Sqldatareader 'invalid attempt to read when no data is present'

Question

0.00/5 (No votes)

See more:

I am using Visual Studio 2015 Enterprise edition for asp.net project in which i am getting error "

Invalid attempt to read when no data is present

"

Actually the SqlDataReader is executing the command but i am getting this error can anyone explain me where is the wrong

What I have tried:

con = new SqlConnection(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString);
if (con.State == ConnectionState.Closed)
    con.Open();
string str = "select RoleName from tblRoles";

cmd = new SqlCommand(str, con);
sdr = cmd.ExecuteReader();

string roleName = sdr["RoleName"].ToString();

I am getting error at the last line saying 'Invalid attempt to read when no data is present'

Posted 4-Mar-18 20:14pm

Member 8583441

Updated 4-Mar-18 20:36pm

Add a Solution

Comments

Member 8583441 5-Mar-18 2:17am

I've tried string roleName = sdr.GetValue(1).ToString(); but no use

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 · Accepted Answer · 2018-03-04T20:37:00

To use a DataReader, you have to tell it to read each line at a time:

C#

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT RoleName FROM tblRoles", con))
        {
        using (SqlDataReader reader = cmd.ExecuteReader())
            {
            while (reader.Read())
                {
                string roleName = (string) reader["RoleName"];
                Console.WriteLine(roleName);
                }
            }
        }
    }