How to change the default layout in blazor once it set in App.razor?

Question

In my application I am planning to set two layouts. BeforeLoginLayout and AfterLoginLayout. As of now , in App.Razor, I set the defaultLayout as BeforeLoginLayout. I would like to change the default layout after user logged into application. How to do this in Blazor ? I can set it in individual page. I would like to avoid this and set as the default layout.

Answer 1

Here's some code and a demo page which shows how to change out the layout dynamically. You should be able to adapt this to fit your requirement.

Modify App as follows:

<Router AppAssembly="@typeof(Program).Assembly" PreferExactMatches="@true">
    <Found Context="routeData">
        <CascadingValue Value="this">
            <RouteView RouteData="@routeData" DefaultLayout="this.LayoutType" />
        </CascadingValue>
    </Found>
    <NotFound>
        <LayoutView Layout="@typeof(MainLayout)">
            <p>Sorry, there's nothing at this address.</p>
        </LayoutView>
    </NotFound>
</Router>

@code {

    private Type LayoutType = typeof(MainLayout);

    public void SetLayout(Type layout)
    {
        if (layout != LayoutType)
        {
            this.LayoutType = layout;
            StateHasChanged();
        }
    }
}

This demo page then shows how to change out the layouts dynamically. OtherLayout is a copy of MainLayout with something to differentiate it.

@page "/"

<div class="m-2 p-2">
    <button class="btn btn-secondary" @onclick="() => ButtonClick(typeof(MainLayout))">Main Layout</button>
    <button class="btn btn-dark ms-2" @onclick="() => ButtonClick(typeof(OtherLayout))">Other Layout</button>
</div>


@code {

    [CascadingParameter] public App MyApp { get; set; }


    void ButtonClick(Type layoutType)
    {
        MyApp.SetLayout(layoutType);
    }
}