Web Service Method with Optional Parameters [duplicate]

Answer 1

You can achieve optional parameters by overloads and using the MessageName property.

[WebMethod(MessageName = "MyMethodDefault")]
public void MyMethod(int a, int b)
{
      MyMethod( a, b, -3);
}

[WebMethod(MessageName = "MyMethod")]
public void MyMethod(int a, int b, int c)

For this to work, you may also need to change

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] 

to

[WebServiceBinding(ConformsTo = WsiProfiles.None)] 

if you haven't done so already, as WS-I Basic Profile v1.1 does not allow overloads

Answer 2

I've looked into optional parameters etc. before, and straight asmx web services don't support this (with default generated WSDLs). With WCF however, you can mark parameters in your datacontract as IsRequired=false - see Optional parameters in ASP.NET web service

Answer 3

Use methods overloading:

[WebMethod(MessageName = "MyMethod1")]
public void MyMethod(int a, int b)
{
    return MyMethod(a, b, -3);
}

[WebMethod(MessageName = "MyMethod2")]
public void MyMethod(int a, int b, int c)
{
}