ArcObjects Library Reference (SystemUI)  

ICommand.HelpContextID Property

The help context ID associated with this command.

[Visual Basic .NET]
Public ReadOnly Property HelpContextID As Integer
public int HelpContextID {get;}
HRESULT get_HelpContextID(
  long* helpID


helpID [out, retval]   helpID is a parameter of type long

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.


The HelpContextID property is used to specify the mapped numeric value of the topic ID of the context sensitive help topic for your custom command. Specify the name of your help file in the HelpFile property.


If you set both the HelpFile and HelpContextID properties, then an end-user of your command can use the "What's This?" command in ArcMap or ArcCatalog to get help on your command. Note, if you want your What's This help to look and behave the same as the standard ArcGIS commands, then you should create a WinHelp file instead of a HTMLHelp file.

If you have a WinHelp file (*.hlp), set ICommand_HelpFile to the name of the help file containing the topic that describes the command and set ICommand_HelpContextID to the topic ID's mapped numeric value. The topic ID is the so-called # footnote in the RTF file you include in your WinHelp file. You can use Help Workshop to add this numeric value by opening the HPJ file, clicking Map and then clicking Add (to add the mapping for an individual topic). See the help topic "To enable a program to display an individual Help topic" in the Help Workshop's help file.

If you have an HTMLHelp file (*.chm) the procedure is similar; specifiy the
.chm file as ICommand_HelpFile and the mapped numeric value as
ICommand_HelpContextID. Popup topics are problematic with HTMLHelp, but the help topic will display in a default or user-defined window.

As part of your deployment strategy register the name of the WinHelp file (*.hlp) as a new string value in:

Or if you're working with a HTMLHelp file (*.chm) register its name as a new string value in:

See Also

ICommand Interface | ICommand.HelpFile Property