when to use reader.read() and when to not RSS

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  shan000

  Member

  491 Points

  446 Posts

  when to use reader.read() and when to not

  May 09, 2012 05:52 AM|LINK

  Hi ,

  im using reader.read() in many times in reading data from database from my web application.

  some where i get error as  ""Invalid attempt to read when no data is present""

  but this error is removed when i use rdr.read() after executing reader in command.

  why i get his error. is it better to call reader.read() function as some where im getting data iwthout using rdr.read() function just by rdr=cmd.executereadeR() function.

  
  

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  karthicks

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  5422 Posts

  Re: when to use reader.read() and when to not

  May 09, 2012 06:08 AM|LINK

  hi, here is perfect example , before calling dataReader.Read() check using if (dataReader.HasRows)

  generally you will get this error when you try read data from datareader before calling dataReader.Read()

  SqlConnection connection = new SqlConnection("server=2.1.6.8;Initial Catalog=data;Integrated Security=true;");
  		SqlCommand command = new SqlCommand("select top 5 * from Countries", connection);
  		connection.Open();
  		SqlDataReader dataReader = command.ExecuteReader();
  		if (dataReader.HasRows)  {
  			while (dataReader.Read())  {
  				//your code
  			}
  		}
  		connection.Close();

  Refer :http://www.dotnetperls.com/sqldatareader

  http://www.csharp-station.com/Tutorial/AdoDotNet/lesson04

  Thanks,
  Karthick S
  • Marked as answer by shan000 on May 09, 2012 05:54 PM
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  amit.jain

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  Re: when to use reader.read() and when to not

  May 09, 2012 06:13 AM|LINK

  refer http://csharpdotnetfreak.blogspot.com/2012/05/executereader-example-in-aspnet-c-vbnet.html

  http://csharpdotnetfreak.blogspot.com/2012/05/executenonquery-executescalar-reader.html

  Don't say thanks rather mark my reply as "Answer" if it helps you
  amiT jaiN
  
  ASP.NET C# VB Articles And Code Examples
  • Edited by amit.jain on Jun 19, 2012 12:48 PM