我正在尝试在 .Net/C# 中使用其中的一些服务。某些服务可以很容易地使用，但与其他服务相比，我遇到了误导性错误。
这是代码的一部分：
input.AcademicProgramOfStudySelectionByName = new AcademicProgramOfStudyByNameQueryMessage_syncAcademicProgramOfStudySelectionByName();
input.AcademicProgramOfStudySelectionByName.AcademicProgramOfStudyName.languageCode = "DE";
我在第二行收到错误“对象引用未设置为对象实例”。但我已经在第一行创建了对象！
相同的代码适用于其他一些服务！
您创建了对象
input.AcademicProgramOfStudySelectionByName，但没有创建它的成员input.AcademicProgramOfStudySelectionByName.AcademicProgramOfStudyName。看起来， class 的构造函数AcademicProgramOfStudyByNameQueryMessage_syncAcademicProgramOfStudySelectionByName并没有填充它的 member AcademicProgramOfStudyName。因此，当您尝试将值分配给 的成员AcademicProgramOfStudyName并且该实例为NULL时，您会遇到异常。
示例代码：
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);
这真的很奇怪。看到这个比较：在这段代码中我得到了错误
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();
input.AcademicProgramOfStudySelectionByName.AcademicProgramOfStudyName.languageCode = "DE";
AcademicProgramOfStudyByNameResponseMessage_sync output =
new AcademicProgramOfStudyByNameResponseMessage_sync();
output = client.AcademicProgramOfStudyByNameQueryResponse_In(input);
在这段代码中我没有！
CustomerSimpleByNameAndAddressQueryResponse_InClient client =
new CustomerSimpleByNameAndAddressQueryResponse_InClient();
client.ClientCredentials.UserName.UserName = "XX";
client.ClientCredentials.UserName.Password = "YY";
CustomerSimpleByNameAndAddressQueryMessage_sync input = new CustomerSimpleByNameAndAddressQueryMessage_sync();
input.CustomerSimpleSelectionByNameAndAddress = new CustomerSimpleByNameAndAddressQueryMessage_syncCustomerSimpleSelectionByNameAndAddress();
input.CustomerSimpleSelectionByNameAndAddress.CustomerAddressCityName = "Berlin";
CustomerSimpleByNameAndAddressResponseMessage_sync output = new CustomerSimpleByNameAndAddressResponseMessage_sync();
output = client.CustomerSimpleByNameAndAddressQueryResponse_In(input);