[fdo-dev] Enumerating connection properties

Mateusz Loskot mateusz at loskot.net
Tue Oct 24 10:52:47 EDT 2006

Mateusz Loskot wrote:
> Greg Boone wrote:
>> This allows a caller to specify
>> a subset of the connection properties in order to find out the valid
>> values for the remaining properties. This behavior is defined by the
>> provider itself and allows a user to specify a subset of the connection
>> properties, connect and then request that the provider enumerate the
>> remaining connection property values. 
> Why there is no interface to ask provider which properties are
> connection-less and which require pending connection?
> Or does it mean every enumerable property does always need pending
> connection?
> So, if IsPropertyEnumerable() returns TRUE, then one should not call
> FdoIConnectionPropertyDictionary::EnumeratePropertyValues()
> if connection is not Open()

May be it will be more clear if I present some code snippet that
explains what I'm asking about.
Following code only lists connection properties for OSGeo.MySQL.3.2.
I want to list *only* these properties accessible *without* any
connection, open or pending.
The question is (marked inline): How to detect these properties ?

FdoPtr<IConnectionManager> mgr;
mgr = FdoFeatureAccessManager::GetConnectionManager();

FdoPtr<FdoIConnection> conn;
conn = mgr->CreateConnection(L"OSGeo.MySQL.3.2");

FdoPtr<FdoIConnectionInfo> ci;
ci = conn->GetConnectionInfo();

FdoPtr<FdoIConnectionPropertyDictionary> dict;
dict = ci->GetConnectionProperties();

FdoInt32 dictSize = 0;
FdoString** names = dict->GetPropertyNames(dictSize);

for (FdoInt32 i = 0; i < dictSize; i++)
    FdoString* property = names[i];

    // Display property name
    std::wcout << property << std::endl;

    // Display property details, if it's protected, required
    // ...

    // How do I know which property I can enumerated without
    // connection and which I can not?

    // Enumerate what's enumerable
    if (dict->IsPropertyEnumerable(property))
        FdoInt32 valuesSize = 0;
        FdoString** values = dict->EnumeratePropertyValues(property,

        for (FdoInt32 j = 0; j < valuesSize; j++)
            std::wcout << values[j] << std::endl;

May be the condition logic above

if (dict->IsPropertyEnumerable(property))

should look as follows:

FdoConnectionState state = conn->GetConnectionState();
if (FdoConnectionState_Open==state || FdoConnectionState_Pending==state)
   // Now, I can safely list what's enumerable?
   if (dict->IsPropertyEnumerable(property)) {}

I'd like to underline that
1) I'm aware some properties can be listed only if connection is
open or pending.
2) I'd like to list properites which *can* be listed without
connecting to any data source.

Is this feasible?

Mateusz Loskot

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