THIS WORKS! .. but still needs one more thing...
Okay, so this is both a "comment" and question. First, is the working example that may help others in search of a asp.net webmethod / jqGrid approach. The code below completely works for sending/receiving JSON parameters from and to jqGrid in order to have correct paging, sorting, filtering (with single search only) utilizing LINQ.. it uses pieces from here and there...
Second, is my question: Has anyone determined an appropriate method for accounting for dynamic operators being sent to the codebehind? Since the client can potentially send "eq" (equal), "cn" (contains) "gt" (greater than), I need a better way of dynamically generating a whereclause that isn't just limited to me building a whereclause string with "=" or "<>", but rather can encompass that along with Dynamic Linq's ability to utilize .Contains or .EndsWith, etc.
I may need some sort of predicate builder function ..
code that handles this as of now (which works, but is limited):
if (isSearch) {
searchOper = getOperator(searchOper); // need to associate correct operator to value sent from jqGrid
string whereClause = String.Format("{0} {1} {2}", searchField, searchOper, "@" + searchField);
//--- associate value to field parameter
Dictionary<string, object> param = new Dictionary<string, object>();
param.Add("@" + searchField, searchString);
query = query.Where(whereClause, new object[1] { param });
}
On with the show.........
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First, THE JAVASCRIPT
<script type="text/javascript">
$(document).ready(function() {
var grid = $("#grid");
$("#grid").jqGrid({
// setup custom parameter names to pass to server
prmNames: {
search: "isSearch",
nd: null,
rows: "numRows",
page: "page",
sort: "sortField",
order: "sortOrder"
},
// add by default to avoid webmethod parameter conflicts
postData: { searchString: '', searchField: '', searchOper: '' },
// setup ajax call to webmethod
datatype: function(postdata) {
$(".loading").show(); // make sure we can see loader text
$.ajax({
url: 'PageName.aspx/getGridData',
type: "POST",
contentType: "application/json; charset=utf-8",
data: JSON.stringify(postdata),
dataType: "json",
success: function(data, st) {
if (st == "success") {
var grid = $("#grid")[0];
grid.addJSONData(JSON.parse(data.d));
}
},
error: function() {
alert("Error with AJAX callback");
}
});
},
// this is what jqGrid is looking for in json callback
jsonReader: {
root: "rows",
page: "page",
total: "totalpages",
records: "totalrecords",
cell: "cell",
id: "id", //index of the column with the PK in it
userdata: "userdata",
repeatitems: true
},
colNames: ['Id', 'First Name', 'Last Name'],
colModel: [
{ name: 'id', index: 'id', width: 55, search: false },
{ name: 'fname', index: 'fname', width: 200, searchoptions: { sopt: ['eq', 'ne', 'cn']} },
{ name: 'lname', index: 'lname', width: 200, searchoptions: { sopt: ['eq', 'ne', 'cn']} }
],
rowNum: 10,
rowList: [10, 20, 30],
pager: jQuery("#pager"),
sortname: "fname",
sortorder: "asc",
viewrecords: true,
caption: "Grid Title Here",
gridComplete: function() {
$(".loading").hide();
}
}).jqGrid('navGrid', '#pager', { edit: false, add: false, del: false },
{}, // default settings for edit
{}, // add
{}, // delete
{ closeOnEscape: true, closeAfterSearch: true}, //search
{}
)
});
</script>
==================================================
Second, THE C# WEBMETHOD
[WebMethod]
public static string getGridData(int? numRows, int? page, string sortField, string sortOrder, bool isSearch, string searchField, string searchString, string searchOper) {
string result = null;
MyDataContext db = null;
try {
//--- retrieve the data
db = new MyDataContext("my connection string path");
var query = from u in db.TBL_USERs
select new User {
id = u.REF_ID,
lname = u.LAST_NAME,
fname = u.FIRST_NAME
};
//--- determine if this is a search filter
if (isSearch) {
searchOper = getOperator(searchOper); // need to associate correct operator to value sent from jqGrid
string whereClause = String.Format("{0} {1} {2}", searchField, searchOper, "@" + searchField);
//--- associate value to field parameter
Dictionary<string, object> param = new Dictionary<string, object>();
param.Add("@" + searchField, searchString);
query = query.Where(whereClause, new object[1] { param });
}
//--- setup calculations
int pageIndex = page ?? 1; //--- current page
int pageSize = numRows ?? 10; //--- number of rows to show per page
int totalRecords = query.Count(); //--- number of total items from query
int totalPages = (int)Math.Ceiling((decimal)totalRecords / (decimal)pageSize); //--- number of pages
//--- filter dataset for paging and sorting
IQueryable<User> orderedRecords = query.OrderBy(sortfield);
IEnumerable<User> sortedRecords = orderedRecords.ToList();
if (sortorder == "desc") sortedRecords= sortedRecords.Reverse();
sortedRecords = sortedRecords
.Skip((pageIndex - 1) * pageSize) //--- page the data
.Take(pageSize);
//--- format json
var jsonData = new {
totalpages = totalPages, //--- number of pages
page = pageIndex, //--- current page
totalrecords = totalRecords, //--- total items
rows = (
from row in sortedRecords
select new {
i = row.id,
cell = new string[] {
row.id.ToString(), row.fname, row.lname
}
}
).ToArray()
};
result = Newtonsoft.Json.JsonConvert.SerializeObject(jsonData);
} catch (Exception ex) {
Debug.WriteLine(ex);
} finally {
if (db != null) db.Dispose();
}
return result;
}
/* === User Object =========================== */
public class User {
public int id { get; set; }
public string lname { get; set; }
public string fname { get; set; }
}
==================================================
Third, NECESSITIES
In order to have dynamic OrderBy clauses in the LINQ, I had to pull in a class to my AppCode folder called 'Dynamic.cs'. You can retrieve the file from downloading here. You will find the file in the "DynamicQuery" folder. That file will give you the ability to utilized dynamic ORDERBY clause since we don't know what column we're filtering by except on the initial load.
To serialize the JSON back from the C-sharp to the JS, I incorporated the James Newton-King JSON.net DLL found here : http://json.codeplex.com/releases/view/37810. After downloading, there is a "Newtonsoft.Json.Compact.dll" which you can add in your Bin folder as a reference
Here's my USING's block using System; using System.Collections; using System.Collections.Generic; using System.Linq; using System.Web.UI.WebControls; using System.Web.Services; using System.Linq.Dynamic;
For the Javascript references, I'm using the following scripts in respective order in case that helps some folks: 1) jquery-1.3.2.min.js ... 2) jquery-ui-1.7.2.custom.min.js ... 3) json.min.js ... 4) i18n/grid.locale-en.js ... 5) jquery.jqGrid.min.js
For the CSS, I'm using jqGrid's necessities as well as the jQuery UI Theme: 1) jquery_theme/jquery-ui-1.7.2.custom.css ... 2) ui.jqgrid.css
The key to getting the parameters from the JS to the WebMethod without having to parse an unserialized string on the backend or having to setup some JS logic to switch methods for different numbers of parameters was this block
postData: { searchString: '', searchField: '', searchOper: '' },
Those parameters will still be set correctly when you actually do a search and then reset to empty when you "reset" or want the grid to not do any filtering
Hope this helps some others!!!! And thanks if you have time to read and reply regarding the dynamic approach to building the whereclause with operators at runtime