将WCF服务从.NET Framework迁移至.NET 7遇编译错误求助

问题背景 #

将WCF服务从.NET Framework迁移至.NET 7，已通过微软升级助手完成迁移操作，但出现编译错误。

相关代码 #

[WebInvoke(Method = "POST", UriTemplate = "UploadFotoAndroid")]
public string UploadPhotoAndroid(Stream fileContents)
{
    var sFileName = DateTime.Now.ToString("yyyyMMddhhmmssfff") + "foto.png";

    EscreverNoLog("Recebendo arquivo Android - Foto");

    try
    {
        string absFileName = string.Format("{0}\\FileUpload\\{1}"
                                , AppDomain.CurrentDomain.BaseDirectory
                                , sFileName);
        EscreverNoLog("Nome do Arquivo Android - Foto: " + absFileName);

        using (FileStream fs = new FileStream(absFileName, FileMode.Create))
        {
            fileContents.CopyTo(fs);
            fileContents.Close();
        }
        /*
        try
        {
            GerenciaThreadCopia thCopia = new GerenciaThreadCopia();
            thCopia.ChamarThreadCopiaFoto(absFileName);
        }
        catch (Exception)
        {

        }
        */
        return "$$$" + sFileName + "$$$";
    }
    catch (Exception ex)
    {
        EscreverNoLog("Erro recebimento do Arquivo Android - Foto: " + sFileName);
        EscreverNoLog("Mensagem de Erro recebimento do Arquivo Android - Foto: " + ex.Message);
        return "FALHA: " + ex.Message;
    }
} 

编译错误 #

The Type or namespace name 'WebInvoke' could not be found (are you missing a using directive or an assembly reference?)

The Type or namespace name 'Method' could not be found (are you missing a using directive or an assembly reference?)

解决方法 #

1. 安装兼容NuGet包
   在项目中安装System.ServiceModel.Web包，这是.NET 7中支持WCF Web特性的官方兼容包：

   Install-Package System.ServiceModel.Web
   

   也可通过NuGet包管理器搜索安装。

2. 添加命名空间引用
   在代码文件顶部补充using指令：

   using System.ServiceModel.Web;
   

3. 可选：替换过时API
   代码中AppDomain.CurrentDomain.BaseDirectory在.NET 7已标记为过时，建议替换为AppContext.BaseDirectory：

   string absFileName = string.Format("{0}\\FileUpload\\{1}"
                           , AppContext.BaseDirectory
                           , sFileName);
   

说明 #

.NET Framework中WCF的Web相关特性（如WebInvoke）属于System.ServiceModel.Web命名空间，但.NET 7默认不包含该组件，必须手动引入对应NuGet包才能正常使用。

内容的提问来源于stack exchange，提问作者Kamlesh Jangley