i am getting error as nullReferenceException

Manj N

i am getting error as Object reference not set to an instance of an object.
NullReferenceException was unhandled by user..

public partial class _Default : System.Web.UI.Page

{

SqlConnection MyConnection = new SqlConnection(ConfigurationManager.AppSettings["ConnectionString"].ToString());

SqlCommand MyCommand= new SqlCommand();

string query;

protected void Page_Load(object sender, EventArgs e)

{

}

protected void submit_Click(object sender, EventArgs e)

{

query="INSERT INTO tablem (name,password) VALUES (" + name +"," + password +")";

try

{

}

catch (NullReferenceException)

{

Console.WriteLine("error ");

}

19 Replies

Know the answer? Post it — somebody with the same question will find it here.

Iftikar Hussain13y ago
try now

private void submit_Click(object sender, EventArgs e)
{
string query = "INSERT INTO tablem (name,password) VALUES(@name,@password)";
string strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
using (SqlConnection conn = new SqlConnection(strConnString))
{
if (conn.State == ConnectionState.Closed)
conn.Open();
SqlCommand cmd = new SqlCommand(query, conn);
cmd.Parameters.AddWithValue("@name", name.Text);
cmd.Parameters.AddWithValue("@password", password.Text);
cmd.ExecuteNonQuery();
if (conn.State == ConnectionState.Open)
conn.Close();
conn.Dispose();
}
}

Regards,
Iftikar
0
Manj N13y ago
what is ConnectionState , strSelectQurry..

error.. thse are not containing in content
0
Iftikar Hussain13y ago
try like this

private void submit_Click(object sender, EventArgs e)
{
string query="INSERT INTO tablem (name,password) VALUES(@name,@password)";
string strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
using (SqlConnection conn= new SqlConnection(strConnString))
{
if (conn.State == ConnectionState.Closed)
conn.Open();
SqlCommand cmd = new SqlCommand(strSelectQurry, conn);
cmd.Parameters.AddWithValue("@name",name.Text);
cmd.Parameters.AddWithValue("@password",password.Text);
SqlDataReader dReader = cmd.ExecuteReader();
cmd.ExecuteNonquery();
if (conn.State == ConnectionState.Open)
conn.Close();
conn.Dispose();
}
}

Regards,
Iftikar
0
Manj N13y ago
what is conn, ConnectionState, strSelectQurry?
0
Iftikar Hussain13y ago
try like this and put the break points and check the value for strConnString

private void submit_Click(object sender, EventArgs e)
{
string query="INSERT INTO tablem (name,password) VALUES(@name,@password)";
string strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
using (SqlConnection MyConnection = new SqlConnection(strConnString))
{
if (conn.State == ConnectionState.Closed)
conn.Open();
SqlCommand cmd = new SqlCommand(strSelectQurry, MyConnection);
cmd.Parameters.AddWithValue("@name",name.Text);
cmd.Parameters.AddWithValue("@password",password.Text);
SqlDataReader dReader = cmd.ExecuteReader();
cmd.ExecuteNonquery();
if (conn.State == ConnectionState.Open)
conn.Close();
conn.Dispose();
}
}

Regards,
Iftikar
0
Sanjeeb Lenka13y ago
did you tried it directly writing connection string in page not in web.config.
and check it is working or not

string strcon = "Data Source= DatabaseServerName; Integrated Security=true;Initial Catalog= YourDatabaseName; uid=YourUserName; Password=yourpassword; ";
SqlConnection con = new SqlConnection(strcon);
0
Manj N13y ago
same error getting..

SqlConnection MyConnection = new SqlConnection(ConfigurationManager.connectionString["conString"].ToString());

what is d error in this line?
0
Sanjeeb Lenka13y ago
check this one:

<connectionStrings>

<add name="yourconnectinstringName" connectionString="Data Source= DatabaseServerName; Integrated Security=true;Initial Catalog= YourDatabaseName; uid=YourUserName; Password=yourpassword; " providerName="System.Data.SqlClient"/>
connectionStrings >
0
Iftikar Hussain13y ago
Please use actual your sql server details

Regards,
Iftikar
0
Manj N13y ago
web config...

0
Iftikar Hussain13y ago
can you share your web config file and the modified code?

Regards,
Iftikar
0
Manj N13y ago
i am getting same error..
0
Iftikar Hussain13y ago
declare your connection string in web.config as like below and then modify the code

connectionString="Data Source=SQLEXPRESS;Initial Catalog=MyDb;Persist Security Info=True;User ID=MyUser;Password=Mypassword"
providerName="System.Data.SqlClient" />

using (SqlConnection MyConnection = new SqlConnection(ConfigurationManager.ConnectionString["conString"].ToString()))
{

Regards,
Iftikar
0
Sanjeeb Lenka13y ago
hi,

you check your web.config that you declare the connection string or not.

like this

<connectionStrings>
<add name="ConnectionString" connectionString="Data Source=SureshDasari;Integrated Security=true;Initial Catalog=MySampleDB" providerName="System.Data.SqlClient"/>
connectionStrings >

just check that

if you got any problem share your web.config code
0
Manj N13y ago
but im getting error in

SqlConnection(ConfigurationManager.AppSettings["ConnectionString"].ToString());

as

Object reference not set to an instance of an object.
NullReferenceException was unhandled by user..
0
Sanjeeb Lenka13y ago
hi ,

you did a mistake here

query="INSERT INTO tablem (name,password) VALUES (" + name +"," + password +")";

you miss .Text in this line

after modifing

query="INSERT INTO tablem (name,password) VALUES (" + name.Text +"," + password.Text +")";

use this and check this and reply
0
Iftikar Hussain13y ago
Hi,
Try like this

private void submit_Click(object sender, EventArgs e)
{
string query="INSERT INTO tablem (name,password) VALUES(@name,@password)";
using (SqlConnection MyConnection = new SqlConnection(ConfigurationManager.AppSettings["ConnectionString"].ToString()))
{
if (conn.State == ConnectionState.Closed)
conn.Open();
SqlCommand cmd = new SqlCommand(strSelectQurry, MyConnection);
cmd.Parameters.AddWithValue("@name",name.Text);
cmd.Parameters.AddWithValue("@password",password.Text);
SqlDataReader dReader = cmd.ExecuteReader();
cmd.ExecuteNonquery();
if (conn.State == ConnectionState.Open)
conn.Close();
conn.Dispose();
}
}

Regards,
Iftikar
0

Manj N13y ago

i m taking from another aspx program..

Sign In

Sanjeeb Lenka13y ago
HI,

From where you are getting name and password for your query. you didn't mention that in code.

query="INSERT INTO tablem (name,password) VALUES (" + name +"," + password +")";
0