Delphi – Cannot install components that worked under D7 in D2009

I was struggling with this problem for a long time. Changing REFERENCEINFO in package settings from "none" to "definitions only" did the trick. Hope this will help you also.

You can use OpenTools API to get the active project's search path (merged from active configuration and option set) and the IDE's global library path. Here is a unit from my quick test design package:

unit Unit1;

interface

uses
  Windows, SysUtils, Classes,
  ToolsAPI;

type
  TTestWizard = class(TNotifierObject, IOTAWizard, IOTAMenuWizard)
  private
    { IOTAWizard }
    function GetIDString: string;
    function GetName: string;
    function GetState: TWizardState;
    procedure Execute;
    { IOTAMenuWizard }
    function GetMenuText: string;
  private
    function AddLibraryPaths(Strings: TStrings): Integer;
    function AddProjectSearchPaths(Strings: TStrings): Integer;
  end;

procedure Register;

implementation

uses
  Dialogs,
  DCCStrs, TypInfo;

var
  WizardIndex: Integer = -1;

procedure GetEnvironmentVariables(Strings: TStrings);
var
  P: PChar;
begin
  P := nil;
  Strings.BeginUpdate;
  try
    Strings.Clear;
    P := GetEnvironmentStrings;
    repeat
      Strings.Add(P);
      P := StrEnd(P);
      Inc(P);
    until P^ = #0;
  finally
    if Assigned(P) then
      FreeEnvironmentStrings(P);
    Strings.EndUpdate;
  end;
end;

function EvaluateEnvironmentVariables(const S: string): string;
var
  Strings: TStringList;
  I: Integer;
begin
  Result := S;

  Strings := TStringList.Create;
  try
    GetEnvironmentVariables(Strings);
    for I := 0 to Strings.Count - 1 do
      Result := StringReplace(Result, Format('$(%s)', [Strings.Names[I]]), Strings.ValueFromIndex[I],
        [rfReplaceAll, rfIgnoreCase]);
  finally
    Strings.Free;
  end;
end;

procedure Register;
begin
  WizardIndex := (BorlandIDEServices as IOTAWizardServices).AddWizard(TTestWizard.Create);
end;

{ TTestWizard private: IOTAWizard }

function TTestWizard.GetIDString: string;
begin
  Result := 'TOndrej.TestWizard';
end;

function TTestWizard.GetName: string;
begin
  Result := 'TestWizard';
end;

function TTestWizard.GetState: TWizardState;
begin
  Result := [wsEnabled];
end;

procedure TTestWizard.Execute;
var
  Paths: TStrings;
begin
  Paths := TStringList.Create;
  try
    AddProjectSearchPaths(Paths);
    AddLibraryPaths(Paths);
    ShowMessage(EvaluateEnvironmentVariables(Paths.Text));
  finally
    Paths.Free;
  end;
end;

{ TTestWizard private: IOTAMenuWizard }

function TTestWizard.GetMenuText: string;
begin
  Result := GetIDString;
end;

function TTestWizard.AddLibraryPaths(Strings: TStrings): Integer;
var
  Paths: TStringList;
  EnvironmentOptions: IOTAEnvironmentOptions;
begin
  Paths := TStringList.Create;
  try
    Paths.Delimiter := ';';
    Paths.StrictDelimiter := True;
    EnvironmentOptions := (BorlandIDEServices as IOTAServices).GetEnvironmentOptions;
    Paths.DelimitedText := EnvironmentOptions.Values['LibraryPath'];
    Strings.AddStrings(Paths);
    Result := Paths.Count;
  finally
    Paths.Free;
  end;
end;

function TTestWizard.AddProjectSearchPaths(Strings: TStrings): Integer;
var
  ActiveProject: IOTAProject;
  Configurations: IOTAProjectOptionsConfigurations;
  Configuration: IOTABuildConfiguration;
  Paths: TStringList;
begin
  Result := -1;
  ActiveProject := GetActiveProject;
  if not Assigned(ActiveProject) then
    Exit;
  Configurations := ActiveProject.ProjectOptions as IOTAProjectOptionsConfigurations;
  Configuration := Configurations.ActiveConfiguration;
  if not Assigned(Configuration) then
    Exit;

  Paths := TStringList.Create;
  try
    Configuration.GetValues(sUnitSearchPath, Paths, True);
    Strings.AddStrings(Paths);
    Result := Paths.Count;
  finally
    Paths.Free;
  end;
end;

initialization

finalization
  if WizardIndex <> -1 then
    (BorlandIDEServices as IOTAWizardServices).RemoveWizard(WizardIndex);

end.