Access a static resource in CS Code in ASP.NET Razor pages

In an ASP.NET Core Razor Pages application, if you want to access a static file path (like a file in wwwroot) from a .cs file (C# code) — you typically need the absolute file system path to that static file.

Here’s how to do it properly:

Step-by-Step: Access Static File Path in Code-Behind or Service

1. Inject IWebHostEnvironment

This service provides access to WebRootPath, which points to wwwroot.

Example in Razor Page Code-Behind:

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.RazorPages;
using System.IO;

public class MyPageModel : PageModel
{
    private readonly IWebHostEnvironment _env;

    public MyPageModel(IWebHostEnvironment env)
    {
        _env = env;
    }

    public void OnGet()
    {
        // files is a folder in wwwroot folder.
        string filePath = Path.Combine(_env.WebRootPath, "files", "example.txt"); 
        // Now you can use filePath to read or write the static file
    }
}

If You’re in a Service (not a Razor Page)

Just Inject the IWebHostEnvironment in the constructor:

public class MyService
{
    private readonly IWebHostEnvironment _env;

    public MyService(IWebHostEnvironment env)
    {
        _env = env;
    }

    public string GetStaticFilePath(string filename)
    {
        return Path.Combine(_env.WebRootPath, "downloads", filename);
    }
}

WebRoot vs ContentRoot

• env.WebRootPath → points to wwwroot/
• env.ContentRootPath → points to the base of the project (useful if your file is not in wwwroot), but in the project itself.