Hello!  We're seeing some very odd results from the below code.  Under
certain conditions, ADO.NET will create commands that specify a
negative zero amount ("-0.00").  It's easy to reproduce.

This is a major issue in our application as we do lots of decimal math
and rely on SqlDataAdapter and SqlCommandBuilder to do our data
updates.  As a result, we have intermittent failure.  We compare the
supposedly "zero" value to 0 inside of a trigger.  When the value
reaches SQL Server as a "negative zero", some actions are undefined.

This is a potentially serious framework bug.  I'd like to see it
verified by someone at Microsoft.  Ideas for a workaround are welcome.
If no workaround, a T-Shirt or something would be nice!  :)

Thanks,
Jon

=========================

// Run in Visual Studio 2005 "Console Mode"
using System;
using System.Data;
using System.Data.SqlClient;

namespace BadZero {
  class Program {
     static bool IsDecimalZero(decimal input) {
        SqlConnection Connection = new SqlConnection(
           @"Data Source=localhost;Trusted_Connection=True");
        Connection.Open();
        // Send command to SQL to check the value against zero
        SqlCommand Command = new SqlCommand(
           "IF @p1 = 0 SELECT 'Equal' ELSE SELECT 'Not Equal'",
           Connection);
        SqlParameter Param = new SqlParameter("@p1",
           SqlDbType.Decimal);
        Param.Value = input;
        Command.Parameters.Add(Param);
        string Result = Command.ExecuteScalar() as string;
        // When BadZero is passed in, using SQL Profiler, we see
        // @p1 being set to:
        //    GoodZero: 0.00
        //    BadZero:  -0.00   (yes, MINUS 0.00)
        Connection.Close();
        return Result == "Equal";
     }

     static void Main(string[] args) {
        decimal GoodZero = 0.00m;
        decimal BadZero  = 0.00m - 0;
        // Look the same, but different internally
        Console.WriteLine("GoodZero:{0}   BadZero:{1}",
           decimal.GetBits(GoodZero)[3], decimal.GetBits(BadZero)[3]);

        bool GoodResult = IsDecimalZero(GoodZero);    // true
        bool BadResult  = IsDecimalZero(BadZero);     // false

        Console.WriteLine("GoodResult:{0}   BadResult:{1}",
           GoodResult.ToString(), BadResult.ToString());
     }
  }
}