SqlCommand sqlCommand = new System.Data.SqlClient.SqlCommand("my stored procedure", new SqlConnection("my connection string"));
sqlCommand.CommandType = CommandType.StoredProcedure;
			
//параметры входные
sqlCommand.Parameters.Add("@InputParam1", SqlDbType.Int).Value = intVar;
sqlCommand.Parameters.Add("@InputParam2", SqlDbType.VarChar,  256 ).Value = strVar;

//параметры выходные
System.Data.SqlClient.SqlParameter pOut;
pOut = sqlCommand.Parameters.Add("@OutputParam1", SqlDbType.Int);
pOut.Direction = ParameterDirection.Output;
pOut = sqlCommand.Parameters.Add("@OutputParam2", SqlDbType.VarChar,  256 );
pOut.Direction = ParameterDirection.Output;
			
sqlConnection.Open();
			
try
{
	sqlCommand.ExecuteScalar();
}
finally 
{
	sqlConnection.Close();
}

int intResult;
string strResult;

try
{
	intResult = Convert.ToInt32(sqlCommand.Parameters["@OutputParam1"].Value);
	strResult = Convert.ToString(sqlCommand.Parameters["@OutputParam2"].Value);
}
catch
{
	intResult =  0 ;
	strResult = "";
}

 kxmep 

SqlConnection sqlConnection = new SqlConnection("my connection string");
			SqlCommand sqlCommand = new System.Data.SqlClient.SqlCommand("my stored procedure", sqlConnection);

 kxmep