Collapse Getting StartedGetting Started
Expand Types of SolidWorks API ApplicationsTypes of SolidWorks API Applications
Expand SolidWorks API Object Model and Class HierarchySolidWorks API Object Model and Class Hierarchy
Collapse Programming with the SolidWorks APIProgramming with the SolidWorks API
Expand Add-insAdd-ins
API Dependent on SolidWorks Being Visible
Attributes Imported from ACIS SAT Files
Block Definitions and Block Instances
Bodies in Body Folders
Bounding Box and Note Text
COM vs. Dispatch
CommandManager and CommandGroups
Components, Configurations, and Suppression States
Compound Note
ComVisibleAttribute in VSTA macros
Controls, Visual Basic 6.0, and Windows XP
Expand Double Arrays and Integer PairsDouble Arrays and Integer Pairs
Drawing Views and Model Entities
Early and Late Binding
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Features of Components
Helper Functions
Hole Wizard Features and Objects
IDispatch Object Arrays as Input in .NET
Implementation Guidelines
Import and Export File Options
In-process Methods
Instantiate ActiveX Controls as Tabs
Interface Pointers
Keystrokes and Accelerator Keys
Library Features and Objects
Lightweight Components
Line Attributes for View::GetPolyLinesAndCurves
Line Weights
Long vs. Integer
Expand Macro FeaturesMacro Features
Mass Properties
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Option Explicit Statement
Partition Rollback and API Handles
Persistent Reference IDs
Presentation Transforms
Expand PropertyManager PagesPropertyManager Pages
.NET Interop Assemblies
Quick Tips and Bubble ToolTips
Return Values
Expand SafeArraysSafeArrays
Selection Criteria
Selection Lists
Selections that Define Features
Setup Project to Distribute SolidWorks Add-in
Smart Pointers
SolidWorks Objects
Sorting Tables
STL Container Classes and Smart Pointers
Suspend Automatic Rebuilds
System Options and Document Properties
Tessellation and Edges
Tracking IDs
Expand Type LibrariesType Libraries
Unmanaged C++ and C++/CLI Code
VBA and SolidWorks x64
Examples and Projects
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Return Values

If you are using unmanaged C++ COM, the SolidWorks API function always returns an HRESULT. Any additional return values should be passed by reference as arguments.

SolidWorks uses HRESULT return values to indicate that the code was called successfully. It is not meant as an indication that your call achieved its objective. For example, calling IBody2::IGetFirstFace will have an HRESULT return value of S_OK if the code for IBody2::IGetFirstFace was called successfully. It does not mean that the code succeeded in finding the first face. In this case, you should check the LPFACE2 return value for a NULL condition.

Object Return Values

If an API method returns an object, it is always a good idea to verify that the object returned is not NULL. This type of error checking is good programming practice and avoids crashes in your code for unexpected conditions. For example:


// In unmanaged C++ (COM)


HRESULT hres = m_PartDoc->IBodyObject(&m_Body); // Get body object from the part

if (m_Body == NULL) return;


hres = m_Body->IGetFirstFace(&m_Face);  // Get first face object from the body

while (m_Face != NULL)     // While faces exist, traverse them


double theFaceArea = 0.0;

hres = m_Face->GetArea(&theFaceArea);  // Sample use of face object pointer


LPENTITY m_Entity = NULL;    // Obtain pointer to Entity object

hres = m_Face->QueryInterface( IID_IEntity, (LPVOID*)&m_Entity);

if (m_Entity != NULL)



hres = m_Entity->Select(TRUE,&boolres); // Sample use of entity object pointer

m_Entity->Release();    // Release Entity object pointer



LPFACE pnextFace = NULL;

m_Face->IGetNextFace(&pnextFace);   // Get the next face object

m_Face->Release();     // Release previous object pointer

m_Face= pnextFace;

}        // End while faces exist


m_PartDoc->Release();     // Release all pointers when done

m_Body->Release();     // Good idea to check for NULL if not certain




// In unmanaged C++ (Dispatch)

LPDISPATCH bodyDisp = m_PartDoc.Body();  // Get body object from the part

if (bodyDisp == NULL) return;

IBody m_Body(bodyDisp);


LPDISPATCH faceDisp = m_Body.GetFirstFace(); // Get Dispatch pointer to first face

while (faceDisp)      // While faces exist, traverse them


IFace m_Face(faceDisp);    // Get the Face member

double theFaceArea = m_Face.GetArea();  // Sample use of face object pointer


IEntity m_Entity(faceDisp);    // Obtain pointer to entity object

faceDisp->AddRef();     // Manually increment the reference count


boolean retval = m_Entity.Select(TRUE);   // Sample use of entity object pointer


faceDisp = m_Face.GetNextFace();   // Get the next face


}      // End while faces exist

      // Objects go out of scope and ref count decremented in destructor




' In Visual Basic for Applications (VBA)

Dim FaceObj,BodyObj As Object

Dim theFaceArea As Double

Dim ok As Boolean


Set BodyObj = PartObj.Body   ' Get body object from the part

' PartObj represents PartDoc interface - possibly obtained

' using ActiveDoc, OpenDoc, NewPart, etc. functions

If (BodyObj Is Nothing) Then

swApp.SendMsgToUser "Error! Part has no body."

Exit Sub

End If


Set FaceObj = BodyObj.GetFirstFace  ' Get first face from the body object

While Not FaceObj Is Nothing   ' While faces exist, traverse them


theFaceArea = FaceObj.GetArea  ' Sample use of face object pointer


ok = FaceObj.Select(True)   ' Sample use of entity object pointer

' Face object can be used for entity object calls

Set FaceObj = FaceObj.GetNextFace ' Get the next face


Wend      ' End while faces exist


Set BodyObj = Nothing   ' Clean up variables

Set FaceObj = Nothing

Set PartObj = Nothing


VARIANT Return Values

SolidWorks might also return an empty or NULL VARIANT. It is also good programming practice to check for this condition. The following unmanaged C++ and VBA examples show you one method of checking for an empty VARIANT:


// In unmanaged C++

VARIANT v = m_ModelDoc.GetMassProperties();  // Get the mass properties

If ((v.vt == VT_EMPTY) || (V_VT(&v) == VT_NULL)) // Error occurred




' In Visual Basic for Applications (VBA)

PickPt = m_SelectionManager.GetSelectionPointInSketchSpace(1)  ' Get the user's pick point

If (IsEmpty(PickPt) Or IsNull(PickPt)) Then    ' No pick point available

Exit Sub

End If


SafeArray Return Values

The SolidWorks API passes and returns all SafeArrays as a type VARIANT. In many instances, you might find it useful to know the length of a SafeArray returned by SolidWorks. If SolidWorks does not provide a function that counts, such as IFace2::GetEdgeCount, you can use standard MFC or VBA routines to determine the SafeArray length. The following unmanaged C++ and VBA examples show you one way for determining the number of elements in a SafeArray.


// In unmanaged C++

// Get all of the children components from this m_Component object

VARIANT componentChildren = m_Component.GetChildren();

if ((componentChildren.vt == VT_EMPTY) ||

(V_VT(&componentChildren) == VT_NULL)) // Error - array is empty or null


SafeArray* psa = V_ARRAY(&componentChildren);

LPDISPATCH* componentChildrenArray;

HRESULT hres = SafeArrayAccessData(psa, (void **)&componentChildrenArray);


long highIndex;

SafeArrayGetUBound(psa, 1, &highIndex); // Get index number of highest array element

       // The array range is from 0 to highIndex

long childrenCount = highIndex + 1;  // Actual # of array elements is highIndex + 1

for (int i = 0; i < childrenCount; i++) // For each child component


IComponent m_childComponent(componentChildrenArray[i]);



VARIANT_BOOL isSuppressed;   // Perform sample operation using the component

isSuppressed = m_childComponent.IsSuppressed();


hres = SafeArrayUnaccessData(psa);  // Release and destroy the

hres = SafeArrayDestroy(psa);   // component SafeArray



' In VBA

' Display the entire version history for the specified file

' Show results in a list box control

Dim fileHistory As Variant

fileHistory = swApp.VersionHistory(filename)

If Not (IsEmpty(fileHistory) Or IsNull(fileHistory)) Then 

For i = 0 To UBound(history)   ' For each string in the SafeArray,

myListBox.AddItem (fileHistory(i))  ' Display it in the list box control

Next i

End If


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