Razor directives are special instructions prefixed with @ that control how a component compiles, behaves, and interacts with the framework.

Essential Directives

• @page "/route" — defines a navigable route for the component
• @code { } — C# code block for fields, properties, and methods
• @inject TypeName Identifier — injects a DI service
• @using Namespace — adds a using statement
• @inherits BaseClass — sets a base class for the component
• @implements IInterface — declares an interface implementation
• @attribute [Attribute] — applies a C# attribute to the component class
• @typeparam T — makes the component generic
• @layout LayoutName — overrides the default layout
• @namespace MyApp.Pages — sets the component namespace
• @rendermode — sets the render mode (Blazor 8+)

_Imports.razor

Add common @using and @inject statements to _Imports.razor — they apply to all components in the same folder and subfolders. This eliminates repetitive using statements at the top of every file.

Reference:

Wikipedia: Razor

https://en.wikipedia.org/wiki/Blazor