Object reference not instantiated after instantiation (consuming WS of SAP Enterprise Service Workspace)

Question

I am trying to consume some of these services in .Net/C#. Some of the Service could be easily consumed but with others I have got a misleading error.

This a part of the code:

input.AcademicProgramOfStudySelectionByName = new AcademicProgramOfStudyByNameQueryMessage_syncAcademicProgramOfStudySelectionByName();
input.AcademicProgramOfStudySelectionByName.AcademicProgramOfStudyName.languageCode = "DE";

I am getting at the second line the error

Object reference not set to an object instance

but I have created the object in the first line!

The same code works in some other service!

Answer 1

you created the object input.AcademicProgramOfStudySelectionByName, but you did not create its member input.AcademicProgramOfStudySelectionByName.AcademicProgramOfStudyName. As it seems, the constructor of class AcademicProgramOfStudyByNameQueryMessage_syncAcademicProgramOfStudySelectionByName does not populate its member AcademicProgramOfStudyName. So when you try to assign a value to a member of AcademicProgramOfStudyName and that instance is NULL, you get an exception.

Example code:

    AcademicProgramOfStudyByNameQueryResponse_InClient client = 
        new AcademicProgramOfStudyByNameQueryResponse_InClient(); 


    client.ClientCredentials.UserName.UserName = "XX";
    client.ClientCredentials.UserName.Password = "YY";

    AcademicProgramOfStudyByNameQueryMessage_sync input =
        new AcademicProgramOfStudyByNameQueryMessage_sync();


    input.AcademicProgramOfStudySelectionByName = new AcademicProgramOfStudyByNameQueryMessage_syncAcademicProgramOfStudySelectionByName();

    // this is the member that currently is still NULL and has to be created:
    input.AcademicProgramOfStudySelectionByName.AcademicProgramOfStudyName = new <insert whatever class is needed here>

    // now this should work without throwing an exception
   input.AcademicProgramOfStudySelectionByName.AcademicProgramOfStudyName.languageCode = "DE";

    AcademicProgramOfStudyByNameResponseMessage_sync output = 
        new AcademicProgramOfStudyByNameResponseMessage_sync(); 

    output = client.AcademicProgramOfStudyByNameQueryResponse_In(input);