Exception:There is no row at position 0.

I think this will help you..... I'm giving you this code as per your code....

private void Button_click(object sender, EventArgs e)
{
  Button _sender = (Button)sender;
  _sender.Enabled = false;
  DataSet ds = new DataSet();
  SqlDataAdapter da = new SqlDataAdapter("select Loginname,password from pegtables.tblusers where  userid=1", ConfigurationManager.AppSettings["CS_localsource"]);
  
  try{
  da.Fill(ds,"emp");
  }
  catch(Exception ex)
  { throw new Exception(ex.Message);}         
  DataTable dt = ds.Tables[0];
  if(dt.Rows.Count>0)
  {
    DataRow dr = dt.Rows[0];
    textBox1.Text = Convert.ToString(dr[0]);
    textBox2.Text = Convert.ToString(dr[1]);
  }
  else
  {
     //code to give message about no user found with this username and password...
  }
  _sender.Enabled = true;
}

In answer to your comment to my original answer, here is how I would do a simple User access class :

class User
        {
            public string UserName { get; set; }
            public string Password { get; set; }

            private static User GetUser(int userID)
            {
                using (SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["CS_localsource"]))
                {
                    SqlCommand cmd = new SqlCommand("select Loginname, password from pegtables.tblusers where userid=@UserID", con);
                    cmd.Parameters.AddWithValue("@UserID", userID);
                    con.Open();
                    SqlDataReader dr = cmd.ExecuteReader();
                    User currentUser = new User();
                    if (dr.HasRows)
                    {
                        while (dr.Read())
                        {
                            currentUser.UserName = dr.IsDBNull(0) ? "Unknown User" : dr.GetString(0);
                            currentUser.Password = dr.IsDBNull(1) ? "UnknownPassword" : dr.GetString(1);
                        }
                        return currentUser;
                    }
                    else
                    {
                        throw new Exception("User not found");
                    }
                }

            }
        }

I way prefer to use a DataReader to get my info from the data source than using DataSets and such like.

Hope this helps

DataSet ds = new DataSet();
  SqlDataAdapter da = new SqlDataAdapter("select Loginname,password from pegtables.tblusers where userid=1", ConfigurationManager.AppSettings["CS_localsource"]);
  da.Fill(ds,"emp");
               
  DataTable dt = new DataTable(ds.Tables[0].TableName.ToString());
  
if(dt.Rows.Count>0)
{
  textBox1.Text = dr[0][0].ToString();
  textBox2.Text = dr[0][1].ToString();
}

<pre>
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter("select Loginname,password from pegtables.tblusers where userid=1", ConfigurationManager.AppSettings["CS_localsource"]);
da.Fill(ds);

DataTable dt = new DataTable();
dt=ds.Tables[0];
if(dt.Rows.Count>0)
{
textBox1.Text = dr[0][0].ToString();
textBox2.Text = dr[0][1].ToString();
}
</pre>

I think the problem lies here

DataTable dt = new DataTable(ds.Tables[0].TableName.ToString());
  DataRow dr = dt.Rows[0];

although you initiate a new DataTable, it does not yet have any rows. I am not sure what you are trying to achieve overall, but I think you might be looking to do something like this

DataTable dt = ds.Tables[0];

which would make dt equal to the first table in the DataSet.

Hope this helps

This is a normal error that occurs when you are trying to access a row that is not there.The Perfect solution to avoid this error is to check whether that row does exist there,i.e in your case you are trying to access the first and second rows of datatable dt,so to avoid error in code try this :



<code>
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter("select Loginname,password from pegtables.tblusers where userid=1", ConfigurationManager.AppSettings["CS_localsource"]);
da.Fill(ds,"emp");

DataTable dt = new DataTable(ds.Tables[0].TableName.ToString());
if(dt.Rows.Count&amp;gt;0)
{
DataRow dr = dt.Rows[0];
textBox1.Text = dr[0].ToString();
textBox2.Text = dr[1].ToString();
}
</code>

The problem is because the datatable is blank or query return blank result. just check the Rowcount before asignment. and then put it inside try{} catch{} block.

This can be solve by below given steps

Dataset dSet = new Dataset();
if(dSet.Tables.Count>0) // if Yes
{
if(dSet.Tables[0].Rows.Count> 0)
{
//Your logic
}
}