md41 / localstorage

A library to provide access to local storage in Blazor applications

Blazored LocalStorage

A library to provide access to local storage in Blazor applications

Installing

You can install from NuGet using the following command:

Install-Package Blazored.LocalStorage

Or via the Visual Studio package manager.

Setup

You will need to register the local storage services with the service collection in your Startup.cs file in Blazor Server.

public void ConfigureServices(IServiceCollection services)
{
    services.AddBlazoredLocalStorage();
}

Or in your Program.cs file in Blazor WebAssembly.

public static async Task Main(string[] args)
{
    var builder = WebAssemblyHostBuilder.CreateDefault(args);
    builder.RootComponents.Add<App>("app");

    builder.Services.AddBlazoredLocalStorage();

    await builder.Build().RunAsync();
}

Configuration

The local storage provides options that can be modified by you at registration in your Startup.cs file in Blazor Server.

public void ConfigureServices(IServiceCollection services)
{
    services.AddBlazoredLocalStorage(config =>
        config.JsonSerializerOptions.WriteIndented = true);
}

Or in your Program.cs file in Blazor WebAssembly.

public static async Task Main(string[] args)
{
    var builder = WebAssemblyHostBuilder.CreateDefault(args);
    builder.RootComponents.Add<App>("app");

    builder.Services.AddBlazoredLocalStorage(config =>
        config.JsonSerializerOptions.WriteIndented = true);

    await builder.Build().RunAsync();
}

Usage (Blazor WebAssembly)

To use Blazored.LocalStorage in Blazor WebAssembly, inject the ILocalStorageService per the example below.

@inject Blazored.LocalStorage.ILocalStorageService localStorage

@code {

    protected override async Task OnInitializedAsync()
    {
        await localStorage.SetItemAsync("name", "John Smith");
        var name = await localStorage.GetItemAsync<string>("name");
    }

}

With Blazor WebAssembly you also have the option of a synchronous API, if your use case requires it. You can swap the ILocalStorageService for ISyncLocalStorageService which allows you to avoid use of async/await. For either interface, the method names are the same.

@inject Blazored.LocalStorage.ISyncLocalStorageService localStorage

@code {

    protected override void OnInitialized()
    {
        localStorage.SetItem("name", "John Smith");
        var name = localStorage.GetItem<string>("name");
    }

}

Usage (Blazor Server)

NOTE: Due to pre-rendering in Blazor Server you can't perform any JS interop until the OnAfterRender lifecycle method.

@inject Blazored.LocalStorage.ILocalStorageService localStorage

@code {

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        await localStorage.SetItemAsync("name", "John Smith");
        var name = await localStorage.GetItemAsync<string>("name");
    }

}

The APIs available are:

• asynchronous via ILocalStorageService:

  • SetItemAsync()
  • GetItemAsync()
  • GetItemAsStringAsync()
  • RemoveItemAsync()
  • ClearAsync()
  • LengthAsync()
  • KeyAsync()
  • ContainsKeyAsync()

• synchronous via ISyncLocalStorageService (Synchronous methods are only available in Blazor WebAssembly):

  • SetItem()
  • GetItem()
  • GetItemAsString()
  • RemoveItem()
  • Clear()
  • Length()
  • Key()
  • ContainsKey()

Note: Blazored.LocalStorage methods will handle the serialisation and de-serialisation of the data for you, the exception is the GetItemAsString[Async] method.

If you want to handle serialising and de-serialising yourself, serialise the data to a string and save using the SetItem[Async] method, as normal -- This method will not attempt to serialise a string value. You can then read out the data using the GetItemAsString[Async] method and de-serialise it yourself.