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Ian Boyd
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 Posted: Thu Sep 07, 2006 12:53 am Post subject: Possible to call a dispatch interface with the method name i |
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Consider
procedure DoStuff(o: OleVariant; doc: IXMLDOMDocument2)
var
MethodName: string;
Param1, Param2: string;
begin
MethodName := doc.selectSingleNode('/body/foo/method');
Param1 := doc.selectSingleNode('/body/foo/param1');
Param2 := doc.selectSingleNode('/body/foo/param2');
o.MethodName(Param1, Param2);
end;
Problem here is that it will try to call a method named "MethodName" rather
than a method name contained in the MethodName variable.
i know i could use
o.GetIDsOfNames(...)
and pass it MethodName and get it's DispID, but then when calling Invoke i
would be faced with having to figure out how to marshall all the parameters
into those horribly scary parameters of Invoke.
i cannot imagine a syntax for such an animal, except possibly
procedure DispatchInvoke(const MethodName: string; const params: array
of OleVariant);
Was such a thing already written for me? |
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Chris Cheney
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| Posted: Tue Sep 12, 2006 5:13 pm Post subject: Re: Possible to call a dispatch interface with the method na |
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"Ian Boyd" <ian.borlandnews010 (AT) avatopia (DOT) com> wrote in
news:44ff2735 (AT) newsgroups (DOT) borland.com:
| Quote: | Consider
procedure DoStuff(o: OleVariant; doc: IXMLDOMDocument2)
var
MethodName: string;
Param1, Param2: string;
begin
MethodName := doc.selectSingleNode('/body/foo/method');
Param1 := doc.selectSingleNode('/body/foo/param1');
Param2 := doc.selectSingleNode('/body/foo/param2');
o.MethodName(Param1, Param2);
end;
Problem here is that it will try to call a method named "MethodName"
rather than a method name contained in the MethodName variable.
i know i could use
o.GetIDsOfNames(...)
and pass it MethodName and get it's DispID, but then when calling
Invoke i would be faced with having to figure out how to marshall all
the parameters into those horribly scary parameters of Invoke.
i cannot imagine a syntax for such an animal, except possibly
procedure DispatchInvoke(const MethodName: string; const params:
array
of OleVariant);
Was such a thing already written for me?
|
This is code that I use to Invoke with one parameter, but modified for two
parameters:
uses
ActiveX, ComObj;
var
TheLcid: Integer; // set to the LCID
function GetDispId(const Obj: IDispatch; const Member: WideString; var
TheDispId: Integer): Boolean;
begin
Result := Succeeded(Obj.GetIdsOfNames(GUID_NULL, @Member, 1, TheLcid,
@TheDispId));
end;
function InvokeMember(const Obj: IDispatch; const Member: WideString; Arg1,
Arg2: OleVariant; DispatchFlags: Word): IUnknown;
var
TheDispId, ArgErr: Integer;
TheDispParams: TDispParams;
Params: array[0..1]of OleVariant; // NB in reverse order
varResult: Variant;
begin
Result := nil;
if GetDispId(Obj, Member, TheDispId) then
begin
with TheDispParams do
begin
rgvarg := @Params;
rgdispidNamedArgs := nil;
cArgs := 2;
cNamedArgs := 0;
end;
Params[0] := Arg2;
Params[1] := Arg1;
OleCheck(Obj.Invoke(TheDispId,
GUID_NULL,
TheLcid,
DispatchFlags, // DISPATCH_METHOD,
DISPATCH_PROPERTYGET, ...
TheDispParams,
{$IFDEF Delphi6Up}Result{$ELSE}@Result{$ENDIF},
nil,
{$IFDEF Delphi6Up}ArgErr{$ELSE}@ArgErr{$ENDIF}));
Result := IUnknown(varResult);
end;
end;
HTH |
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Ian Boyd
Guest
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| Posted: Wed Sep 13, 2006 12:12 am Post subject: Re: Possible to call a dispatch interface with the method na |
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| Quote: | This is code that I use to Invoke with one parameter, but modified for two
parameters:
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i see. So you actually do put together all the scary parameter stuff... |
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