Explicity qualifying the methods with Interface names would help
public interface ISum1
{
int Sum(int a, int b);
}
public interface ISum2
{
int Sum(int a, int b);
}
public class MainClass : ISum1, ISum2
{
int ISum1.Sum(int a, int b)
{
return a + b;
}
int ISum2.Sum(int a, int b)
{
return a * b;
}
}
public class Test
{
public void TestMethod()
{
int result;
ISum1 is1 = new MainClass();
result = is1.Sum(2,3);
ISum2 is2 = new MainClass();
result = is2.Sum(2,3);
}
}