TWebBrowser QueryInterface IID_IHTMLElement2 always returns E_NOINTERFACE

151 Views Asked by Coder12345 At 28 May 2021 at 22:47

I am doing a simple QueryInterface() to get the IHTMLElement2 interface, but it always fails with E_NOINTERFACE.

UPDATE: I need to get the IHTMLElement2 interface of the body element because it has a focus() method so I can set focus to the body. It can't be done with the IHTMLElement interface.

Any ideas why this errors (or how to reach body->focus())?

WebBrowser1->Navigate(L"c:\\test.htm");
while (WebBrowser1->Busy) Application->ProcessMessages();

DelphiInterface<IHTMLDocument2> diDoc = WebBrowser1->Document;
if (diDoc) {
    DelphiInterface<IHTMLElement2> diBodyElement;

    // all good until this point
    if (SUCCEEDED(diDoc->QueryInterface(IID_IHTMLElement2, reinterpret_cast<void**>(&diBodyElement))) && diBodyElement) {
        // Never reaches this part - always E_NOINTERFACE when querying for IID_IHTMLElement2
        diBodyElement->focus();
        }
    }

Original Q&A

There are 1 best solutions below

Coder12345 On 29 May 2021 at 11:50 BEST ANSWER

I've reached my own solution how to reach body->focus() which follows:

DelphiInterface <IHTMLDocument2> diDoc2 = WebBrowser1->Document;

if (diDoc2) {
    DelphiInterface<IHTMLElement>     pBody1;
    DelphiInterface<IHTMLElement2>    pBody2;
    DelphiInterface<IHTMLBodyElement> pBodyElem;

    if (SUCCEEDED(diDoc2->get_body(&pBody1)) && pBody1) {
        if (SUCCEEDED(pBody1->QueryInterface(IID_IHTMLBodyElement, reinterpret_cast<void**>(&pBodyElem))) && pBodyElem) {
        if (SUCCEEDED(pBodyElem->QueryInterface(IID_IHTMLElement2, reinterpret_cast<void**>(&pBody2))) && pBody2) {
            pBody2->focus();
            }
        }
    }
}

EDIT (suggested by Reby Lebeau) - simplified version:

DelphiInterface <IHTMLDocument2> diDoc2 = WebBrowser1->Document;

if (diDoc2) {
    DelphiInterface<IHTMLElement>  pBody1;
    DelphiInterface<IHTMLElement2> pBody2;

    if (SUCCEEDED(diDoc2->get_body(&pBody1)) && pBody1) {
        if (SUCCEEDED(pBody1->QueryInterface(IID_IHTMLElement2, reinterpret_cast<void**>(&pBody2))) && pBody2) {
            // focus to <body> element
            pBody2->focus();
            }
        }
    }

TWebBrowser QueryInterface IID_IHTMLElement2 always returns E_NOINTERFACE

There are 1 best solutions below

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