从Visual Studio 2019中的多目标项目调用Web服务

Question

请有人指导我如何从MultiTargetProject调用ASMX服务。下面是我的.proj文件。

如何从MultiTargetProject调用ASMX服务。我创建了 MultiTargetProjectclass类型项目，然后添加ASMX参考。现在的问题是如何从netstandard * .cs文件使用ASMX服务功能。

我已经按照Microsoft的所有指示进行了操作，但是没有运气。 https://docs.microsoft.com/en-us/dotnet/core/additional-tools/wcf-web-service-reference-guide

<Project Sdk="MSBuild.Sdk.Extras/2.0.41">

    <PropertyGroup>
        <TargetFrameworks>net45;netstandard2.0;MonoAndroid90;Xamarin.iOS10;</TargetFrameworks>
        <ProduceReferenceAssembly>true</ProduceReferenceAssembly>
        <UseFullSemVerForNuGet>false</UseFullSemVerForNuGet>
        <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
    </PropertyGroup>
    
    <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
        <DebugType>portable</DebugType>
        <DebugSymbols>true</DebugSymbols>
    </PropertyGroup>

    <ItemGroup Condition=" $(TargetFramework.StartsWith('net45')) ">
        <Compile Include="**\*.shared.cs" />
        <Compile Include="**\*.shared.*.cs" />
    </ItemGroup>

    <ItemGroup Condition=" $(TargetFramework.StartsWith('netstandard')) ">
        <Compile Include="**\*.netstandard.cs" />
        <Compile Include="**\*.netstandard.*.cs" />
    </ItemGroup>

    <ItemGroup Condition=" $(TargetFramework.StartsWith('MonoAndroid')) ">
        <PackageReference Include="Xamarin.GooglePlayServices.Basement" Version="71.1620.0" />
        <PackageReference Include="Xamarin.Android.Support.v4" Version="28.0.0.3" />
        <PackageReference Include="Xamarin.Firebase.Messaging" Version="71.1740.0" />
        <Compile Include="**\*.android.cs" />
        <Compile Include="**\*.android.*.cs" />
        <Compile Include="**\*.androidapple.*.cs" />
    </ItemGroup>

    <ItemGroup Condition=" $(TargetFramework.StartsWith('Xamarin.iOS')) ">
        <Compile Include="**\*.apple.cs" />
        <Compile Include="**\*.apple.*.cs" />
        <Compile Include="**\*.androidapple.*.cs" />
    </ItemGroup>
            
    <ItemGroup>
        <PackageReference Include="System.ServiceModel.Duplex" Version="4.4.*" />
        <PackageReference Include="System.ServiceModel.Http" Version="4.4.*" />
        <PackageReference Include="System.ServiceModel.NetTcp" Version="4.4.*" />
        <PackageReference Include="System.ServiceModel.Security" Version="4.4.*" />
    </ItemGroup>
            
    <ItemGroup>
        <WCFMetadata Include="Connected Services" />
    </ItemGroup>
</Project>

参考链接： https://docs.microsoft.com/en-us/visualstudio/ide/visual-studio-multi-targeting-overview?view=vs-2019

谢谢。