Creating custom command objects and registering them globally within the DWGdirect runtime environment allow a custom DWGdirect DRX application to create commands that clients of the DRX application can use.

DWGdirect maintains a global command stack of type OdEdCommandStack that stores custom commands the client applications create. The odedRegCmds function can access the global stack.

An OdEdCommandStack stores CFxCommand objects. A CFxCommand has the following attributes:

Global name
The global name is the non-localized version of the command name.
Local name
The local name represents the localized version of the command name.
Group name
The group name provides a mechanism to group sets of commands together within the stack, where a group can access them using the OdEdCommand::newGroupIterator() function.
Help-ID
The help-ID is used as a mechanism to provide a command specific help.

CFxCommand also contains exception handling and a virtual Execute function, which is called to execute the command.

When a command is executed, an instance of CFxCommandContext is passed to the command Execute() function, thus providing access to the current database and to an I/O interface that can be used to implement interactive commands.

Example of Creating a Custom Command

Here is an example of a simple CFxCommand Subclass. When executed, this object retrieves a string value from the passed in I/O object and writes this string back out.

class SampleCmd : public OdStaticRxObject < CFxCommand >
{
public:
  const OdString  localName() const { return globalName(); }
  const OdString  groupName() const { return "ODA Example Commands"; }
  const OdString  globalName() const { return OdString("SampleCommand"); }

  // Body of the custom command.
  int Execute( CFxCommandContext* pCmdCtx )
  {
    CFxUserIO* pUserIO = pCmdCtx->GetFxDocument()->GetFxUserIO(); // User IO object from command context
    CFxDatabase* pDB = pCmdCtx->GetFxDocument()->GetFxDatabase(); // Current database
    
    CFxString sKey = L"< default >";
    CFxString sPrompt = pUserIO->GetPromptString( L"Enter a value: ", &sKey );
    pUserIO->GetString( true, sPrompt, sKey, &sKey );
    pUserIO->Write( sKey + " was entered" );
  }
};

Custom commands can peform database operations, such as creating new objects, query for input, and operations based on that input.

Registering a Custom Command

A custom command is registered using the OdEdCommandStack::addCommand function on the global command stack:

  SampleCmd command; // must not be destroyed while the command exists in the global stack
  odedRegCmds()->addCommand(& command);

Since addCommand takes a pointer, the passed in command object must not be destroyed until the command is removed from the global stack at some later point.

ARES Commander Partner Documentation

Creating Custom Commands

Example of Creating a Custom Command

Registering a Custom Command