ASP.NET Object reference not set to an instance of an object

Question

I have no problem in local. But I get this error in uploaded website:

Object reference not set to an instance of an object.

In this link it says this is a bug with ADO but I dont use ADO in my code.

Here is my code:

        SqlConnection sc = new SqlConnection();
        sc.ConnectionString = MyConnectionString;
        sc.Open();
        SqlCommand scm = new SqlCommand(INSERT COMMAND);
        scm.Connection = sc;
        scm.ExecuteNonQuery();
        sc.Close();

I put my above code in USING statements and nothing changed.

Here is my stack trace

NullReferenceException: Object reference not set to an instance of an object.]
Register.BtnRegister_Click(Object sender, ImageClickEventArgs e) +601
System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +115
System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +120

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) +36
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5563

And here is BtnRegister_Click code:

    protected void BtnRegister_Click(object sender, ImageClickEventArgs e)
    {
    if (TxtName.Text == "" || TxtFamily.Text == "" || txtNationalCode.Text == "" || TxtIdNumber.Text == "" || txtMobile.Text == "" || TxtEmail.Text == "" || txtAddress.Text == "" || TxtSecurityCode.Text == "")
    {
        LblMsg.Text = "You should fill all fields";
        return;
    }

    if (txtNationalCode.Text.Length != 10)
    {
        LblMsg.Text = "National code must have 10 digits";
        return;
    }

    if (txtMobile.Text.Length != 11)
    {
        LblMsg.Text = "Mobile number should have 11 digits";
        return;
    }

    if (T_Paticipant.GetDataByNationalCode(txtNationalCode.Text).Rows.Count > 0)
    {
        LblMsg.Text = "This national code used before";
        return;
    }

    if (T_Paticipant.GetDataByEmail(TxtEmail.Text).Rows.Count > 0)
    {
        LblMsg.Text = "This email used before";
        return;
    }

    LblMessage.Text = "Are you sure to register?";
    LblFlag.Text = "0";


    //captcha

    if (this.Session["CaptchaImageText"].ToString().ToLower() == TxtSecurityCode.Text.ToLower())
    {
        Page.ClientScript.RegisterStartupScript(this.GetType(), "showMessage()", "<script>ShowMessage() </script>");
    }
    else
    {
        LblMsg.ForeColor = System.Drawing.Color.Red;
        LblMsg.Text = "Security code is wrong";
    }
    //end captcha
}

Thank you for help.

Aside from anything else, you should be using using statements to close your commands and connections. — Jon Skeet
– Jon Skeet, Commented Oct 13, 2012 at 8:07
@NickW: I dont know how to debug it line by line, because its not local, I uploaded it. — Masoud Keshavarz
– Masoud Keshavarz, Commented Oct 13, 2012 at 8:13
Now you don't assign the Connection to the Command and you should show what INSERT COMMAND is. — Tim Schmelter
– Tim Schmelter, Commented Oct 13, 2012 at 8:14

Lion · Accepted Answer · 2012-10-13 08:51:44Z

2

set the connectionstring first before opening

    SqlConnection sc = new SqlConnection();
    sc.ConnectionString = MyConnectionString
    SqlCommand scm = new SqlCommand(INSERT COMMAND);
    scm.Connection = sc;           // missing this.
    sc.Open();
    scm.ExecuteNonQuery();
    sc.Close();

or

using (SqlConnection conn = new SqlConnection("connectionstringhere"))
{
    using (SqlCommand comm = new SqlCommand())
    {
        comm.Connection = conn;
        comm.CommandText = "your query";
        comm.CommandType = CommandType.Text;
        // comm.Parameters.AddWithValue("@paramName","value"); // if you have parameters
        try
        {
            conn.Open();
            comm.ExecuteNonQuery();
        }
        catch(SqlException ex)
        {
            // error here
            // ex.Message.Tostring  // holds the error message
        }
    }
}

edited Oct 13, 2012 at 8:51

Lion

19.1k22 gold badges83 silver badges111 bronze badges

answered Oct 13, 2012 at 8:07

John Woo

265k70 gold badges509 silver badges500 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Masoud Keshavarz Over a year ago

I am sorry, But it was correct in my code. In here I writed it wrong

John Woo Over a year ago

@masoudkeshavarz check my updated answer. set connection to your command.

Jon Skeet Over a year ago

@masoudkeshavarz: You must make sure you post your actual code in future. There's no point in us finding bugs in irrelevant code. It's worth taking an extra few minutes to make sure your question is as good as it can be before posting. Please read tinyurl.com/so-hints

Masoud Keshavarz Over a year ago

yes im really sorry. next time I post question after I was sure. Im sorry again.

Masoud Keshavarz Over a year ago

I used using statement just like you said and nothing changed. Also I dont have any error in local. I updated my question. Thank you for help.

iefpw · Accepted Answer · 2012-10-13 08:12:55Z

0

It should be new SqlCommand(query, sc)

answered Oct 13, 2012 at 8:12

iefpw

7,08215 gold badges59 silver badges83 bronze badges

Comments

Masoud Keshavarz · Accepted Answer · 2012-10-13 16:54:04Z

0

Thank you everyone for help. This error occurred because value of a session was null and ToString() method couldn't find any data to convert.

answered Oct 13, 2012 at 16:54

Masoud Keshavarz

2,2449 gold badges40 silver badges49 bronze badges

Collectives™ on Stack Overflow

ASP.NET Object reference not set to an instance of an object

3 Answers 3

5 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

5 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related