How to get error message when retriving data from db, but no values there

Question

I am having one table say emp, in that i dont have any values. If i using this query "select * from emp" in the asp.net coding like below:

con.Open();
String str="select * from emp where empname='Abdul'";

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

while(dr.Read())
{
  textBox1.text=dr[0].ToString();
  textBox2.text=dr[0].ToString();
  textBox3.text=dr[0].ToString();
}

con.Close();

In emp tables, i dont have any empname as abdul, When i am doing this it should show some errors, how to do it?

Answer 1

Do something like this:

if (dr == null || !dr.HasRows) 
{
//NO record found
   lblError.Text ="No Records Found!";
}
else
{
//Record Found SUCCESS!
while(dr.Read())
{
  textBox1.text=dr[0].ToString();
  textBox2.text=dr[0].ToString();
  textBox3.text=dr[0].ToString();
}

}

Regards

Answer 2

No it does not show any error because you enter the while only if there are some results in the query.

I would use an if/else and if DataReader has no content because no results found, I would notify the user or show something in the UI, depends on the type of application and on your exact needs.

Answer 3

You could load your data from a SQLDataAdapter in to a DataSet and use the following:

if (DataSet.Tables[0].Rows.Count <=0)
{

}