options
                           beforeShowForm: function(frm) {
                               $('#username',form).removeAttr('readonly');
                               $('#domain',form).removeAttr('readonly');
                           }
                         });

If you want not to show the fields ‘username’ and ‘domain’ in the edit dialog you can do

jQuery("#myGrid").jqGrid('navGrid','#myGrid-pager',
                         { }, //options
                         { recreateForm: true, // edit options
                           beforeShowForm: function(form) {
                               $('#username',form).hide();
                               $('#domain',form).hide();
                           }
                         });

It should work in the free version of the jqGrd, but because you use SetUpGrid which setup ome settings of jqGrid navigation bar (like grid.ToolBarSettings.ShowEditButton = true). You use also

grid.ClientSideEvents.GridInitialized = "initGrid"

I am not sure what you can do inside of initGrid function. Probably you should define some additional callbackes instead of calling of jQuery("#myGrid").jqGrid('navGrid', ...);. Look at http://www.trirand.net/documentation/aspnet/_2s20v9uux.htm and http://www.trirand.com/blog/phpjqgrid/docs/jqGrid/jqGridRender.html#methodsetNavOptions