Why Does My ASP.NET MVC jqGrid Dropdown Show an 'Undefined' Value?
Jan 11, 2025 am 08:45 AMResolving the "undefined" Value in ASP.NET MVC jqGrid Dropdowns
When dynamically populating jqGrid dropdowns during data editing, an unwanted "undefined" value frequently appears. This stems from inconsistencies between the data structure jqGrid expects and the data delivery method.
Correct jqGrid Data Format:
The ideal format for the dropdown's value is: value: "FE:FedEx; IN:InTime; TN:TNT"
Problem with Current Method:
The current approach uses ASP.NET MVC with jQuery's $.ajax()
to fetch dropdown data. A StringBuilder
manipulates the retrieved data to match jqGrid's format, but an extra "undefined" entry persists.
Debugging Findings:
FireBug debugging indicates that extra quotes introduced by sb.ToString()
are the culprit. jqGrid adds its own quotes, leading to doubled-up quotes and the "undefined" issue.
A Superior Solution: Using dataUrl
and buildSelect
Instead of directly manipulating the value
property, a more robust solution involves using jqGrid's dataUrl
and buildSelect
properties within editoptions
or searchoptions
. These allow for customized data fetching and formatting.
Example dataUrl
Action:
public JsonResult GetDestinationList() { List<string> allDestinations = GetAllDestinations(); return Json(allDestinations, JsonRequestBehavior.AllowGet); }
Example buildSelect
Function:
buildSelect: function(data) { var s = ''; if (data && data.length) { for (var i = 0, l = data.length; i < l; i++) { s += data[i] + ';'; // Assuming data[i] is already in "key:value" format } return s.substring(0, s.length - 1); // Remove trailing semicolon } return s; }
Updated editoptions
:
{ name: 'destinations', editable: true, edittype: 'select', editoptions: { dataUrl: '/YourController/GetDestinationList', // Replace with your controller action path buildSelect: function(data) { // ... (buildSelect function from above) ... } } }
Important Notes:
- You can use
Json(allDestinations);
withoutJsonRequestBehavior.AllowGet
, but you'll need to addajaxSelectOptions: { type: "POST" }
to your jqGrid options. - In newer jqGrid versions,
buildSelect
is called within the$.ajax()
success handler, makingjQuery.parseJSON(data.responseText)
unnecessary.
This revised approach provides a cleaner, more efficient, and less error-prone method for managing jqGrid dropdowns, eliminating the "undefined" value issue. Remember to replace /YourController/GetDestinationList
with the actual path to your controller action.
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