HyperCube/Pages/GetFile.razor

@page "/getfile"
@using System.IO;
@using System;

@code {
    string text;
    protected override async Task OnInitializedAsync()
    {
        string filepath = @"c:\Users\Администратор\AppData\Local\Ethereum\rinkeby\keystore\UTC--2021-04-21T07-20-25.392048000Z--1841462ee3e39af00de42b067853c58ab7e18876";
        text = File.ReadAllText(filepath);

        //var content = new byte[] { 1, 2, 3 };
        //return new File(content, "application/octet-stream", "name");
        //new File()
    }
}