CODEWITHSUNDEEP
asp.netvisual-studio
user2514307
user2514307

Reputation: 59

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

I'm not really good at programming and I don't know what's happening in my codes, it works well before but now I get this error:

NullReferenceException was unhadled by user code.

Object Reference not set to an instance of an object.

Here's my code:

 void GetProfileInfo()
    {
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = "SELECT FirstName, LastName, Address, ContactNo, EmailAddress FROM Users " +
            "WHERE UserID=@UserID";
        cmd.Parameters.Add("@UserID", SqlDbType.Int).Value = Session["userid"].ToString();
        SqlDataReader data = cmd.ExecuteReader();
        while (data.Read())
        {
            txtFN.Text = data["FirstName"].ToString();
            txtLN.Text = data["LastName"].ToString();
            txtAddress.Text = data["Address"].ToString();
            txtContact.Text = data["ContactNo"].ToString();
            txtEmail.Text = data["EmailAddress"].ToString();
        }
        con.Close();
    }

Upvotes: 0

Views: 228

Answers (1)

Nick
Nick

Reputation: 4212

First you have to check all occurrences where Session["userid"] is initialized, then in order to avoid exception error you have to check this variable value whether is null or wrap the code with try catch finally blocks

Ex: 

try
{
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = "SELECT FirstName, LastName, Address, ContactNo, EmailAddress FROM Users " +
            "WHERE UserID=@UserID";
        cmd.Parameters.Add("@UserID", SqlDbType.Int).Value = Session["userid"].ToString();
        SqlDataReader data = cmd.ExecuteReader();
        while (data.Read())
        {
            txtFN.Text = data["FirstName"].ToString();
            txtLN.Text = data["LastName"].ToString();
            txtAddress.Text = data["Address"].ToString();
            txtContact.Text = data["ContactNo"].ToString();
            txtEmail.Text = data["EmailAddress"].ToString();
        }
}
catch(Exception e)
{
    string message = e.Message;
    MessageBox.Show(message);
}
finally
{
        con.Close();
}

Upvotes: 1

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