Object reference not set to an instance of an object.

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hello ,

I'm getting following error " Object reference not set to an instance of an object".
This s the code im using ..could not find image in folder .. ..How to Solve this?

C#

protected void Radbtn_Upload_Click(object sender, EventArgs e)
       {

           string filename = System.IO.Path.GetFileName( FileUpload.PostedFile.FileName);
           FileUpload.SaveAs(Server.MapPath("images/") + filename);

       }

thank you

Posted 13-May-15 22:08pm

Member 11148509

Updated 14-May-15 19:53pm

v5

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Comments

CHill60 14-May-15 4:20am

Use your debugger and check the contents of FileUpload - if it is not null then check the content of FileUpload.PostedFile. Ensure that the object is initialised before the button can be pressed

Member 11148509 14-May-15 4:33am

ya i have done debugging and as u said postedfile is showing null ...

_Asif_ 14-May-15 4:22am

Why can't you debug your code and see the object which turns to be null?

Member 11148509 14-May-15 4:33am

i have already done that was not getting so thought to post here

F-ES Sitecore 14-May-15 4:25am

I'm going to take a punt that your fileupload is inside an UpdatePanel. If so, asp:FileUpload doesn't work inside an UpdatePanel, you need to use something specifically for asynch uploads.

Member 11148509 14-May-15 4:38am

ya its inside updatepanel...can u explain little detailed about asynch uploads???so that i can procedd further

F-ES Sitecore 14-May-15 4:45am

Damn, I'm good :D

There are some asynch file upload controls by Microsoft, if you look at the answer on this thread there is a little on them both and links to them

http://stackoverflow.com/questions/22328064/difference-between-ajaxfileupload-and-asyncfileupload-in-asp-net-ajax-control-to

Or you could use a javascript or jQuery based plug-in, if you google "asynch file upload plugin" you'll find plenty, so pick one you like but it might need more understanding to plug it into your page though as most will come with PHP examples rather than asp.net.

Member 11148509 14-May-15 4:47am

ya k so can i use postback triggers???

Member 11148509 14-May-15 5:57am

actually im getting same error though i place outside of updatepanel

Sascha Lefèvre 14-May-15 6:20am

Please note: You're posting comments to yourself. To your own question. If you want anyone to be notified of your comment, you need to reply to a comment.

Sinisa Hajnal 14-May-15 6:28am

Just find out which control is null and make a check before using it. On FileUpload control there is a flag HasFile you could check before trying to save it. As for moving it out of update panel...do you maybe have master page that also contains UpdatePanel? I've had a situation like that couple of months ago. Took me an hour to find the cause.

Member 11148509 14-May-15 6:33am

ya null is near postedfile.filename...and ya actually im doing this image work in one page and when i navigate to another page i do have update panel...
I have done with same code in another fresh page wherein i got the output.

Sinisa Hajnal 14-May-15 6:41am

:) I'm glad you resolved it. Please add the tag to your question or change the title that says [Solved] your title so that others know.

Herman<T>.Instance 15-May-15 8:03am

Make sure the file is uploaded and received on serverside

Member 11148509 15-May-15 8:19am

ya sure ...can i store fileupload.filename in session ????

Herman<T>.Instance 15-May-15 8:38am

do you check:
if(FileUpload.HasFile) is true?

Member 11148509 15-May-15 8:59am

yes i have checked it's not going inside the loop. since file is not available...

Herman<T>.Instance 15-May-15 8:40am

and in other examples I see:
string filename = Path.GetFileName(FileUpload.FileName);
Because the file isn't UPLOADED at that moment, so you have a NULL value. so: remove 'PostedFile' from your code

Member 11148509 15-May-15 9:04am

ya ya i have removed that and tried but same problem...actualy in my code i have code in ispostback in page load..so when i kept break point and saw..after i click upload it is going to postback and checking and then coming to button click ...with in this time fileupload.filename is unable to maintain state...this is what i have understood..just thinking of solution for this ..hope u got me and suggest me some solution ...can i use session????or postbacktriggers???

Herman<T>.Instance 15-May-15 9:06am

do you use in the Page_Load method the phrase:
if (!Page.Ispostback) ?

Member 11148509 15-May-15 9:23am

im not using this code in ispostback..but have tried that also by keeping (ispostback)==true...so when i click upload its coming near ispostback and checking for the code..but same problem ...fileupload.filename is null...

Herman<T>.Instance 15-May-15 9:37am

check when IsPostback= false, You should be able to get the filename

Member 11148509 15-May-15 9:45am

ya i already have someother code in ispostback==false..that gets executed first ...then after that when page is shown im uploading image and again control is going to ispostback==false ..which wont get executed...so if i keep inside that it wnt get executed...

Herman<T>.Instance 15-May-15 9:15am

postbacktriggers? Are you using the control in an AJAX update panel?

Member 11148509 15-May-15 9:21am

no i just asked im not using in updatepanel

Herman<T>.Instance 15-May-15 9:20am

in an updatepanel you have to use asp:PostBacktrigger to make it work. See here

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