How can I globally set a custom HtmlEncoder to use in all Razor pages?

May 23, 2022

I want to set a custom HtmlEncoder as the default HtmlEncoder to be used in Asp.net Core Razor pages.

The RazorPageBase class does have a HtmlEncoder property which I can set on a single Razor page like this:

using System.Text.Encodings.Web;
using System.Text.Unicode;
@{
    HtmlEncoder = HtmlEncoder.Create(UnicodeRanges.All);
}

Then the HtmlEncoder is used on that page.

Now the obvious thing to try is to apply this code to ‘ViewStart.cshtml’:

using System.Text.Encodings.Web;
using System.Text.Unicode;
@{
    Layout = "_Layout";
    HtmlEncoder = HtmlEncoder.Create(UnicodeRanges.All);
}

However, this does not work, it still uses the default HtmlEncoder (it compiles fine and it does pick up the Layout property).

This means, that to set the default HtmlEncoder for all pages, I have to include the code above to each and every Razor page, including each and every Partial page and of course "_Layout.cshtml".

I hope I have missed something.

How can I specify this on a global scale so it applies to all Razor pages?

>Solution :

In your app configuration, do the following:

[.NET 6 Program.cs]
builder.Services.Configure<WebEncoderOptions>(options =>
{
    options.TextEncoderSettings = new TextEncoderSettings(UnicodeRanges.All);
});

[Pre-.NET 6 Startup.cs]
services.Configure<WebEncoderOptions>(options =>
{
    options.TextEncoderSettings = new TextEncoderSettings(UnicodeRanges.All);
});