Error: Object reference not set to an instance of the object

Question

0.00/5 (No votes)

See more:

Code:

C#

public string Login_Handler(string Username, string password, out string Details)
   {
       Database dblogin = null;
       DbConnection dbconn = null;
       DbCommand lgncmd;
       string Sp_login = string.Empty;
       string Str_Details = string.Empty;
       try
       {
           if (dbconn.State == ConnectionState.Closed)
           {
               dblogin = DatabaseFactory.CreateDatabase();
               dbconn = dblogin.CreateConnection();
               dbconn.Open();
           }

           lgncmd = dbconn.CreateCommand();
           Sp_login = "exec usp_login";
           lgncmd.CommandType = CommandType.StoredProcedure;
           lgncmd = dblogin.GetStoredProcCommand(Sp_login);

           Username = (string.IsNullOrEmpty(Username) ? string.Empty : Username.Trim());
           password = (string.IsNullOrEmpty(password) ? string.Empty : password.Trim());

           dblogin.AddInParameter(lgncmd, "@uname", DbType.String, Username.Trim());
           dblogin.AddInParameter(lgncmd, "@pass", DbType.String, password.Trim());

           dblogin.AddOutParameter(lgncmd, "@id", DbType.Int16, 10);

           dblogin.ExecuteNonQuery(lgncmd);

           Details = Convert.ToString(lgncmd.Parameters["@id"].Value);
       }
       catch (Exception ex)
       {

           throw ex;
       }
       finally
       {
           if (dbconn.State == ConnectionState.Open)
           {
               dbconn.Close();
               dbconn.Dispose();
               dblogin = null;
           }
       }
       return Str_Details;
   }

Error:
object reference not set to an instance of an object

error in the line DbConnection and Database. I also used the proper dll for those commands but still it is showing error.

Posted 7-Feb-14 1:17am

riodejenris14

Updated 7-Feb-14 1:22am

v2

Add a Solution

Comments

Ajay_Babu 7-Feb-14 7:18am

which line it shows error?

riodejenris14 7-Feb-14 7:20am

In the if condition Mr.Ajay, and it is moving to catch block with the message object reference not set to an instance of an object

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2014-02-07T01:24:00

If you are "always getting struck" by the same error, then it's probably time you stopped doing that...
Look at your code:

C#

Database dblogin = null;
DbConnection dbconn = null;
DbCommand lgncmd;
string Sp_login = string.Empty;
string Str_Details = string.Empty;
try
{
    if (dbconn.State == ConnectionState.Closed)

You create a variable to reference a DbConnection (dbconn), and you set it to null.
The next time you use it, you try to access a property. So the system looks at it, and sees it is null - i.e. has no instance - and rightly throws an exception.

You need to create an instance of your DbConnection class, and assign it to dbconn before you can use it. Probably, along the lines of this:

C#

DbConnection dbconn = new DbConnection();

If you think of cars instead of variables, a parking space is a place to store an instance of a car: but you can't drive away while the space is empty, because it doesn't have a car in it to drive! You have to go to a parking space that contains a car (preferably yours) before you can drive off.