Exception problem

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Exception problem

Peter_1985 2,736

Hi,

I've got issue

User's image

due to this line below.

reader = cmd.ExecuteReader();

Can it be owing to no record returned?

KOZ6.0 6,655 Reputation points

2024-05-10T10:52:13.8933333+00:00

It cannot be determined without the preceding and following codes.

Please provide at least an error message.
Olaf Helper 47,436 Reputation points

2024-05-10T11:00:47.1966667+00:00

Can it be owing to no record returned?

No, definetively not, you would get an "empty" reader.

But I can't say more, because you didn't provide any usefull informations like more code and a screenshot of a part of an error message isn't helpfull; post it as text.
Anonymous

2024-05-16T03:33:51.0466667+00:00
Hi @Peter_1985 , Welcome to Microsoft Q&A,

you should check if there are any records before trying to read them. Here's an example of how you can do this:

using (var reader = cmd.ExecuteReader()) { if (reader.HasRows) { // Read the records here } else { // Handle the case when no records are returned } }

By using reader.HasRows, you can check if there are any records to be read before trying to read them. This will prevent errors when trying to read from an empty result set.

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KOZ6.0 6,655 Reputation points

2024-05-10T10:52:13.8933333+00:00

It cannot be determined without the preceding and following codes.

Please provide at least an error message.
Olaf Helper 47,436 Reputation points

2024-05-10T11:00:47.1966667+00:00

Can it be owing to no record returned?

No, definetively not, you would get an "empty" reader.

But I can't say more, because you didn't provide any usefull informations like more code and a screenshot of a part of an error message isn't helpfull; post it as text.
Anonymous

2024-05-16T03:33:51.0466667+00:00

Hi @Peter_1985 , Welcome to Microsoft Q&A,

you should check if there are any records before trying to read them. Here's an example of how you can do this:

using (var reader = cmd.ExecuteReader()) { if (reader.HasRows) { // Read the records here } else { // Handle the case when no records are returned } }

By using reader.HasRows, you can check if there are any records to be read before trying to read them. This will prevent errors when trying to read from an empty result set.

Answer 1

Can it be owing to no record returned?

The other way round. No rows are being returned, because your query/batch run into an error.

You need to capture the error message with an exception handler and get the text of the error message.

Here is a simple sample program of how to capture exceptions with SqlDataReader_

using System.Data.SqlClient;

public static class SqlErrorRepro {
   private static string sqlBatchText = @"
      BEGIN TRY
         SELECT name, log(max_length) FROM sys.columns
      END TRY
      BEGIN CATCH
          ; THROW
      END CATCH";

   private static string connString =
        @"Data Source=.;Integrated Security=SSPI;Database=tempdb";

   public static void Main() {
      try {
         using (SqlConnection cn = new SqlConnection(connString))
         using (SqlCommand cmd = new SqlCommand(sqlBatchText, cn)) {
            int rowCount = 0;
            cn.Open();
            using (SqlDataReader reader = cmd.ExecuteReader()) {
               while(reader.Read()) { ++rowCount; };
               while(reader.NextResult());
            }
            System.Console.WriteLine("{0} rows read", rowCount);
         }
      }
      catch (System.Exception ex){
         System.Console.WriteLine("ERROR: " + ex.Message);
      }
   }
}

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Exception problem

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