COM Exception "Bad Variable Type" Error in Delphi Call of Domino GetDocumentByKey Method

Question

I have a legacy Delphi 2 application that I need to convert from communicating with Notes via OLE Automation to communicating via COM early binding. I am using Delphi 7 since the code base is large and I want to avoid the work of dealing with the Unicode support in the more current versions of Delphi.

The basics are working: the program opens the database then the view and searches for a particular document using the NotesView.GetDocumentByKey method. The GetDocumentByKey call works when the first parameter is a single string cast to an OleVariant as shown below (opening of DB and view not shown).

var
  Key: OleVariant;
const ExactMatch: WordBool = True;
begin
  Key := 'AKeyValue';
  Doc := View.GetDocumentByKey(Key, ExactMatch);

The bad variable type error occurs when the first parameter is a variant array as required when it is desired to search the view based on multiple columns as shown below.

var
  TwoKeysV: OleVariant;
const ExactMatch: WordBool = True;
begin
  TwoKeysV := VarArrayCreate([0, 1], varOleStr);
  TwoKeysV[0]:= WideString('Key1');
  TwoKeysV[1]:= WideString('Key2');
  Doc := View.GetDocumentByKey(TwoKeysV, ExactMatch);

I have tried several variations on the two key assignment statements with no success. For example, just assigning the key string without a cast still produces the bad variable type, and using the StringToOleString function is rejected by the compiler as an invalid assignment (PWideChar to Variant).

In the help array of string is what you need to send, did you try to create a real array of string in Delphi and casting it to OleVariant ? (www-01.ibm.com/support/knowledgecenter/SSVRGU_9.0.1/…) NB this is not what the Help indicates: If this method is used under COM, with a keyArray parameter of an array, it must be defined as an array of type Variant. — Emmanuel Gleizer
Tried the idea of creating the key array is a normal Variant and then casting to OleVariant but it produces the same bad variable type error — Keeloid

Emmanuel Gleizer Emmanuel Gleizer · Accepted Answer · 2015-11-25T06:19:21

I can't test this, so I'm not sure this works.

HELP: If this method is used under COM, with a keyArray parameter of an array, it must be defined as an array of type Variant

So you need to pass: an array of type Variant

Based on How to use variant arrays in Delphi.

Note: Code edited by Keeloid to match code that worked by casting key string to WideString.

var
  TwoKeysV: OleVariant;
const ExactMatch: WordBool = True;
begin
  TwoKeysV := VarArrayCreate([0, 1], varVariant);
  TwoKeysV[0]:= WideString('Key1');  {WideString = varOleStr}
  TwoKeysV[1]:= WideString('Key2');
  Doc := View.GetDocumentByKey(TwoKeysV, ExactMatch);

COM Exception "Bad Variable Type" Error in Delphi Call of Domino GetDocumentByKey Method

1 Answers