Blazor Dropdown List Component - Overview
Feature-rich, the Blazor Dropdown list offers out-of-the-box filtering, accessibility, preselected values, flexible data binding, grouping, UI customization, and more. What this component practically does is to effectively and easily replace HTML select tags, enabling users to quickly choose a non-editable value from a predefined set of several options.
The Ignite UI for Blazor Dropdown component displays an toggle list of predefined values and allows users to easily select a single option item with a click. It can be quickly configured to act as a Blazor dropdown menu or you can simply use it to deliver more useful visual information by grouping data. Also, with grouping you can use both flat and hierarchical data.
With our component, you get all the functions and customization options you need for your project – styling customizations, Blazor Dropdown placement options, templates and ability to change what and how is displayed in the header, footer, body, list, etc.
Blazor Dropdown Example
The following Blazor Dropdown List example demonstrates the use of simple interactive Blazor Dropdown menu in action with three basic options to choose from. See how it works.
How to use the Dropdown List with Ignite UI for Blazor
Before using the IgbDropdown, you need to register it as follows:
// in Program.cs file
builder.Services.AddIgniteUIBlazor(typeof(IgbDropdownModule));
Target
The Blazor Dropdown list is positioned relatively to its target. The target slot allows you to provide a built-in component which toggles the open property on click. In some cases you would want to use an external target or use another event to toggle the opening of the Dropdown. You can achieve this using the Show2, Hide and Toggle2 methods which allow you to provide the target as a parameter. By default, the Dropdown list uses absolute CSS position. You will need to set the PositionStrategy of the Blazor Dropdown to fixed when the target element is inside a fixed container, but the Dropdown is not. The Dropdown list is automatically sized based on its content, if you want the list to have the same width as the target, you should set the SameWidth property to true.
Position
The preferred placement of the Blazor Dropdown can be set using the Placement property. The default placement of the Dropdown is bottom-start. The Flip property determines whether the placement should be flipped if there is not enough space to display the Dropdown at the specified placement. The distance from the Blazor Dropdown list to its target can be specified using the Distance property.
Selection
The IgbDropdown emits the Change event when the user selects an item. The Select method of the Dropdown allows you to select an item by its index or value.
Item
The IgbDropdownItem represents a selectable item in the Dropdown list. You could predefine a selected item by setting the Selected property. You could also disable an item so that it can't be selected using the Disabled property. The IgbDropdownItem has a default slot which allows you to specify the content of the item. You could also provide custom content to be rendered before or after the content using the prefix and suffix slots. The Value property allows you to provide a custom value to an item. If the Value is not set, it resolves to the text content of the item.
Header
You could use the IgbDropdownHeader to provide a header for a group of items.
Group
The Blazor Dropdown's items can also be grouped using the IgbDropdownGroup, making it easier for users to differentiate separate categories. See it in action in this Blazor Dropdown List example:
Scroll Strategy
The ScrollStrategy property determines the behavior of the component during scrolling the container of the target element. The default value is scroll which means that the Dropdown will be scrolled with its target. Setting the property to block will block the scrolling if the Dropdown is opened. You could also set the property to close which means that the Dropdown will be closed automatically on scroll.
Keep Open
By default, the Dropdown is closed automatically when the user clicks outside of it or selects an item. You could prevent this behavior using the KeepOpenOnOutsideClick and KeepOpenOnSelect properties.
Styling
You can change the appearance of the Dropdown and its items, by using the exposed CSS parts. The IgbDropdown exposes base and list parts, the IgbDropdownItem exposes prefix, content and suffix parts and the IgbDropdownGroup exposes label part.