Documented current tenant service for blazor UI

docs/en/UI/Blazor/CurrentTenant.md

@@ -1,3 +1,23 @@
 # Blazor UI: Current Tenant
 
-TODO
+`ICurrentTenant` service can be used to get information about the current tenant in a [multi-tenant](../../Multi-Tenancy.md) application. `ICurrentTenant` defines the following properties;
+
+* `Id` (`Guid`): Id of the current tenant. Can be `null` if the current user is a host user or the tenant could not be determined.
+* `Name` (`string`): Name of the current tenant. Can be `null` if the current user is a host user or the tenant could not be determined.
+* `IsAvailable` (`bool`): Returns `true` if the `Id` is not `null`.
+
+**Example: Show the current tenant name on a page**
+
+````csharp
+@page "/"
+@using Volo.Abp.MultiTenancy
+@inject ICurrentTenant CurrentTenant
+@if (CurrentTenant.IsAvailable)
+{
+    <p>Current tenant name: @CurrentTenant.Name</p>
+}
+````
+
+## See Also
+
+* [Multi-Tenancy](../../Multi-Tenancy.md)