Multi Column ComboBox

• Download source files - 14 Kb
• Download demo project - 38.6 Kb

Introduction

This is a simple example of how to display table values (i.e. multiple columns) in a combo box. For the dropdown window, a form with a ListView docked to fill can be used. The MultiColumnCombobox class is inherited from the System.Windows.Forms.Combobox class.

protected override void OnDropDown(System.EventArgs e){
    Form parent = this.FindForm();
    if(this.dataTable != null || this.dataRows!= null){
        MultiColumnComboPopup popup = new 
                            MultiColumnComboPopup(this.dataTable,
                            ref this.selectedRow,columnsToDisplay);
        popup.AfterRowSelectEvent+=
                            new AfterRowSelectEventHandler
                            (MultiColumnComboBox_AfterSelectEvent);
        popup.Location = new Point(parent.Left + 
                            this.Left + 4 ,parent.Top + 
                            this.Bottom + this.Height);
        popup.Show();
        ..........................

The OnDropDown event of the ComboBox is overridden to display our popup from. The popup form should never be a modal, because the popup has to close, if the user decides to click elsewhere other than the grid on the dropdown form. To check where the user has selected something, I use the popup.AfterRowSelectEvent, to fire an event on the MulticolumnComboBox. To use the MulticolumnComboBox do the following:

multiColumnComboBox1.Table = dtable;//DataTable
//Column to display after selection
multiColumnComboBox1.DisplayMember = "Band";
multiColumnComboBox1.ColumnsToDisplay = new 
    string[]{"Band","Song","Album"};//columns to display
//in the dropdown grid

After the DataTable is assigned to the combo, the dropdown looks like this:

After Selection, the DisplayMember of that row is displayed.

The SourceCode is pretty much self-explanatory, download it and try it out.

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here