Type Library Attributes
The following keywords specify type library information within the context of a library statement in an IDL file.
| Attribute | Usage |
|---|---|
| aggregatable | Defines the coclass as supporting objects that can directly expose another object's interface pointer. |
| appobject | Identifies the coclass as an application object, which is associated with a full EXE application. |
| bindable | Indicates that the property supports data binding. This allows the client to be notified whenever a property has changed value. |
| coclass | Provides a listing of the supported interfaces for a component object. |
| control | Identifies a coclass or library as a COM control, from which a container site will derive additional type libraries or component object classes. |
| custom | Defines a custom attribute (one not defined in MIDL). |
| default | Indicates that the interface or dispinterface, defined within a coclass, represents the default interface. |
| defaultbind | Indicates the single, bindable property that best represents the object. |
| defaultcollelem | Flags the property as an accessor function for an element of the default collection. Used for Microsoft Visual Basic code optimization. |
| defaultvalue | Allows specification of a default value for a typed optional parameter. |
| defaultvtable | Allows an object to have two different source interfaces. |
| dispinterface | Defines a set of properties and methods on which you can call IDispatch::Invoke. |
| displaybind | Indicates a property that should be displayed to the user as bindable. |
| dllname(str) | Defines the name of the DLL that contains the entry points for a module. |
| dual | Identifies an interface that exposes properties and methods both through IDispatch and directly through the Vtable. |
| entry | Specifies an exported function or constant in a module by identifying the entry point in the DLL. |
| helpcontext | Specifies a context identifier that lets the user view information about this element in the Help file. |
| helpfile | Sets the name of the Help file for a type library. |
| helpstring | Specifies a character string that is used to describe the element to which it applies. |
| helpstringdll | Sets the name of the DLL to use to perform the document string lookup. |
| hidden | Indicates that the item exists but should not be displayed in a user-oriented browser. |
| id | Specifies a DISPID for a member function (either a property or a method, in an interface or dispinterface). |
| immediatebind | Indicates that the database will be notified immediately of all changes to a property of a data-bound object. |
| lcid | When applied to the library statement, along with a localeID argument, identifies the locale for a type library or for a function argument and lets you use international characters inside the library block. Within a library statement, from the point where the lcid attribute is used, MIDL will accept input localized according to the specified locale. |
| library | Instructs the MIDL compiler to generate type library information for the interfaces and classes referenced inside the statement. |
| licensed | Indicates that the coclass to which it applies is licensed, and instances must be created using IClassFactory2. |
| nonbrowsable | Indicates that the property appears in an object browser (which does not show property values), but does not appear in a properties browser (which does show property values). |
| noncreatable | Prevents a client from using the default class factory to create instances of an object interface. |
| nonextensible | Specifies that the IDispatch implementation includes only the properties and methods listed in the interface description and cannot be extended with additional members at runtime. |
| oleautomation | Indicates that an interface is compatible with automation. |
| optional | Specifies an optional parameter for a member function. |
| propget | Specifies a property accessor function. |
| propput | Specifies a property-setting function. |
| propputref | Specifies a property-setting function that uses a reference instead of a value. |
| public | Ensures that an alias declared with typedef becomes part of the type library. |
| readonly | Prohibits assigning a new value to a variable. |
| requestedit | Indicates that the property supports the OnRequestEdit notification. |
| restricted | Specifies that a library, or member of a module, interface, or dispinterface cannot be called arbitrarily. |
| retval | Designates the parameter that receives the return value of the member. |
| source | Indicates that a member of a coclass, property, or method is a source of events. |
| string | Indicates that the one-dimensional char, wchar_t, byte (or equivalent) array or the pointer to such an array must be treated as a string. |
| uidefault | Indicates that the type information member is the default member for display in the user interface. |
| usesgetlasterror | Specifies that a module entry point uses SetLastError to return error codes and that a caller can then call GetLastError to retrieve the error code if there is an error on entering a function. |
| uuid | Designates a unique identifier for a type library, coclass, or interface. |
| vararg | Specifies that the function takes a variable number of arguments. |
| version | Identifies a particular version of a type library. |
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