userNamePasswordValidationMode次のように、WCF アプリにカスタムを実装しました。
<system.serviceModel>
    <bindings>
        <wsHttpBinding>
            <binding>
                <security mode ="Message">
                    <message clientCredentialType="UserName"/>
                </security>
            </binding>
        </wsHttpBinding>
    </bindings>
    <behaviors>
        <serviceBehaviors>
            <behavior>
                <serviceMetadata httpGetEnabled="True"/>
                <serviceCredentials>
                    <userNameAuthentication userNamePasswordValidationMode="Custom" customUserNamePasswordValidatorType="MyProject.Validator.MyValidator, MyProject" />
                </serviceCredentials>
            </behavior>
        </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" aspNetCompatibilityEnabled="true" />
</system.serviceModel>
これはエラーをスローしませんが、クライアントでサービスを参照してユーザー名とパスワードの資格情報を設定すると、間違ったパスワードを入力してもメソッドが呼び出されます。
Testing.myAPIClient.client = new Testing.myAPIClient();
client.ClientCredentials.UserName.UserName = "test";
client.ClientCredentials.UserName.Password = "wrongpassword";
Console.WriteLine(client.StockQuery("123"));
Console.ReadLine();
メソッドStockQueryは引き続き呼び出され、コードは呼び出されMyValidatorません。
public class MyValidator : UserNamePasswordValidator
    {
        public override void Validate(string userName, string password)
        {
            using (var ax = new AXConnector())
            {
                if (!(bool)ax.CallStaticClassMethod("OnlineUsers", "validateLogon", userName, password))
                {
                    throw new UnauthorizedAccessException("Not Authorised");
                }
            }
        }
    }
編集
ここに私のapp.configがあります:
    <system.serviceModel>
    <bindings>
        <basicHttpBinding>
            <binding name="BasicHttpBinding_IMyAPI" closeTimeout="00:01:00"
                openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
                allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
                maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536"
                messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
                useDefaultWebProxy="true">
                <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
                    maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                <security mode="None">
                    <transport clientCredentialType="None" proxyCredentialType="None"
                        realm="" />
                    <message clientCredentialType="UserName" algorithmSuite="Default" />
                </security>
            </binding>
        </basicHttpBinding>
    </bindings>
    <client>
        <endpoint address="http://myServer:89/MyAPI.svc" binding="basicHttpBinding"
            bindingConfiguration="BasicHttpBinding_IMyAPI" contract="Testing.IMyAPI"
            name="BasicHttpBinding_IMyAPI" />
    </client>
</system.serviceModel>
編集 2
サービス インターフェイス:
[ServiceContract]
public interface IMyAPI
{
    string UserName { [OperationContract] get; [OperationContract] set; }
    string Password { [OperationContract] get; [OperationContract] set; }
    [OperationContract]
    bool StockQuery(string partNo);
    [OperationContract]
    decimal PriceQuery(string partNo, string accNo);
}
サービス クラス:
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required),
ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession, ConcurrencyMode = ConcurrencyMode.Single)]
public class MyAPI : IMyAPI
{
    public string UserName { get; set; }
    public string Password { get; set; }
    public MyAPI()
    {
        this.CheckSecurity();
    }
    private void CheckSecurity()
    {
        if (this.UserName != "test" && this.Password != "123")
        {
            throw new UnauthorizedAccessException("Not Authorised");
        }
    }
    // StockQuery and PriceQuery methods...
}