Xamarin 表单 ios 在 iOS 中调用 Web 服务时出现异常

Question

I got an exception when calling web API in Xamarin ios(android is working fine), My step is

1. use svcutil.exe to generate the config and C# file

<!--config file-->
<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <system.serviceModel>
        <bindings>
            <basicHttpBinding>
                <binding name="BasicHttpBinding_IOrderApi" />
            </basicHttpBinding>
        </bindings>
        <client>
            <endpoint address="http://40.115.139.190:9002/OrderApi.svc" binding="basicHttpBinding"
                bindingConfiguration="BasicHttpBinding_IOrderApi" contract="IOrderApi"
                name="BasicHttpBinding_IOrderApi" />
        </client>
    </system.serviceModel>
</configuration>

/* C# */
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "4.0.0.0")]
[System.ServiceModel.ServiceContractAttribute(ConfigurationName="IOrderApi")]
public interface IOrderApi
{
...    
[System.ServiceModel.OperationContractAttribute(Action="http://tempuri.org/IOrderApi/GetLoginToken", ReplyAction="http://tempuri.org/IOrderApi/GetLoginTokenResponse")]
    string GetLoginToken(string args);

[System.ServiceModel.OperationContractAttribute(Action="http://tempuri.org/IOrderApi/GetLoginToken", ReplyAction="http://tempuri.org/IOrderApi/GetLoginTokenResponse")]
    System.Threading.Tasks.Task<string> GetLoginTokenAsync(string args);

...
}

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "4.0.0.0")]
public interface IOrderApiChannel : IOrderApi, System.ServiceModel.IClientChannel
{
}

[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "4.0.0.0")]
public partial class OrderApiClient : System.ServiceModel.ClientBase<IOrderApi>, IOrderApi
{

    public OrderApiClient()
    {
    }

    public string GetLoginToken(string args)
    {
        return base.Channel.GetLoginToken(args);
    }

    public System.Threading.Tasks.Task<string> GetLoginTokenAsync(string args)
    {
        return base.Channel.GetLoginTokenAsync(args);
    }
}

2. call web api GetLoginToken in Xamarin form

/* Xamarin Form */
private void DoProcess()
{
    LoginData loginData = new LoginData();

    loginData.StaffCorpCode = CompanyEdit.Text;
    loginData.StaffId = MemberEdit.Text;
    loginData.StaffPassword = PasswordEdit.Text;

    OrderApiClient client = new OrderApiClient(new BasicHttpBinding(), new EndpointAddress("http://40.115.139.190:9002/OrderApi.svc"));

    string loginReturn = client.GetLoginToken(JsonConvert.SerializeObject(loginData));
}

Will get exception in form when calling client. GetLoginToken (only in ios, android no issue). the exception is MonoTouch does not support dynamic proxy code generation. Override this method or its caller to return specific client proxy instance . How to fix this issue?

Answer 1

So, there are some issue with WcfCore and Mono in iOS. For example it can not generate a dynamic proxi. If you will see your code, you will find out that IOrderApiChannel has no implementations. In WCF core this will creates in runtime. But in youe case you should implement it by hands.

ChannelFactory has a virtual method CreateChannel(). If this is not overridden, it uses dynamic code generation, which fails on MonoTouch.

The solution is to override it and provide your own compile-time implementation. Here the good example: File chat generated by svc util https://github.com/sami1971/SimplyMobile/blob/master/Core/Plugins/Stocks/SimplyMobile.Plugins.WcfStockService/StockQuoteServiceClient.cs

File that created by hands: https://github.com/sami1971/SimplyMobile/blob/master/Core/Plugins/Stocks/SimplyMobile.Plugins.WcfStockService/StockQuoteServiceClient.iOS.cs