Gregory Koehn

Quote

Luckily, TMS XData does support Swagger beautifully, and in a very automatic way.

Source of this information...

https://landgraf.dev/en/graphql-from-the-perspective-of-a-delphi-developer/

Oops! Sorry! The quote is about Swagger not GraphQL.

Here is another link of Delphi GraphQL component...

https://github.com/bogdanpolak/graphql-delphi

Disclaimer. I have no experience with this component!

Thanks for the info!

I guess I was looking for something a bit more RAD and visual.

For any new Delphi developer coming along, They may want to use the "type library editor".

Does anyone have up-to-date tutorials regarding creating it in the "type library editor"?

For example the Delphi Com Client code should be able to access it like...

This is not actual syntactically correct code! Just here for illustration...

uses
  ComObj
  ;

procedure TForm1.Button1Click(Sender: TObject);
var
  ComServer: OleVariant;
  Item: OleVariant;
  i : Integer;
  countOfItems: Integer;
begin
  ComServer := CreateOleObject('ComServer.GregsComServer');
  countOfItems := ComServer.Store.ItemsCount();
  for i := 0 to countOfItems-1 do
    begin
      Item := ComServer.Store.Items(i);
      Showmessage(Item.Name);
      Showmessage(inttostr(Item.InStockCount));
    end;
  ComServer := null;
end;

No need to waist time on me... Just if someone is bored and wants some ideas to publish an article about the RAD of Delphi...

It would be great if someone would write a simple tutorial on Windows Com using Delphi 10.Latest!

Maybe do a video and put it on YouTube.

I would like to learn how to create a com object method that returns another com object.

For example...

Com Object Name = "Store"

"Store" has a method that returns Com Object "Item".

"Item" has a string property of "Name".

"Item" has a int property of "InStockCount".

I can't take the time right now to learn all this by going through pages and pages of internet sites that were written for Delphi 5.

For now I will just put data into a string array and parse it in the consumer.

What I am actually doing is wrapping a 32-bit DLL, provided by another company, in a Com Server, so we can access it by using our 64-bit program.

You know how it is in real life... Get it done as soon as possible!!!

I don't want you to do my work for me... It would be good info for future seekers to find and use!

I got it to work!!!

See ParameterDesign.png attached...

You cannot send it as a result but as an "out" parameter!

Here is my Server "Code Behind" of "Method2"...

procedure TGregsComServer.Method2(out MyVariantArray: OleVariant);
begin
  MyVariantArray := VarArrayCreate([0, 1], varOleStr);
  MyVariantArray[0] := 'Hello';
  MyVariantArray[1] := 'World';
end;

Here is my Delphi Consumer code now...

procedure TForm1.Button2Click(Sender: TObject);
var
  ComServer: OleVariant;
  vUDTArray: OleVariant;
  i : Integer;
  value : String;
begin
  ComServer := CreateOleObject('ComServer.GregsComServer');
  ComServer.Method2(vUDTArray);
  if VarIsArray(vUDTArray) then
    begin
      if VarIsByRef(vUDTArray) then
        ShowMessage('varisbyref');
      for i := VarArrayLowBound(vUDTArray, 1) to VarArrayHighBound(vUDTArray, 1) do
        begin
          Value := vUDTArray[i];
          ShowMessage(Value);
        end;
    end;
  ComServer := null;
end;

Thanks for your help Anders! Good to see you are still producing Delphi code!

And here is my simple Delphi consumer...

uses
  ComObj
  ;

procedure TForm1.Button1Click(Sender: TObject);
var
  ComServer: OleVariant;
  vUDTArray: OleVariant;
  i : Integer;
  value : String;
begin
  ComServer := CreateOleObject('ComServer.GregsComServer');
  vUDTArray := ComServer.Method1;
  if VarIsArray(vUDTArray) then
    begin
      if VarIsByRef(vUDTArray) then
        ShowMessage('varisbyref');
      for i := VarArrayLowBound(vUDTArray, 1) to VarArrayHighBound(vUDTArray, 1) do
        begin
          Value := vUDTArray;
          ShowMessage(Value);
        end;
    end;
  ComServer := null;
end;

end. 

I just created a fresh ComServer project in Delphi 10.3.

I did New | VCL Application

Then did File | New | Other... | Individual Files | Automation Object

See 1st-step.png

Then Created a Method in the ridl editor like this...

See 2nd-step.png

Then registered it "Current User".

See 3rd-step.png

Complete code is in the attached zip file.

When actually calling this method is when the error pops up.

It only happens when calling it from a COM Client.

Compilation works fine.

How can I get this to work? It very well could be just a simple thing I am doing wrong...

ComServerTest.zip

Anders, Good to hear from you!

Here is what Delphi gives me...

See attached png file.

I just can't get peoples examples on the internet to work when actually running it in Delphi IDE!

Has the compiler changed? Does it have a bug?

I just want to be able to assemble an array of string values and return them using COM automation to Python.

I have been successful in returning an array of integers by using this code...

function TGridInfo.GetIntArray: PSafeArray;
var
  ArrayBounds : TSafeArrayBound;
  i : integer;
  ArrayData : pointer;
  lElemCount: integer;
  type
    IntegerArray = Array of integer;
begin
  lElemCount := 11;
  ArrayBounds.lLbound := 0;
  ArrayBounds.cElements := lElemCount;
  result := SafeArrayCreate( varInteger, 1, @ArrayBounds );
  if SafeArrayAccessData( result, ArrayData ) = S_OK then
    begin
      for i:= 0 to lElemCount-1 do
        begin
          IntegerArray(ArrayData)[i]:= i;
        end;
      SafeArrayUnAccessData(result);
    end;
end;

I then try to convert this to String Array...

function TGridInfo.GetStringArray: PSafeArray;
var
  ArrayBounds : TSafeArrayBound;
  i : integer;
  ArrayData : pointer;
  lElemCount: integer;
  type
    StringArray = Array of widestring;
begin
  lElemCount := 11;
  ArrayBounds.lLbound := 0;
  ArrayBounds.cElements := lElemCount;
  result := SafeArrayCreate( VT_BSTR, 1, @ArrayBounds );
  if SafeArrayAccessData( result, ArrayData ) = S_OK then
    begin
      for i:= 0 to lElemCount-1 do
        begin
          StringArray(ArrayData)[i]:= 'element ' + inttostr(i);
        end;
      SafeArrayUnAccessData(result);
    end;
end;

This returns some strange numbers to Python instead of strings.

This also returns strange numbers to Delphi instead of strings.

Here is my Delphi reading code...

implementation

{$R *.dfm}

uses
  ComObj
  ;

procedure TForm1.Button1Click(Sender: TObject);
var
  ComServer: OleVariant;
  vUDTArray: OleVariant;
  i : Integer;
  value : String;
begin
  ComServer := CreateOleObject('Project1.GridInfo');
  vUDTArray := ComServer.GetStringArray;
  if VarIsArray(vUDTArray) then
    begin
      for i := VarArrayLowBound(vUDTArray, 1) to VarArrayHighBound(vUDTArray, 1) do
        begin
          Value := vUDTArray[i];
          ShowMessage(Value);
        end;
    end;
  ComServer := null;
end;

end.

Help me out! I cannot get this figured out.

function TGridInfo.Method4: OleVariant;
var
  I: integer;
  ListItemCount: integer;
  gklist: tstringlist;
  V: OleVariant;
 begin
  gklist := tstringlist.Create;
  try
    gklist.Add('hello');
    gklist.Add('world');
    ListItemCount := gklist.Count;
    //V := VarArrayCreate([0,ListItemCount-1], VT_BSTR);  //<-- This does not work gives error on result := V;
    //V := VarArrayCreate([0,ListItemCount-1], VT_LPWSTR); //<-- errors here.
    V := VarArrayCreate([0,ListItemCount-1], varVariant); //<-- This does not work either gives error on result := V;
    for I := 0 to ListItemCount-1 do
      V[I]:=gklist[I];
    result := V;
  finally
    gklist.Free;
  end;
end;

I am using Delphi 10.3.

Notice my comments in source code as to the problems I have been having.

I am using Python 3.8 to test this system

from win32com import client
com_object = client.Dispatch("Project1.GridInfo")
res = com_object.Method4()
print(res)
com_object = None