Setting HTML Text Element value

Question

In a C# WPF program I'am trying to set the value of a HTML Text element which is defined:

<input name="tbBName" type="text" id="tbBName" tabindex="1" />

I tried the following:

mshtml.HTMLDocument doc = (mshtml.HTMLDocument)webBrowser1.Document;
mshtml.HTMLInputTextElement tbName = (mshtml.HTMLInputTextElement)doc.getElementsByName("tbBName");
tbName.value = "Test";

But I get the following exception:

Unable to cast COM object of type 'System.__ComObject' to interface type 'mshtml.HTMLInputTextElement'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{3050F520-98B5-11CF-BB82-00AA00BDCE0B}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).

I know what it says but I don't know which object I can use to access the Textbox.

What am I doing wrong?

score 0 · Answer 1 · answered May 16 '10 at 06:43

0

do you know if you using jquery i can tell you its very easy

$('#tbBName').val('value here');

answered May 16 '10 at 06:43

Mostafa Elkady

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Hey moustafa, i don´t have access to the page´s code and i don´t want to write something in jquery. Its a tool to fill the texboxes of the page with values from a excel file. So you have any c# idea? – Gpx May 16 '10 at 06:56

score 0 · Accepted Answer · answered May 16 '10 at 06:55

0

You use the HTML Agility Pack to parse the complete HTML (as received by the WebBrowser control).

You can query it using XPath syntax and it exposes the HTML in a similar manner to the XmlDocument API.

answered May 16 '10 at 06:55

Oded

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Thank you Oded i will have a look at this pack. But isn´t there a simple way with the code that i am trying? – Gpx May 16 '10 at 07:03
@Gpx - not sure. The one thing I did notice is that you are getting a _collection_ (`getElementsByName` returns a collection) and you are trying to force it into a single element. Try selecting the first result. – Oded May 16 '10 at 07:39
On mshtml.HTMLElementCollection collection = (mshtml.HTMLElementCollection)document.getElementsByName("tbName"); i get the same exception. – Gpx May 16 '10 at 08:00
@Gpx - I don't really know. mshtml is old and not very well documented, which is why I suggest using the HTML Agility Pack. – Oded May 16 '10 at 08:04
Thank you for your time Oded, i found an answer from Stan R. in post: http://stackoverflow.com/questions/1133549/mshtml-htmldocumentclass-in-c . I found the element with htmlDoc.all.item("p", 0); Thank you! – Gpx May 16 '10 at 08:09

score 0 · Answer 3 · answered Jun 07 '10 at 20:05

I've found getElementsByName to be unreliable when used directly on the document (using it from C++)

So along with the issue mentioned by Oded about the result being a collection, you may want to try something like the following structure. (untested/outline only)

mshtml.HTMLDocument doc = (mshtml.HTMLDocument)webBrowser1.Document;
mshtml.ElementCollection col = doc.getAll();
Dispatch disp = col.namedItem("tbBName");
// in C++ this can return either a collection or an item
try{ // collection
  mshtml.ElementCollection col2 = (mshtml.ElementCollection)disp;
  for( index = 0; index < col2.length; ++index ) {
    mshtml.HTMLInputTextElement tbName = (mshtml.HTMLInputTextElement)col2[index];
    tbName.value = "Test";
}
try{ // item
    mshtml.HTMLInputTextElement tbName = (mshtml.HTMLInputTextElement)disp;
    tbName.value = "Test";
}

Setting HTML Text Element value

3 Answers3