IDesignerToolboxSite::AddControl

Requests that the host add an ActiveX control to the toolbox.

HRESULT AddControl (
   REFCLSID rclsid
);

Parameter

rclsid

[in] Class ID of the control to add.

Return Values

The return value obtained from HRESULT is one of the following:

Comments

A designer that hosts ActiveX controls can call AddControl to inform its site about ActiveX controls currently on the designer or ActiveX controls that are useful to the designer. The host needs to know which controls are present so it can display the control's bitmap in the toolbox and add a reference to the control. Adding a reference in this manner is the equivalent of using the Components dialog on the Project menu in Visual Basic.

The designer calls this method in the following situations:

• When the designer is loaded, it calls AddControl for each ActiveX control it contains. Note, however, that if the value of the DISPID_AMBIENT_INTERACTIVE property is FALSE, the designer need not call the method because the designer instance is only temporary.
  
  
• Whenever a user drops a control onto the designer, the designer calls AddControl to ensure that the host adds the control to the toolbox. If the control is already in the toolbox, no error occurs.
  
  
• When the designer needs to make an ActiveX control available for use in the project, it calls AddControl to place that control in the host's toolbox. This method is the only way a designer can add a control for general use; all its toolbox items specified under the DesignerToolbox registry subkey are intrinsic designer-specific controls.

Controls added with this method appear on the General toolbox tab in Visual Basic 6.0, not on the designer's own tab (if it has one).

Example

The following code fragment queries for the IDesignerToolboxSite interface in the SDesignerToolboxSite service, then calls AddControl to add the control with class ID rclsid.

hr = pServiceProvider->QueryService(SID_DesignerToolboxSite,
   IID_IDesignerToolboxSite, (void **)&piToolboxSite);
if (FAILED(hr)) return;
hr = piToolboxSite->AddControl(rclsid);
if (FAILED(hr)) return;