...

SubProject/FCOMMON/FCOMMON.csproj

@@ -155,6 +155,7 @@
     <Compile Include="fSFI.Designer.cs">
       <DependentUpon>fSFI.cs</DependentUpon>
     </Compile>
+    <Compile Include="IMyContract.cs" />
     <Compile Include="ISO8601.cs" />
     <Compile Include="keyValuedataTable.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

SubProject/FCOMMON/IMyContract.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.ServiceModel;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace FCOMMON
+{
+    [ServiceContract]
+    public interface IMyContract
+    {
+        [OperationContract]
+        string Hello(string name);
+    }
+
+    // 실제로 Client에서 호출될 함수
+    public class MyService : IMyContract
+    {
+        public string Hello(string name)
+        {
+            return "Hello " + name + "!";
+        }
+    }
+
+}