在MAUI中请求https接口帮助类

在MAUI (Microsoft UI XAML) 中，虽然直接使用Blazor的HttpRequestMessage在纯XAML应用中可能不太适用，但你可以通过相似的方式来实现HTTP请求。由于MAUI基于.NET Core和跨平台，我们可以借鉴Blazor的做法来构造网络请求。

首先，创建一个用于发起HTTPS请求的服务类，类似于你在Blazor中定义的`IHolidaysApiService`：

// In a separate service file like HolidayApiService.cs
using System.Net.Http;
using System.Threading.Tasks;

public class HolidayApiService : IHolidaysApiService
{
    private readonly HttpClient _httpClient;

    public HolidayApiService()
    {
        _httpClient = new HttpClient();
        _httpClient.DefaultRequestHeaders.Accept.Clear();
        _httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/vnd.github.v3+json"));
    }

    public async Task<List<HolidayResponseModel>> GetHolidays(HolidayRequestModel holidaysRequest)
    {
        // 使用HttpClient发送GET请求
        HttpResponseMessage response = await _httpClient.GetAsync(url);
        if (!response.IsSuccessStatusCode)
            throw new Exception($"Failed to fetch holidays with status code: {response.StatusCode}");

        string responseBody = await response.Content.ReadAsStringAsync();
        return await Newtonsoft.Json.JsonConvert.DeserializeObjectAsync<List<HolidayResponseModel>>(responseBody);
    }
}

在这里，`_httpClient.GetAsync`用于发起GET请求，响应状态码检查确保请求成功，然后读取返回的JSON内容并解析成`List<HolidayResponseModel>`。

要在MAUI页面上使用这个服务，注入`HolidayApiService`并调用`GetHolidays`方法：

<!-- In your MAUI view or page -->
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2022/xamarinforms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml">
    <StackLayout>
        <!-- Your UI elements... -->
        <Button Content="Fetch Holidays" Clicked="{Binding OnFetchHolidaysClick}" />
    </StackLayout>
</ContentPage>

// And in the corresponding C# code-behind
private HolidayApiService _holidayApiService;
public HolidayApiService HolidayApiService
{
    get => _holidayApiService ??= new HolidayApiService();
    set => _holidayApiService = value;
}

private async void OnFetchHolidaysClick(object sender, EventArgs e)
{
    try
    {
        List<HolidayResponseModel> holidays = await HolidayApiService.GetHolidays(yourRequestObject);
        // Process fetched holidays...
    }
    catch (Exception ex)
    {
        // Handle error...
    }
}