Selecting

When the user clicks on a thumbnail item in the display, any of several things will happen (depending on the way that ImGearThumbnailCtl Class properties are set, and how the mouse button is used):

Left-click to select an item under the cursor. If the MultiSelect Property value is set to false, then all other items are deselected. Double-clicking fires an event with the Index parameter set to the item being clicked. If this parameter is equal to -1 then the cursor is outside any thumbnail image. Typically, this event causes the application to load the corresponding image into the main program window.

Right-click to show the thumbnail magnifier if the ShowMagnify Property has been set to true. Releasing the right mouse button will hide the magnifier.

ImGearThumbnailCtl Class will automatically change the appearance of the selected thumbnail item, as per the SelectionBackColor Property and SelectionForeColor Property.

The application can also apply a different appearance to selected thumbnail items, called "Highlighting" them. Each thumbnail item has a Highlighted Property that can be set by the application. When the Highlighted Property is set, the thumbnail item's appearance is determined by the HighlightBackColor Property and HighlightForeColor Property.

ImGearThumbnailCtl Class supports MultiSelect. If the MultiSelect Property is set to true, then the user can select multiple thumbnail items at a time (using Ctrl-click and Shift-click).