Hi there... i am still using old version Infragistics ASP.Net 2015.1 via MVC on VS 2015...
sample:

settings.ColumnSetting().ColumnKey("CID").Required(false).ReadOnly(false)
                            .EditorType(ColumnEditorType.Combo)
                            .ComboEditorOptions(co => co.DataSource(companies).ID("CIDCombo").ValueKey("CO").TextKey("CO").Mode(ComboMode.DropDown).EnableClearButton(false)
                            .MultiSelectionSettings(ms => ms.Enabled(true).ShowCheckBoxes(true).ItemSeparator(","))
                            .DropDownOrientation(ComboDropDownOrientation.Bottom)
                        )

so, my db-table field CID (comma delimited string values) would require to bind to this combo editor with multi selection capability...  however, i cannot get the API required per your javascript sample...  please, advise if it's because either the version I have is too old or because I might be missing any references...  if you have a sample for my situation i will appreciate it...

Note: I want to stick to the MVC way if possible...

The solution provided requires using JavaScript as it is extending the jQuery object to add functionality that doesn't exist out of the box in the EditorProviderCombo.  If you wanted to have an MVC wrapper for this you would need to create the new EditorProvider as in the above example and then write your own MVC wrapper for it.

Hi,

Can you give us some code example for this in mvc?

Because whenever i tried to create a editor provider in mvc it is showing the error 'Unable to create editorprovider'  

George,

Please share a sample containing your attempt a creating the editor provider that reproduces the error 'Unable to create editorprovider' so that we can review what is happening.

@using Infragistics.Web.Mvc




    <script type="text/javascript">
        var northwindProductsJSON = [
      { "ID": 0, "Name": "Bread", "Description": "Whole grain bread", "Price": "2.5", "CategoryID": "Food" },
      { "ID": 1, "Name": "Milk", "Description": "Low fat milk", "Price": "3.5", "CategoryID": "Beverages" },
      { "ID": 2, "Name": "Vint Soda", "Description": "Americana Variety ", "Price": "20.9", "CategoryID": "Beverages" },
      { "ID": 3, "Name": "Havina Cola", "Description": "The Original Key Lime Cola", "Price": "19.9", "CategoryID": "Beverages" },
      { "ID": 4, "Name": "Fruit Punch", "Description": "Mango flavor, 8.3 Ounce Cans (Pack of 24)", "Price": "22.99", "CategoryID": "Beverages" },
      { "ID": 5, "Name": "Cranberry Juice", "Description": "16-Ounce Plastic Bottles (Pack of 12)", "Price": "22.8", "CategoryID": "Beverages" },
      { "ID": 6, "Name": "Pink Lemonade", "Description": "36 Ounce Cans (Pack of 3)", "Price": "18.8", "CategoryID": "Beverages" },
      { "ID": 7, "Name": "DVD Player", "Description": "1080P Upconversion DVD Player", "Price": "35.88", "CategoryID": "Electronics" },
      { "ID": 8, "Name": "LCD HDTV", "Description": "42 inch 1080p", "Price": "1088.8", "CategoryID": "Electronics" }
        ],
         northWindCategoriesJSON = [
             { "ID": 0, "Name": "Food" },
             { "ID": 1, "Name": "Beverages" },
             { "ID": 2, "Name": "Electronics" }
         ];
        $(function () {

            $("#grid").igGrid({
                dataSource: northwindProductsJSON,
                autoGenerateColumns: true,
                primaryKey: "ID",
                autoCommit: true,
            features: [
            {
              name: 'Updating',
               
                columnSettings: [{
                    //The combo is defined as a custom editor provider. Combo options are defined under 'editorOptions'.
                    columnKey: "CategoryID",
                   editorProvider: new $.ig.ComboEditorProviderCustom(),
                    editorOptions: {
                        mode: "dropdown",
                        dataSource: northWindCategoriesJSON,
                        textKey: "Name",
                        valueKey: "Name",
                        allowCustomValue: true,
                        multiSelection: {
                            enabled: true,
                            showCheckboxes: true,
                            itemSeparator: ', '
                        }
                    }
                }]
            }]
        });
        });
        $(function () {
        $.ig.ComboEditorProviderCustom = $.ig.EditorProviderCombo.extend({
            getValue: function () {
                var val = this.editor.value();
                var text = this.editor.text();
                if ($.type(val) === "array" && val.length) {
                    //When the passed value is of complex type return the text instead. 
                    //This will be the value saved in the grid data source after editing ends.
                    return text;
                }
                return val;
            },
            setValue: function (val, fire) {
                var array = [];
                this.editor.deselectAll();
                if (this.options.multiSelection.enabled && val.contains(this.options.multiSelection.itemSeparator)) {
                    //if multiSelection is enabled and the value passed from the grid cell to the edito contains the specified itemSeparator
                    //Then split the value by the separator and set a complex value back to the editor so that the matching items will get selected.
                    array = val.split(this.options.multiSelection.itemSeparator);
                    return this.editor.value(array, null, fire);
                }
                this.editor.value(val, null, fire);
            }
        });
        });
    </script>


    
<body>
    <table id="grid"></table>
</body>

Am getting error in this line 

editorProvider: new $.ig.ComboEditorProviderCustom(),

Error is Object doesn't support this action