Object reference not set to an instance of an object in VS 2010

Question

I'm working with SQL Server 2008R2 and VS 2010

I kept getting this error when I browse I tried opening every page but the same error pops up. Please explain briefly and in simple word what should I do I'm new to this.

[NullReferenceException: Object reference not set to an instance of an object.]

MyProject.login1.ImageButton3_Click(Object sender, ImageClickEventArgs e) in C:\Users\prakash\Desktop\MyProject R2\MyProject R2\MyProject\login1.aspx.cs:26 System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +115 System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +124 System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +35 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1724

Source Code

protected void ImageButton3_Click(object sender, ImageClickEventArgs e)
    {
        int flag = 0;
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["shopingConnectionString1"].ConnectionString);
        string s = "select * from login";
        SqlCommand com = new SqlCommand(s, con);
        con.Open();
        if (con.State == ConnectionState.Open)
        {
            SqlDataReader dtr;
            dtr = com.ExecuteReader();
            while (dtr.Read())
            {
                if (dtr[0].ToString().Equals(TextBox1.Text) && dtr[1].ToString().Equals(TextBox2.Text))
                {


                    Response.Cookies["uname"].Value = TextBox1.Text;
                    Response.Cookies["pwd"].Value = TextBox2.Text;
                    Response.Cookies["role"].Value = dtr[2].ToString();
                    FormsAuthentication.RedirectFromLoginPage(TextBox1.Text, false);

                }
                else
                {
                    Label1.Text = "your credential are incorrect";
                }

That error gives you the line of code and the file. Please post it. — valverij, Feb 06 '14 at 11:07
to be more specific post the code that deals with imagebutton, what value you are passing with image buttong — Amarnath Balasubramanian, Feb 06 '14 at 11:10
prakash, post the login1.aspx.cs code... you have posted login1.aspx code — Sarvesh Mishra, Feb 06 '14 at 11:13
not the design code..!! Please post your backend coding for this.. To make it clear double click on the ImageButton3 you will be taken the code file, post that code here..! — Amarnath Balasubramanian, Feb 06 '14 at 11:17
Sorry for posting the wrong code now I posted the right one. Please check and let me know. — Bohemia, Feb 06 '14 at 11:18
Gosh. That is horrible! You are bringing back the entire table and looping through it to check the username and password. No hashing of passwords. No separation of concerns. — Martin Smith, Feb 06 '14 at 11:20
Keep a break point and by pressing F11 check the exact line where you're getting error.! — Amarnath Balasubramanian, Feb 06 '14 at 11:20
@AmarnathBalasubramanian I didn't get your point? What do I do? — Bohemia, Feb 06 '14 at 11:24
Keep a breakpoint in the line protected void ImageButton3_Click(object sender, ImageClickEventArgs e) and press F11 and by pressing it again again you will see the line where you get error.! — Amarnath Balasubramanian, Feb 06 '14 at 11:26
When I tried to Debug this time the following error shows up in Source Error. Error is on LINE 6 Line 4: Line 5: User Name
Line 6: Line 7: — Bohemia, Feb 06 '14 at 11:27
do you have TextBox1_TextChanged code in your file?? double click in textbox1 and check with that — Amarnath Balasubramanian, Feb 06 '14 at 11:29
Yes I do have the code in my file. And there's no error in that. Plus this error is showing in every page of my project. Whichever page I browse same error pops up. — Bohemia, Feb 06 '14 at 11:32
Try commenting out those lines and run..!! I am unable to reproduce the error. as it is too broad and very hard to find it — Amarnath Balasubramanian, Feb 06 '14 at 11:33
Can you please help me through TeamViewer Sir please? I have to submit this project tomorrow and It's 300 marks project. please. — Bohemia, Feb 06 '14 at 11:35
Did you read the duplicate? Instead of waiting for one of us to give you the fish you could have caught it yourself by now. — Martin Smith, Feb 06 '14 at 11:35
@MartinSmith I did read duplicates before posting it here. I have been doing this from last night. I'm a beginner to coding that's why I'm having so much trouble. I'm sorry. — Bohemia, Feb 06 '14 at 11:37
I agree.. The Null Reference question gives a general solution, this is a question on a specific solution. This is not duplicate. So what's on line 26? — Emanuele Greco, Feb 06 '14 at 11:38
no: the error is still this "MyProject.login1.ImageButton3_Click(Object sender, ImageClickEventArgs e) in C:\Users\prakash\Desktop\MyProject R2\MyProject R2\MyProject\login1.aspx.cs:26 " here it's saying that error is in login1.aspx.cs not in login1.aspx, line 26 — Emanuele Greco, Feb 06 '14 at 11:40
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["shopingConnectionString1"].ConnectionString); This was on Line26 — Bohemia, Feb 06 '14 at 11:46
So does your web.config file contain a connection string called `shopingConnectionString1`? — Martin Smith, Feb 06 '14 at 11:52
@EmanueleGreco - The point of supplying a canonical question answer pair is because StackOverflow is not about supplying highly localised personalised debugging sessions of no value to future visitors. — Martin Smith, Feb 06 '14 at 11:57
so type in line 25 (before line 26) this code ConfigurationManager.ConnectionStrings["shopingConnectionString1"] and debug it. Is this null or not? — Emanuele Greco, Feb 06 '14 at 14:42
then in Immediate window get ConfigurationManager.ConnectionStrings["shopingConnectionString1"].ConnectionString and post it here — Emanuele Greco, Feb 06 '14 at 14:48

Object reference not set to an instance of an object in VS 2010

0 Answers0