This setting can be set in both the Model or the Controller, depending on your preferences. In this example, we are using a method setting up the grid for search mode in the Controller.

When a column is searchable, you can select how end-users will edit it. This is controlled by the Column.SearchType property and current has two different options - TextBox and DropDown.

In addition to that, you can specify the values end-users will see in value:name pairs in the EditValues property of Columns - this is especially useful for SearchType.DropDown. Here is an example

Here is some sample code how you can setup dropdowns in additoin to textboxes.

       private void SetUpGrid(JQGrid ordersGrid)
       {
            // show the search toolbar
            ordersGrid.ToolBarSettings.ShowSearchToolBar = true;
            ordersGrid.Columns.Find(c => c.DataField == "OrderID").Searchable = false;
            ordersGrid.Columns.Find(c => c.DataField == "OrderDate").Searchable = false;            

            SetUpCustomerIDSearchDropDown(ordersGrid);
            SetUpFreightSearchDropDown(ordersGrid);
            SetShipNameSearchDropDown(ordersGrid);
        }

        private void SetUpCustomerIDSearchDropDown(JQGrid ordersGrid)
        {
            // setup the grid search criteria for the columns
            JQGridColumn customersColumn = ordersGrid.Columns.Find(c => c.DataField == "CustomerID");
            customersColumn.Searchable = true;

            // DataType must be set in order to use searching
            customersColumn.DataType = typeof(string);
            customersColumn.SearchToolBarOperation = SearchOperation.IsEqualTo;
            customersColumn.SearchType = SearchType.DropDown;

            // Populate the search dropdown only on initial request, in order to optimize performance
            if (ordersGrid.AjaxCallBackMode == AjaxCallBackMode.RequestData)
            {
                var northWindModel = new NorthwindDataContext();
                var searchList = from customers in northWindModel.Customers
                                 select new SelectListItem
                                 {
                                     Text = customers.CustomerID,
                                     Value = customers.CustomerID
                                 };

                customersColumn.SearchList = searchList.ToList<SelectListItem>();
                customersColumn.SearchList.Insert(0, new SelectListItem { Text = "All", Value = "" });
            }            
        }

        private void SetUpFreightSearchDropDown(JQGrid ordersGrid)
        {
            // setup the grid search criteria for the columns
            JQGridColumn freightColumn = ordersGrid.Columns.Find(c => c.DataField == "Freight");
            freightColumn.Searchable = true;

            // DataType must be set in order to use searching
            freightColumn.DataType = typeof(decimal);
            freightColumn.SearchToolBarOperation = SearchOperation.IsGreaterOrEqualTo;
            freightColumn.SearchType = SearchType.DropDown;

            // Populate the search dropdown only on initial request, in order to optimize performance
            if (ordersGrid.AjaxCallBackMode == AjaxCallBackMode.RequestData)
            {
                List<SelectListItem> searchList = new List<SelectListItem>();
                searchList.Add(new SelectListItem { Text = "> 10", Value = "10" });
                searchList.Add(new SelectListItem { Text = "> 30", Value = "30" });
                searchList.Add(new SelectListItem { Text = "> 50", Value = "50" });
                searchList.Add(new SelectListItem { Text = "> 100", Value = "100" });

                freightColumn.SearchList = searchList.ToList<SelectListItem>();
                freightColumn.SearchList.Insert(0, new SelectListItem { Text = "All", Value = "" });
            }
        }

        private void SetShipNameSearchDropDown(JQGrid ordersGrid)
        {
            JQGridColumn freightColumn = ordersGrid.Columns.Find(c => c.DataField == "ShipName");
            freightColumn.Searchable = true;
            freightColumn.DataType = typeof(string);
            freightColumn.SearchToolBarOperation = SearchOperation.Contains;
            freightColumn.SearchType = SearchType.TextBox;            
        }