10 Sep 2006

Using DataGridViewComboBoxColumn with Custom Objects

Earlier today i was playing with the DataGridView control. I wanted to have a couple of DataGridViewComboBoxColumns in order to limit the available input options for the user. The documentation clearly mentions the following

Here is sample of a custom object

public class Slot {
	private int id;
	private DateTime dateTime;

	public Slot( int id, DateTime dateTime ) {
		this.id = id;
		this.dateTime = dateTime;
	}

	public int Id {
		get { return this.id; }
	}

	public DateTime DateTime {
		get { return this.dateTime; }
	}
}

And here is the workaround for a one to one mapping

public partial class Form1 : Form 
{
	// here we'll store the value the user selected in one of the comboboxcolumns
	private Object selectedValue;

	public Form1() 
	{
		InitializeComponent();
		selectedValues = new Object[this.dataGridView1.Columns.Count];

		// create a couple of slots an add them to the comboboxcolumns
		for ( int i = 0; i < 10; ++i ) 
		{ 
			Slot slot = new Slot( i, DateTime.Now.AddDays( i ) ); 
			this.Column1.Items.Add( slot ); 
			this.Column2.Items.Add( slot ); 
		} 
		this.Column1.DisplayMember = "DateTime"; 
		this.Column2.DisplayMember = "Id"; 
	} 
	
	private void dataGridView1_CellParsing( object sender, DataGridViewCellParsingEventArgs e ) 
	{ 
		// lookup the selected value 
		e.Value = this.selectedValue; 
		e.ParsingApplied = true; 
	} 
	
	private void dataGridView1_EditingControlShowing( object sender, DataGridViewEditingControlShowingEventArgs e ) 
	{ 
		ComboBox cb = e.Control as ComboBox; 
		if ( cb != null ) 
		{ 
			cb.SelectedIndexChanged -= cb_SelectedIndexChanged; 
			cb.SelectedIndexChanged += cb_SelectedIndexChanged; 
		} 
	} 
	
	void cb_SelectedIndexChanged(object sender, EventArgs e) 
	{ 
		ComboBox comboBox = sender as ComboBox; 
		this.selectedValue = comboBox.SelectedItem; 
	} 
}

Tim Van Wassenhove

Using DataGridViewComboBoxColumn with Custom Objects