Object reference not set to an instance of Object

Question

User-797751191 posted

Hi

   When no record if found i get above error . I want that if no record found then message should get displayed 'No record found'.

In Status it shows Null

                using (SqlCommand cmd = new SqlCommand("SELECT Status FROM test3 Where [No]=@INo", con))
                {
                    cmd.CommandType = CommandType.Text;
                    cmd.Parameters.AddWithValue("@INo", txtNo.Text.Trim());
                    Status = cmd.ExecuteScalar().ToString();

Thanks

Answer 1

User-158764254 posted

give this a read:

https://stackoverflow.com/questions/16647140/return-value-using-string-result-command-executescalar-error-occurs-when-resul

Answer 2

User475983607 posted

Hi

   When no record if found i get above error . I want that if no record found then message should get displayed 'No record found'.

In Status it shows Null

                using (SqlCommand cmd = new SqlCommand("SELECT Status FROM test3 Where [No]=@INo", con))
                {
                    cmd.CommandType = CommandType.Text;
                    cmd.Parameters.AddWithValue("@INo", txtNo.Text.Trim());
                    Status = cmd.ExecuteScalar().ToString();

Thanks

ExecuteScalar returns and object as illustrated in the docs.  If your SQL design can return NULL then you need to check for NULL before using .ToString().

object result = cmd.ExecuteScalar();
if(result == null) 
{
   // No record found
}

ExecuteScalar() reference docs.

https://docs.microsoft.com/en-us/dotnet/api/system.data.sqlclient.sqlcommand.executescalar?view=netframework-4.8

Answer 3

User1120430333 posted

Well, you can do a null value check.

If (Status == null)
{
  //do one thing
}
else
{
  //do something else if not null
}

Answer 4

User1120430333 posted

You made the same post in two ASP.NET forums. The moderators kind of don't like that.