validate jqgrid data on the server, callback function - jqgrid

Question

I am using autocomplete in a textbox on my jqgrid. But i should not allow the user to select the same item twice. Because of pagination he wont see all data all times. Is there a way that on sending new row to server check for duplicate data in the server and send a status back to jqgrid maybe poping up an alert sayign "row already exist on table". What would be the bst approach to do this validation and notify the user? thanks.
$("#assessmentproduct").jqGrid({
url: 'orthofixServices.asmx/GetProductList',
colNames: ['id', 'Product Description', 'Commission Rate'],
colModel: [
{ name: 'id', hidden: true },
{ name: 'description', index: 'desc', width: 320, editable: true },
{ name: 'commissionrate', index: 'com', width: 120, editable: true, unformat: percentUnFormatter, formatter: percentFormatter, editrules: { number: true} }
],
serializeRowData: function(data) {
var params = new Object();
params.id = 0;
params.prdid = $("#prdid").val();
params.description = data.description;
params.commissionrate = data.commissionrate;
var result = JSON.stringify({ 'passformvalue': params, 'oper': data.oper, 'id': data.id });
return result;
},
mtype: "POST",
rowNum: 4,
height: 93,
width: 400,
pager: '#assessmentpager',
editurl: "orthofixServices.asmx/ModifyProductList"
});
$("#assessmentproduct").jqGrid('navGrid', '#assessmentpager', { add: false, edit: false, del: true, refresh: false, search: false }, {}, {}, { serializeDelData: function(postData) {
return JSON.stringify({ 'passformvalue': null, 'oper': postData.oper, 'id': postData.id });
}
});
$("#assessmentproduct").jqGrid('inlineNav', '#assessmentpager', { addParams: { position: "last", addRowParams: {
"errorfunc": duplicateRow, "aftersavefunc": function() { var grid = $("#assessmentproduct"); reloadgrid(grid); }
}
}, editParams: { "aftersavefunc": function() { var grid = $("#assessmentproduct"); reloadgrid(grid); } }
});

Answer 1

You should just hold the simple rule: if an error occur on the server (for example because of validation error) the server response should contains some error HTTP status code. In the case error message will be displayed to the user.
The exact error processing and the displayed error message format depends from the editing mode which you use. In case of inline editing I would recommend you to use errorfunc and restoreAfterError parameters of the editRow method. In case of form editing the errorTextFormat callback can be very helpful.