coversion

If you're still getting an error, then presumably it's on this line:

 userid = Int32.Parse(cmd.ExecuteScalar().ToString());

As it's a nvarchar in the database, is the userid actually numeric (e.g. 123) or alphanumeric (e.g. A123)?

If it's the latter, then you'll need need to strip away the alphabetic character(s) before you can parse what's left to an integer.

Well, the ExecuteScalar method returns an object so you'll need to apply ToString() first before you can apply int.Parse.

Also. you don't actually need the DataAdapter here as your stored procedure is (presumably) returning a single value. So I'd try:

hi, I have tried your suggestion but i don't want conversion for a particular string You see my code below...

protected void Button1_Click(object sender, EventArgs e)

    {

        int  userid = 0;

        string str = ConfigurationManager.ConnectionStrings["GalleryString"].ConnectionString;

        using (SqlConnection cn = new SqlConnection(str))

        {

            using (SqlCommand cmd = new SqlCommand("AddCustomer"))

            {

                using (SqlDataAdapter da = new SqlDataAdapter())

                {

                    cmd.CommandType = CommandType.StoredProcedure;

                    cmd.Parameters.AddWithValue("@FName", txtFName.Text);

                    cmd.Parameters.AddWithValue("@MName", txtMName.Text);

                    cmd.Parameters.AddWithValue("@LName", txtLName.Text);

                    cmd.Parameters.AddWithValue("@DOB", txtDOB.Text);

                    cmd.Parameters.AddWithValue("@MobileNo", txtMob.Text);

                    cmd.Parameters.AddWithValue("@Emailid", emailtxt.Text);

                    cmd.Parameters.AddWithValue("@gender", txtGender.Text);

                    cmd.Parameters.AddWithValue("@password", txtPswrd.Text);

                    cmd.Parameters.AddWithValue("@cnfswrd", txtVerify.Text);

                    cmd.Connection = cn;

                    cn.Open();

                   

                  

                    userid = Int32.Parse(cmd.ExecuteScalar());//I want the conversion here

                        cn.Close();

 

                }

            }

            string msg = string.Empty;

            switch (userid)

            {

                case -1: msg = "username exists";

                    break;

                case -2: msg = "emailid has been used" + userid.ToString();

                    break;

                default:

                    msg = "registration successfull" + userid.ToString();

                    break;

            }

            ClientScript.RegisterStartupScript(GetType(), "alert", "alert('" + msg + "');", true);

        }

 

    }

}

Hello Anjali,
You can try the below format. But please if possible convert the userID type in the table to int, as the mismatch is against consistency. But still for the time being try with:-

int userID = Int32.Parse("THE STRING ID");
Please try this. 
Accept if works.
Else post back your queries.
Thanks