Passing extra data to jqGrid

I've been trying to figure out how to pass additional information when adding a new record to my jqGrid. I've checked here, here, here, and here just to list a few. All pretty much say the same thing. I should be able to use editData to pass additional info.

Here are my add parameters:

    addSettings = {                                     
        recreateForm: true,
        width: 400,
        mtype: "POST",                                  
        jqModal: true,
        reloadAfterSubmit: false,
        savekey: [true, 13],
        closeOnEscape: true,
        closeAfterAdd: true,
        editData: { SomeExtraData: function () { return $('#header_id').val(); } },
        onclickSubmit: onclickSubmitLocal
      };

The record that I'm trying to add is a detail record and it has to have the id from the header; ie header_id. When I check the data that is being sent to the web service I don't see any addit开发者_开发技巧ional information.

    [WebInvoke(Method = "POST", UriTemplate = "/Save/AddDetail", BodyStyle = WebMessageBodyStyle.Wrapped, RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
    public string AddDetail(string Id, string Step_Number, string Step_Description, string oper, string id)

I've tried putting an additional parameter in my web service but it always is undefined. I've tried returning just a string value, one that isn't obtained, and it's the same thing.

Thank you again for any help and assistance.

I suppose that you have the problem in the part of your code which you don't posted here. I suppose that you use JSON.stringify inside of serializeRowData. The JSON.stringify don't execute methods of editData. Se you should modify your implementation of serializeRowData like I described here or originally for the postData here.