While uploading file objet reference is not set instance error

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I am uploading File using file Upload control and I have one button to upload it on server but but it gives error at first line in code as

Object reference not set to an instance of an object

I have File upload control as

<asp:FileUpload ID="fileuploadDoc" class="form-control" runat="server" />

also Have server side Validation as

<asp:RequiredFieldValidator ID="RequiredFieldVal" ControlToValidate="fileuploadDoc" runat="server" ErrorMessage="Choose File" ValidationGroup="valProPic" Display="Dynamic" Font-Size="Smaller" ForeColor="#CC0000"></asp:RequiredFieldValidator>
                                <asp:RegularExpressionValidator ID="RegularExpressionValidator6" ControlToValidate="fileuploadDoc" ErrorMessage="Only .png & .jpg images are alloweded" ValidationExpression="([a-zA-Z0-9\s_\\.\-:])+(.png|.jpg)$" runat="server" ValidationGroup="valProPic" Display="Dynamic" Font-Size="Smaller" ForeColor="#CC0000" />

and button as

<asp:LinkButton runat="server" ID="btnaddfileuplod" ValidationGroup="valProPic" CssClass="btn btn-primary" OnClick="btnaddfileuplod_Click">Upload</asp:LinkButton>
                               <asp:LinkButton runat="server" ID="btnDeleteProPic" CausesValidation="false" CssClass="btn btn-default" OnClick="btnDeleteProPic_Click">Delete</asp:LinkButton>

What I have tried:

Uplaod Button as

<asp:LinkButton runat="server" ID="btnaddfileuplod" ValidationGroup="valProPic" CssClass="btn btn-primary" OnClick="btnaddfileuplod_Click">Upload</asp:LinkButton>

On click Handlar as

protected void btnaddfileuplod_Click(object sender, EventArgs e)
    {
        int size1 = fileuploadDoc.PostedFile.ContentLength;
        bool flag = false;
        if (size1 > 0)
        {
            try
            {
                string imgPath = "";
                string filename = Path.GetFileName(fileuploadDoc.PostedFile.FileName);
                string extension = System.IO.Path.GetExtension(fileuploadDoc.FileName);
                imgPath = "img/" + Common.Get_SystemDate_IndianFormate().ToString("ddMMyyhhmmss") + extension;

                fileuploadDoc.SaveAs(Server.MapPath(imgPath));

                flag = true;
                lblUploadedProPicPath.Text = imgPath;
                imgProfile.ImageUrl = imgPath;
            }
            catch (Exception ex) { flag = false; }
        }
        if (!flag)
        {
            AlertMesg(false, "File uploading fail. Please try again...!");
        }
    }

for another page I have Same Button and same code It Working Fine there
but here it is giving exception at first Line

Posted 7-Sep-18 1:59am

paul_vin

Updated 7-Sep-18 3:01am

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F-ES Sitecore 7-Sep-18 9:28am

The FileUpload component doesn't work inside an UpdatePanel

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OriginalGriff · Answer 1 · 2018-09-07T02:08:00

This is one of the most common problems we get asked, and it's also the one we are least equipped to answer, but you are most equipped to answer yourself.

Let me just explain what the error means: You have tried to use a variable, property, or a method return value but it contains null - which means that there is no instance of a class in the variable.
It's a bit like a pocket: you have a pocket in your shirt, which you use to hold a pen. If you reach into the pocket and find there isn't a pen there, you can't sign your name on a piece of paper - and you will get very funny looks if you try! The empty pocket is giving you a null value (no pen here!) so you can't do anything that you would normally do once you retrieved your pen. Why is it empty? That's the question - it may be that you forgot to pick up your pen when you left the house this morning, or possibly you left the pen in the pocket of yesterdays shirt when you took it off last night.

We can't tell, because we weren't there, and even more importantly, we can't even see your shirt, much less what is in the pocket!

Back to computers, and you have done the same thing, somehow - and we can't see your code, much less run it and find out what contains null when it shouldn't.
But you can - and Visual Studio will help you here. Run your program in the debugger and when it fails, VS will show you the line it found the problem on. You can then start looking at the various parts of it to see what value is null and start looking back through your code to find out why. So put a breakpoint at the beginning of the method containing the error line, and run your program from the start again. This time, VS will stop before the error, and let you examine what is going on by stepping through the code looking at your values.

But we can't do that - we don't have your code, we don't know how to use it if we did have it, we don't have your data. So try it - and see how much information you can find out!

Dave Kreskowiak · Answer 2 · 2018-09-07T03:01:00

Like 'Griff said, set a breakpoint on the first line of code in your button click handler. Start looking at the contents of variables and objects and it'll be very easy to find which piece is null.

You cannot use methods or properties of an object that doesn't exist, or is null. You're code is assuming everything is working the way YOU expect. That isn't the case. Now it's up to YOU to use the debugger to understand how your code is really working.

While uploading file objet reference is not set instance error

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