Web Service Method with Optional Parameters [duplicate]

问题

Possible Duplicate:
Can I have an optional parameter for an ASP.NET SOAP web service

I have tried looking around for this but I really cannot find the right solution for what I want to do. Sorry for the repetition since I know this has been asked before. I have a Web Service Method in which I want to have an optional parameter such as:

public void MyMethod(int a, int b, int c = -3)

I already know I cannot use nullable parameters, so I am just trying to use a default value. Problem is when I call this method without supplying argument c is still get an exception. Is there somewhere I have to specify it is in fact optional?

Thanksю

回答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

回答2:

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)
{
}

回答3:

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

来源：https://stackoverflow.com/questions/7565842/web-service-method-with-optional-parameters