PRB: Overloaded Methods in a .NET Component May Not Be Version-Compatible for Unmanaged Clients (317626)
The information in this article applies to:
- Microsoft .NET Framework 1.1
- Microsoft .NET Framework 1.0
This article was previously published under Q317626 SYMPTOMS If a managed component has an interface that contains
overloaded methods, and you update the component with more overloaded methods,
the methods may no longer be version-compatible for an unmanaged client. This
may break existing COM (that is, unmanaged) clients. CAUSE Components with overloaded methods are exposed to unmanaged
clients as <methodName>_n, where
n varies from two to the total number of overloads
for that specific method. If you add a new overloaded method, the numbering
scheme may generate a different name for the same method. STATUS This behavior is by design. MORE INFORMATION If the managed component has an interface with the
following overloaded members
void TestMethod(short a);
void TestMethod(long a);
void TestMethod(string a);
these methods are exposed to the unmanaged client (that is, the COM
client) respectively as the following:
HRESULT TestMethod(short a);
HRESULT TestMethod_2(__int64 a);
HRESULT TestMethod_3(BSTR a);
If you add another overloaded method to update this component, and if
the method is added between the existing methods in order, as follows
void TestMethod(short a);
void TestMethod(int a);
void TestMethod(long a);
void TestMethod(string a);
the class is exposed to the unmanaged client respectively as the
following:
HRESULT TestMethod(short a);
HRESULT TestMethod_2(long a);
HRESULT TestMethod_3(__int64 a);
HRESULT TestMethod_4(BSTR a);
This change is version-compatible in a managed client. However, for an
unmanaged client, these methods are unintuitive and are not version
compatible. In the example, initially
void TestMethod(long a);
is exposed to the unmanaged client as the following:
HRESULT TestMethod_2(__int64 a);
When you add a new overloaded method to update this component, the same
method in the component is exposed to the unmanaged client as the following:
HRESULT TestMethod_3(__int64 a);
| Modification Type: | Major | Last Reviewed: | 4/8/2003 |
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| Keywords: | kbCOMInterop kbprb KB317626 |
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