private void btnBackColor_Click(object sender, System.EventArgs e)
{
//Create new ColorDialog control
ColorDialog colorDialog = new ColorDialog();
//Show the ColorDialog and exit if user cancelled
if (colorDialog.ShowDialog() == DialogResult.Cancel) return;
//Get color from ColorDialog
System.Drawing.Color color = colorDialog.Color;
//The ToolbarControl host wrapper expects a SystemDrawingColor. The
//ToolbarControl type library wrapper expects an OLE_Color. The OLE_Color
//is made up as follows:(Red) + (Green * 256) + (Blue * 256 * 256)
//IToolbarControl2 toolbarControl = (IToolbarControl2) axToolbarControl1.Object;
//toolbarControl.BackColor = (color.R + (color.G * 256) + (color.B * 256 * 256));
axToolbarControl1.BackColor = color;
colorDialog = null;
}