ExternalDefinition Class

The ExternalDefinition object adds properties specific to Autodesk Revit shared parameter definitions.

Inheritance Hierarchy

SystemObject
Autodesk.Revit.DBDefinition
Autodesk.Revit.DBExternalDefinition

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 25.0.0.0 (25.0.0.0)

Syntax

C++

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public class ExternalDefinition : Definition, 
	IDisposable

Public Class ExternalDefinition
	Inherits Definition
	Implements IDisposable

public ref class ExternalDefinition : public Definition, 
	IDisposable

type ExternalDefinition = 
    class
        inherit Definition
        interface IDisposable
    end

The ExternalDefinition type exposes the following members.

Properties

	Name	Description
	Description	The description of the parameter. The description will be used as tooltip in the Revit UI including in the properties palette.
	GUID	Returns the GUID associated with the shared parameter definition.
	HideWhenNoValue	Indicates whether this parameter should be hidden from the properties palette when it has no value.
	IsValidObject	Specifies whether the .NET object represents a valid Revit entity.
	Name	The user visible name for the parameter. (Overrides DefinitionName)
	OwnerGroup	Returns or change the group ID of the external parameter definition.
	UserModifiable	Indicates whether the parameter can be modified by the user interface.
	Visible	Indicates if the parameter is visible in the Autodesk Revit user interface.

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Methods

	Name	Description
	Dispose	Releases all resources used by the ExternalDefinition
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object)
	GetDataType	Gets a ForgeTypeId identifying the data type describing values of the parameter. (Inherited from Definition)
	GetGroupTypeId	Returns the identifier of the parameter definition's parameter group. (Overrides DefinitionGetGroupTypeId)
	GetHashCode	Serves as the default hash function. (Inherited from Object)
	GetType	Gets the Type of the current instance. (Inherited from Object)
	ToString	Returns a string that represents the current object. (Inherited from Object)

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Remarks

The ExternalDefinition object can be created by a definition Group object from a shared parameters file. External parameter definition must belong to a Group which is nothing more than a collection of shared parameter definitions. The following process should be followed to add a parameter to an element: Open the shared parameters file, via the Application.OpenSharedParameterFile() method. Access an existing or create a new group, via the DefinitionFile.Groups property. Access an existing or create a new external parameter definition, via the DefinitionGroup.Definitions property. Create a new Binding object with the categories to which the parameter will be bound using an InstanceBinding or a TypeBinding object. Finally add the binding and definition to the document using the Document.ParameterBindings object.

Shared parameters added to elements are typically visible to interactive users. To add data to elements that is never visible to interactive users, use Extensible Storage to construct and populate the needed structured data.

Example

C++

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private void ReadEditExternalParam(DefinitionFile file)
{
    // get ExternalDefinition from shared parameter file
    DefinitionGroups myGroups = file.Groups;
    DefinitionGroup myGroup = myGroups.get_Item("MyGroup");
    if (myGroup != null)
    {
         ExternalDefinition myExtDef = myGroup.Definitions.get_Item("MyParam") as ExternalDefinition;
         if (myExtDef != null)
         {
             DefinitionGroup newGroup = myGroups.get_Item("AnotherGroup");
             if (newGroup != null)
             {
                 // change the OwnerGroup of the ExternalDefinition
                 myExtDef.OwnerGroup = newGroup;
             }
         }
    }
}

Private Sub ReadEditExternalParam(file As DefinitionFile)
   ' get ExternalDefinition from shared parameter file
   Dim myGroups As DefinitionGroups = file.Groups
   Dim myGroup As DefinitionGroup = myGroups.Item("MyGroup")
   If myGroup IsNot Nothing Then
      Dim myExtDef As ExternalDefinition = TryCast(myGroup.Definitions.Item("MyParam"), ExternalDefinition)
      If myExtDef IsNot Nothing Then
         Dim newGroup As DefinitionGroup = myGroups.Item("AnotherGroup")
         If newGroup IsNot Nothing Then
            ' change the OwnerGroup of the ExternalDefinition
            myExtDef.OwnerGroup = newGroup
         End If
      End If
   End If
End Sub

Reference

Autodesk.Revit.DB Namespace