Executenonquery() returns -1

To add some details, if you're using a stored procedure then setting the NOCOUNT option on causes this effect. However, it does not explain why no data is found so as pointed out you either add no data or it is rolled back.

Also note that the rollback is not necessarily done on the server side


To test different variations for stored procedure behaviour consider the following scenario

Test table

CREATE TABLE NoCountTable (
   col1 int
);
GO

Test procedures

CREATE PROCEDURE NoCountProcedure AS 
BEGIN
  SET NOCOUNT ON;
  INSERT INTO NoCountTable VALUES (1);
END;
GO

CREATE PROCEDURE CountProcedure AS 
BEGIN
  SET NOCOUNT OFF;
  INSERT INTO NoCountTable VALUES (1);
END;
GO

CREATE PROCEDURE RollbackProcedure AS 
BEGIN
  SET NOCOUNT ON;
  BEGIN TRANSACTION
     INSERT INTO NoCountTable VALUES (1);
  ROLLBACK;
END;
GO

CREATE PROCEDURE ExceptionProcedure AS 
BEGIN
  SET NOCOUNT ON;
  BEGIN TRANSACTION
     INSERT INTO NoCountTable VALUES (1/0);
  ROLLBACK;
END;
GO

Calling program

int result;

using (SqlConnection connection = new SqlConnection()) {
   connection.ConnectionString = "server=.\\<instance_name_here>;integrated security=true";
   using (SqlCommand command = new SqlCommand()) {
      command.Connection = connection;
      try {
         connection.Open();

         command.CommandText = "NoCountProcedure";
         result = command.ExecuteNonQuery();
         Debug.WriteLine(string.Format("{0} returned {1}", 
                         command.CommandText,  result));

         command.CommandText = "CountProcedure";
         result = command.ExecuteNonQuery();
         Debug.WriteLine(string.Format("{0} returned {1}", 
                         command.CommandText, result));

         command.CommandText = "RollbackProcedure";
         result = command.ExecuteNonQuery();
         Debug.WriteLine(string.Format("{0} returned {1}", 
                         command.CommandText, result));

         command.CommandText = "ExceptionProcedure";
         result = command.ExecuteNonQuery();
         Debug.WriteLine(string.Format("{0} returned {1}", 
                         command.CommandText, result));
      } catch (System.Exception exception) {
         Debug.WriteLine(string.Format("Exception occurred {0}: {1}", 
                         exception.Source, exception.Message));
      }
   }
}

The output from the program is

NoCountProcedure returned -1
CountProcedure returned 1
RollbackProcedure returned -1
Exception thrown: 'System.Data.SqlClient.SqlException' in System.Data.dll
Exception occurred .Net SqlClient Data Provider: Divide by zero error encountered.
The statement has been terminated.

But as pointed out by @Pete-OHanlon, this is merely explaining different possibilities since you haven't posted any code.

How to Find It: No Code Submitted method:

1 - create the query you think you wish to execute and see if it works when run directly in SQL (however you do this).

If that successfully inserts the record:
2 - if that works, paste it into your code so that the know working query is executed via Executenonquery(). If it doesn't work, problem is in the external parts (such as a rollback or whatever).

If that successfully inserts the record:
3 - trap (possibly a print to screen?) the query you are generating with your code and see what's wrong with it. Perhaps use it in (1), above.

You have now debugged your query. Determined if it is because the SQL is no good or the rest of your handling is no good.

If the latter, check your conditionals (maybe by commenting out!) and see where things go wrong. Or better yet, use debugger.