RPC HELP Tutorial Step 6

RPC Broker Help Home

Tutorial Home

Tutorial: Step 6 -- Call ZxxxTT LIST RPC

Now that you have created and tested the ZxxxTT LIST RPC on the VistA M Server, you can use your Delphi-based application's TRPCBroker component to call that RPC.

To call the ZxxxTT LIST RPC from your Delphi-based application to populate a list box:

• Place a TListBox component on your form. It should be automatically named ListBox1.
  • Size it so that it uses the full width of the form, and half of the form's height.
• Place a button beneath ListBox1.
  • Set its caption to 'Retrieve Terminal Types'.
  • Size the button so that it is larger than its caption.
• Double-click on the button. This creates an event handler procedure, TForm1.Button1Click, in your Pascal source code.
• In the TForm1.Button1Click event handler, add code to call the ZxxxTT LIST RPC and populate the list box with the retrieved list of terminal type entries. This code should:
  • Set RCPBroker1's RemoteProcedure property to ZxxxTT LIST.
  • Call brkrRPCBroker1's Call method (in a try...except exception handler block) to invoke that RPC.
  • Retrieve results from brkrRPCBroker1's Results property, setting them one-by-one into the list box's Items property.

This code should look as follows:

   Procedure TForm1.Button1Click(Sender: TObject);
   var
     i: integer;
   begin
     brkrRPCBroker1.RemoteProcedure:='ZxxxTT LIST';
     try
       {call begin}
       begin
         brkrRPCBroker1.Call;
         ListBox1.Clear;
         for i:=0 to (brkrRPCBroker1.Results.Count-1) do
           ListBox1.Items.Add(piece(brkrRPCBroker1.Results[i],'^',2));            
       end;  {call end}
     except
       On EBrokerError do begin
         ShowMessage('A problem was encountered communicating with the server.');
       end;
     end;  {try end}
   end;

• Include the mfunstr unit in the Uses clause of your project's Pascal source file. This enables your application to use the piece function included in mfunstr.
• Your user account must have [[RPC_HELP_XUPROGMODE|XUPROGMODE] key assigned. This allows your application to execute any RPC, without the RPC being registered. Later in the tutorial you will register your RPCs.
• Now run your application, and press the Retrieve Terminal Types button. It should retrieve and display terminal type entries, and appear as follows:

   <image missing>

Now that you can retrieve a list of terminal type entries, the next logical task is to retrieve a particular entry when a user selects that entry in the list box.