Object reference not set to an instance of an object

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i have created a windows app in c# it loads a web page from a site that contains image. there is a button at the side of the app. when i click on the button it calls a method which get the div tag of in which the image exists and save it as bmp on local drive. but when i click on the button it gives the following error.

Object reference not set to an instance of an object.

C#

if (web != null)
{
    HtmlElement elems = web.Document.GetElementById("recaptcha_image")
}

please tell me what i need to do.

Posted 23-Feb-12 11:06am

saifullahiit

Updated 23-Feb-12 11:36am

Mohammad A Rahman

v3

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2 solutions

Solution 1

I do not know which line you have the exception thrown but you shoud use the magic tool called: Debugger. Put a breakpoint to your if statement check the value of web and elems values. One of them should be null because of that you get that exception. If you have the exception on elems this means that there is no control named "recaptcha_image".

What does object reference not set to an instant of an object mean?[^]

Good luck,
OI

Posted 23-Feb-12 11:31am

Orcun Iyigun

Updated 23-Feb-12 11:33am

v2

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Bernhard Hiller · Accepted Answer · 2012-02-23T21:29:00

Solution 2

You must also check for Document to be not null:

C#

if (web != null)
{
    if (web.Document != null)
    {
        HtmlElement elems = web.Document.GetElementById("recaptcha_image")
    }
}

Posted 23-Feb-12 21:29pm

Bernhard Hiller