Groupable ListView

• Download source files - 32.9 Kb (VS2005 project)
• Download demo project - 10.7 Kb

Introduction

Some time ago, I thought about writing a small extension to the ListView control. This would dynamically create a graphic user interface to allow the end-user create/modify groups, something like ‘GROUP BY’ in SQL. The control will automatically create a ToolStrip and a ToolStripButton for each column.

Usage

To use the control, just add ExListView.cs to your project, and switch the GroupsGUIs property to true, if you want to give the possibility to group items for the users.

Properties

• GroupsGUIs - Show or not the ToolStrip to allow group items.
• ToolStripImage - The image to show on ToolStripButtons of the groups.
• ShowGroupLabel - Show or hide the 'ShowGroup' label.
• ShowGroupLabelText - The 'ShowGroup' label. Default: 'Group by:'.

Example

I prepared a small example project, with a ListView which contains some employees. Each employee has a name, sex, and a job. So, if the user wants to group the employees by sex, he just needs to press one button, and the ListView will analyze each ListViewItem and create groups for the data. It creates one group for each different data in selected colums.

Here you see an example of ListView, grouped by Sex and Job:

Code

To analyze and create the groups, I wrote a GroupBy(ColumnHeader[] Headers) method, it’s a simple thread-safe method with a few loops which add groups for each new different data found.

delegate void dGroupBy(ColumnHeader[] Headers);
public void GroupBy(ColumnHeader[] Headers)
{
    if (this.InvokeRequired)
    {
        dGroupBy d = new dGroupBy(GroupBy);
        this.Invoke(d, new object[] { Headers });
    }
    else
    {
        //code

        foreach (ListViewItem lvi in this.Items)
        {
            string header = "";

            foreach (ColumnHeader ch in Headers)
            {
                header += " " + 
                   lvi.SubItems[ch.Index].Text;
            }
            ListViewGroup group = 
                new ListViewGroup(header);
            ListViewGroup found = null;
            foreach (ListViewGroup g in Groups)
            {
                if (g.Header == group.Header)
                { found = g; break; }
            }
            if (found == null)
            {
                this.Groups.Add(group);
                group.Items.Add(lvi);
            }
            else
            {
                found.Items.Add(lvi);
            }
        }
    }
}

History

• 06/09/06 – v.1.01: Dock fill bug fixed.
• 20/08/06 – Initial release.