Gets or sets the key for the image that is displayed for the item.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
The property returns an empty string ("") when the is not set for the ListViewItem. The and ImageIndex properties are mutually exclusive, meaning if one is set, the other is ignored. If you set the property, the ImageIndex property is automatically set to -1. Alternatively, if you set the ImageIndex property, the is automatically set to an empty string ("").
If you are using multiple image lists, for small and large icon view, with a ListView control, you should place small and large versions of the image at the same index location in their respective image lists. When switching between views, the index location of the image in one list is used to locate the image in the other list, regardless of the key value specified.