Paul Kimmel's Blog

I manage a TODO list with Microsoft Outlook. If it weren’t for Outlook and Calendar items synched on my iPhone I would forgot a lot of detailed tasks. Right now there are so many new features for 10.2 that I want to cover that my task list has gotten pretty long and is growing and projecting out for several weeks to come. It is long enough right now that I wonder if I am going to get some sleep this weekend or get to that 30 foot trunk of a tree that the wind just knocked over into my yard. The last week or so sleep has been at the bottom of the TODO list—although I did wheeze through 30 minutes of basketball at the gym last night.

The feature on the menu today is a single feature, the CustomFilterPopupItems event for the XtraPivotGrid. The XtraPivotGrid is a composable, searchable, sortable, filterable grid that supports data mining type tasks for your end users. The CustomFilterPopupItems event is new in 10.2 and is fired when the user displays the filter list for a field. Figure 1 shows the demo application with the filter list visible. A user brings up the filter list by clicking on the little filter button associated with a given field.

Figure 1: Pivot Grid Control with the filter items visible for the Category Name field. 

This demo handles the CustomFilterPopupItems event for the XtraPivotGrid control. Normally when you display the filter and deselect items those elements are removed from the result set—the data area in the grid and the row area. For example, if you expand the Category Name filter and uncheck Show All and check Beverages then the default behavior is that the products that are beverages are the only products shown .

By default the non-visible data items are available in the filter still. This sample demonstrates how to hide the checked filter items that aren’t visible in the grid. For example, in our scenario by checking the Beverages Category only beverages are visible in the grid, and with the sample code for CustomFilterPopupItems in Listing 1 the invisible items are also removed from the filter list. For instance, if you drop the Category Name filter in our scenario then the event code removes items that for all intents and purposes won’t be displayed anyway.

Figure 2 shows the Beverages scenario without the event code, and Figure 3 shows the scenario with the event code.

  
Figure 2: Notice that even though Beverages is the only Category checked all products are visible in the Product Name filter.

Figure 3: With the CustomFilterPopupItems event (as written in Listing 1) invisible items are removed from the popup filter list.

Listing 1: Using the CustomFilterPopupItems event to hide filter items that aren’t being displayed in the data grid based on other filter selections.

using System;

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using DevExpress.XtraPivotGrid.Data;

namespace EmptyWinApp {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e) {
            // TODO: This line of code loads data into the 'productReports._ProductReports' 
            // table. You can move, or remove it, as needed.
            this.productReportsTableAdapter.Fill(this.productReports._ProductReports);
        }

        private void pivotGridControl1_CustomFilterPopupItems(object sender, 
        DevExpress.XtraPivotGrid.PivotCustomFilterPopupItemsEventArgs e) 
        {
            List<object> values = e.Field.GetVisibleValues();
            values.Sort();
            for(int i = e.Items.Count - 1; i >= 0; i--) {
                if(e.Items[i].IsChecked == true && values.BinarySearch(e.Items[i].Value) < 0)
                    e.Items.RemoveAt(i);
            }
        }
    }
}