
Posted: December 20, 2013
.Net DataReader Wrapper
UPDATE 2.0!!!
Wow, just realized it’s been awhile since i posted anything… well kiddies, time for some new code.
Although I have grown up loveing, carressing, and mutilating Visual Basic, I have decided to take a stab at some C# since most of my projects lately have comes across in the form of PHP. Â While I do love VB still, I am starting to fall hard for some C# sexyness (<- spelling).
I have a VB version of what I am about to post as well, and though the language structure is different, there really aren’t very many differences between the 2. Â I thought I may get some sort of performance boost out of this “conversion” but alas, I was mistaken. Â Both languages performed admirably clocking in at 1.19secs each to pull in 87,000 records from a pretty complicated query.
I have added in some .Net 4.5 niceties to the C# version, that I will port over to VB, but for now let’s let that sleeping beast lie in wait and get to the goodies!
Here is the code kiddies… have fun and do what you will with it.  Just do me a favor… if you make it better, let me know what you did, and where i went wrong please?!?  I’ll leave it up to you to figure out how to use it properly, but I’ll also post my test code first 😉
Test: program.cs
using o7th.Class.Library.Data; using System; using System.Collections.Generic; using System.Threading; using System.Threading.Tasks; using System.Linq; namespace Testing { class Program { static void Main(string[] args) { long startTime = DateTime.Now.Ticks; IList<Typing> _T = default(IList<Typing>); _T = Wrapper.GetResults<Typing>("List.ZipSearch", System.Data.CommandType.StoredProcedure, new string[] {"@ZipCode", "@RadiusMile"}, new object[]{"01020", 100}, new System.Data.SqlDbType[]{System.Data.SqlDbType.VarChar, System.Data.SqlDbType.Float}); long endTime = DateTime.Now.Ticks; TimeSpan timeTaken = new TimeSpan(endTime - startTime); Console.WriteLine("Task Took: " + timeTaken + " for: " + _T.Count + " records."); Thread.Sleep(2000); long startTime2 = DateTime.Now.Ticks; IList<Typing> _T2 = default(IList<Typing>); _T2 = WrapperAsync.GetResults<Typing>("List.ZipSearch", System.Data.CommandType.StoredProcedure, new string[] { "@ZipCode", "@RadiusMile" }, new object[] { "01020", 100 }, new System.Data.SqlDbType[] { System.Data.SqlDbType.VarChar, System.Data.SqlDbType.Float }); long endTime2 = DateTime.Now.Ticks; TimeSpan timeTaken2 = new TimeSpan(endTime2 - startTime2); Console.WriteLine("Task Took: " + timeTaken2 + " for: " + _T2.Count() + " records."); Console.WriteLine(""); Console.WriteLine("Press any key to continue..."); Console.ReadKey(); } partial class Typing { public long ZipID { get; set; } } } }
Access.cs
using System; using System.Data; using System.Data.Common; using System.Data.SqlClient; using System.Threading.Tasks; namespace o7th.Class.Library.Data { internal class Access : IDisposable { #region "Properties" // Set the type of query we are running private CommandType _QT; internal CommandType QueryType { set { _QT = value; } } // Set the actual query text to run private string _Qry; internal string Query { set { _Qry = value; } } // Set the parameter names if there are any private string[] _PNs; internal string[] ParameterNames { set { _PNs = value; } } // Set the parameter values if there are any private object[] _PVs; internal object[] ParameterValues { set { _PVs = value; } } // Set the actual Sql Data Types if there are any private System.Data.SqlDbType[] _DTs; internal System.Data.SqlDbType[] ParameterDataTypes { set { _DTs = value; } } // Check to see if there are any parameters passed private bool AreParams() { // Check to see if the values and names are null first if (_PVs != null && _PNs != null) { try { Type _t_pv = _PVs.GetType(); Type _t_pn = _PNs.GetType(); if (_t_pv.IsArray && _t_pn.IsArray) { return (_PVs.Length > 0 && _PNs.Length > 0) ? true : false; } else { return false; } } catch { // yes I meant to do this, we really don't need to get the exception here return false; } } else { return false; } } // Get a return message if any private string _Msg; internal string Message { get { return _Msg; } } // Get the connection string from our class assemblies settings internal string _ConnString { get { return Properties.Settings.Default.ConnectionString; } } // Set the official Sql Reader object private SqlDataReader _Rdr; // Set the official Sql Connection object private SqlConnection _Conn; // Set the official Sql Command object private SqlCommand _Cmd; // Hack for seeing if we're disposed already private bool disposedValue; #endregion // Constructor internal Access() { Invoke(); } // Official Constructor. We can thread these 2 becuase they are not being used yet, and it makes it slightly more efficient internal void Invoke() { try { Parallel.Invoke(() => { _Conn = new SqlConnection(_ConnString); }, () => { _Cmd = new SqlCommand(); }); }catch (Exception ex) { _Msg = "Access.Invoke Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.Invoke", _Msg); } } /// <summary> /// Return a SqlDataReader based on the properties passed to this class /// </summary> /// <returns></returns> internal SqlDataReader GetResults() { try { // check for parameters if (AreParams()) { PrepareParams(_Cmd); } // set our connection _Cmd.Connection = _Conn; // set the type of query to run _Cmd.CommandType = _QT; // set the actual query to run _Cmd.CommandText = _Qry; // open the connection _Cmd.Connection.Open(); // prepare the command with any parameters that may have gotten added _Cmd.Prepare(); // Execute the SqlDataReader, and set the connection to close once returned _Rdr = _Cmd.ExecuteReader(CommandBehavior.CloseConnection); // clear out any parameters _Cmd.Parameters.Clear(); // return our reader object return (!_Rdr.HasRows) ? null: _Rdr; } catch (SqlException SqlEx) { _Msg += "Acccess.GetResults SqlException: " + SqlEx.Message; ErrorReporting.WriteEm.WriteItem(SqlEx, "o7th.Class.Library.Data.Access.GetResults", _Msg); return null; } catch (Exception ex) { _Msg += "Acccess.GetResults Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.GetResults", _Msg); return null; } } /// <summary> /// Execute a non-return query, and return the success /// </summary> /// <returns></returns> internal bool Execute() { try { // check for parameters if (AreParams()) { PrepareParams(_Cmd); } // set our connection _Cmd.Connection = _Conn; // set the type of query to run _Cmd.CommandType = _QT; // set the actual query to run _Cmd.CommandText = _Qry; // open the connection _Cmd.Connection.Open(); // prepare the command with any parameters that may have gotten added _Cmd.Prepare(); // execute the non-returnable query against the database _Cmd.ExecuteNonQuery(); // clear out any parameters _Cmd.Parameters.Clear(); // executed successfully (otherwise would have thrown an exception) return true; } catch (SqlException SqlEx) { _Msg += "Access.Execute SqlException: " + SqlEx.Message; ErrorReporting.WriteEm.WriteItem(SqlEx, "o7th.Class.Library.Data.Access.Execute", _Msg); return false; } catch (Exception ex) { _Msg += "Access.Execute Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.Execute", _Msg); return false; } } /// <summary> /// Execute a query with a return value. Used in Selecting the ID of the last inserted record. /// </summary> /// <typeparam name="T"></typeparam> /// <param name="_DefVal"></param> /// <returns></returns> internal T ExecuteWithReturn<T>(T _DefVal) { try { T _Ret; // check for parameters if (AreParams()) { PrepareParams(_Cmd); } // set our connection _Cmd.Connection = _Conn; // set the type of query to run _Cmd.CommandType = _QT; // set the actual query to run _Cmd.CommandText = _Qry; // open the connection _Cmd.Connection.Open(); // prepare the command with any parameters that may have gotten added _Cmd.Prepare(); T _T = (T)_Cmd.ExecuteScalar(); _Ret = (_T is DBNull) ? default(T) : _T; // clear out _T _T = default(T); // clear out any parameters _Cmd.Parameters.Clear(); // return the single return value from the query run return _Ret; } catch (SqlException SqlEx) { _Msg += "Access.ExecuteWithReturn SqlException: " + SqlEx.Message; ErrorReporting.WriteEm.WriteItem(SqlEx, "o7th.Class.Library.Data.Access.ExecuteWithReturn", _Msg); return default(T); } catch (Exception ex) { _Msg += "Access.ExecuteWithReturn Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.ExecuteWithReturn", _Msg); return default(T); } } /// <summary> /// Prepare our parameters, adding them and forcing a valid data length /// </summary> /// <param name="objCmd"></param> protected void PrepareParams(SqlCommand objCmd) { try { // set our initial Data Size int _DataSize = 0; // get the number of Parameter Values passed in int _PCt = _PVs.GetUpperBound(0); // begin array check Type _t_dt = _DTs.GetType(); // start looping over our parameters for (int i = 0; i <= _PCt; ++i) { // make sure that the data types are actually an array if (_t_dt.IsArray) { // select which datatype, and force the official size switch ((int)_DTs[i]) { case 0: case 33: case 6: case 9: case 13: case 19: _DataSize = 8; break; case 1: case 3: case 7: case 10: case 12: case 21: case 22: case 23: case 25: _DataSize = _PVs[i].ToString().Length; break; case 2: case 20: _DataSize = 1; break; case 5: _DataSize = 17; break; case 8: case 17: case 15: _DataSize = 4; break; case 14: _DataSize = 16; break; case 31: _DataSize = 3; break; case 32: _DataSize = 5; break; case 16: _DataSize = 2; break; } // add our parameter to the command object objCmd.Parameters.Add(_PNs[i], _DTs[i], _DataSize).Value = _PVs[i]; } else { // if the datatypes were not set, try to add them generically objCmd.Parameters.AddWithValue(_PNs[i], _PVs[i]); } } // clean up _PNs = null;_PVs = null;_DTs = null; } catch (Exception ex) { _Msg += "Access.PrepareParams Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.PrepareParams", _Msg); } } #region "Dispose Support" protected virtual void Dispose(bool disposing) { if (!disposedValue && disposing) { try { _Qry = string.Empty; _Rdr.Close(); _Rdr.Dispose(); _Cmd.Connection.Close(); _Conn.Close(); _Cmd.Dispose(); _Conn.Dispose(); _Msg = null; } catch(Exception ex) { ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.Dispose", ""); } } disposedValue = true; } public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } #endregion } }
AccessAsync.cs
using System; using System.Data; using System.Data.SqlClient; using System.Threading.Tasks; namespace o7th.Class.Library.Data { internal class AccessAsync : IDisposable { #region "Properties" // Set the type of query we are running private CommandType _QT; internal CommandType QueryType { set { _QT = value; } } // Set the actual query text to run private string _Qry; internal string Query { set { _Qry = value; } } // Set the parameter names if there are any private string[] _PNs; internal string[] ParameterNames { set { _PNs = value; } } // Set the parameter values if there are any private object[] _PVs; internal object[] ParameterValues { set { _PVs = value; } } // Set the actual Sql Data Types if there are any private System.Data.SqlDbType[] _DTs; internal System.Data.SqlDbType[] ParameterDataTypes { set { _DTs = value; } } // Check to see if there are any parameters passed private bool AreParams() { // Check to see if the values and names are null first if (_PVs != null && _PNs != null) { try { Type _t_pv = _PVs.GetType(); Type _t_pn = _PNs.GetType(); if (_t_pv.IsArray && _t_pn.IsArray) { return (_PVs.Length > 0 && _PNs.Length > 0) ? true : false; } else { return false; } } catch { // yes I meant to do this, we really don't need to get the exception here return false; } } else { return false; } } // Get a return message if any private string _Msg; internal string Message { get { return _Msg; } } // Get the connection string from our class assemblies settings internal string _ConnString { get { return Properties.Settings.Default.ConnectionString; } } // Set the official Sql Reader object private SqlDataReader _Rdr; // Set the official Sql Connection object private SqlConnection _Conn; // Set the official Sql Command object private SqlCommand _Cmd; // Hack for seeing if we're disposed already private bool disposedValue; #endregion // Constructor internal AccessAsync() { Invoke(); } // Official Constructor. We can thread these 2 becuase they are not being used yet, and it makes it slightly more efficient internal void Invoke() { try { Parallel.Invoke(() => { _Conn = new SqlConnection(_ConnString); }, () => { _Cmd = new SqlCommand(); }); } catch (Exception ex) { _Msg = "Access.Invoke Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.Invoke", _Msg); } } /// <summary> /// Return a SqlDataReader based on the properties passed to this class /// </summary> /// <returns></returns> internal async Task<SqlDataReader> GetResults() { try { // check for parameters if (AreParams()) { PrepareParams(_Cmd); } // set our connection _Cmd.Connection = _Conn; // set the type of query to run _Cmd.CommandType = _QT; // set the actual query to run _Cmd.CommandText = _Qry; // open the connection await _Cmd.Connection.OpenAsync(); // prepare the command with any parameters that may have gotten added _Cmd.Prepare(); // Execute the SqlDataReader, and set the connection to close once returned _Rdr = await _Cmd.ExecuteReaderAsync(CommandBehavior.CloseConnection); // clear out any parameters _Cmd.Parameters.Clear(); // return our reader object return (!_Rdr.HasRows) ? null : _Rdr; } catch (SqlException SqlEx) { _Msg += "Acccess.GetResults SqlException: " + SqlEx.Message; ErrorReporting.WriteEm.WriteItem(SqlEx, "o7th.Class.Library.Data.Access.GetResults", _Msg); return null; } catch (Exception ex) { _Msg += "Acccess.GetResults Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.GetResults", _Msg); return null; } } /// <summary> /// Execute a non-return query, and return the success /// </summary> /// <returns></returns> internal bool Execute() { try { // check for parameters if (AreParams()) { PrepareParams(_Cmd); } // set our connection _Cmd.Connection = _Conn; // set the type of query to run _Cmd.CommandType = _QT; // set the actual query to run _Cmd.CommandText = _Qry; // open the connection _Cmd.Connection.OpenAsync(); // prepare the command with any parameters that may have gotten added _Cmd.Prepare(); // execute the non-returnable query against the database _Cmd.ExecuteNonQueryAsync(); // clear out any parameters _Cmd.Parameters.Clear(); // executed successfully (otherwise would have thrown an exception) return true; } catch (SqlException SqlEx) { _Msg += "Access.Execute SqlException: " + SqlEx.Message; ErrorReporting.WriteEm.WriteItem(SqlEx, "o7th.Class.Library.Data.Access.Execute", _Msg); return false; } catch (Exception ex) { _Msg += "Access.Execute Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.Execute", _Msg); return false; } } /// <summary> /// Prepare our parameters, adding them and forcing a valid data length /// </summary> /// <param name="objCmd"></param> protected void PrepareParams(SqlCommand objCmd) { try { // set our initial Data Size int _DataSize = 0; // get the number of Parameter Values passed in int _PCt = _PVs.GetUpperBound(0); // begin array check Type _t_dt = _DTs.GetType(); // start looping over our parameters for (int i = 0; i <= _PCt; ++i) { // make sure that the data types are actually an array if (_t_dt.IsArray) { // select which datatype, and force the official size switch ((int)_DTs[i]) { case 0: case 33: case 6: case 9: case 13: case 19: _DataSize = 8; break; case 1: case 3: case 7: case 10: case 12: case 21: case 22: case 23: case 25: _DataSize = _PVs[i].ToString().Length; break; case 2: case 20: _DataSize = 1; break; case 5: _DataSize = 17; break; case 8: case 17: case 15: _DataSize = 4; break; case 14: _DataSize = 16; break; case 31: _DataSize = 3; break; case 32: _DataSize = 5; break; case 16: _DataSize = 2; break; } // add our parameter to the command object objCmd.Parameters.Add(_PNs[i], _DTs[i], _DataSize).Value = _PVs[i]; } else { // if the datatypes were not set, try to add them generically objCmd.Parameters.AddWithValue(_PNs[i], _PVs[i]); } } // clean up _PNs = null; _PVs = null; _DTs = null; } catch (Exception ex) { _Msg += "Access.PrepareParams Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.PrepareParams", _Msg); } } #region "Dispose Support" protected virtual void Dispose(bool disposing) { if (!disposedValue && disposing) { try { _Qry = string.Empty; _Rdr.Close(); _Rdr.Dispose(); _Cmd.Connection.Close(); _Conn.Close(); _Cmd.Dispose(); _Conn.Dispose(); _Msg = null; } catch (Exception ex) { ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Access.Dispose", ""); } } disposedValue = true; } public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } #endregion } }
Wrapper.cs
using System; using System.Collections.Generic; using System.Data.Common; namespace o7th.Class.Library.Data { /// </p> <summary> /// Wrapper class for our data access /// </summary> <p> public class Wrapper { /// </p> <summary> /// Setup our return message if any /// </summary> <p> public static string Message { set { _Msg = value; } get { return _Msg; } } private static string _Msg; // Instantiate our caching methods internal static Common.CustomCache _Cache = new Common.CustomCache(); // Map our datareader object to a strongly typed list private static IList<T> Map<T>(DbDataReader dr) where T : new() { try { // initialize our returnable list List<T> list = new List<T>(); // fire up the lamda mapping var converter = new Converter<T>(dr); while (dr.Read()) { // read in each row, and properly map it to our T object var obj = converter.CreateItemFromRow(); // add it to our list list.Add(obj); } // reutrn it return list; } catch (Exception ex) { // Catch an exception if any, an write it out to our logging mechanism, in addition to adding it our returnable message property _Msg += "Wrapper.Map Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Wrapper.Map", _Msg); // make sure this method returns a default List return default(List<T>); } } /// </p> <summary> /// Get the results of a stronly-typed IList Object /// </summary> <p> /// <typeparam name="T">Strongly-Typed class of objects that should be returned</typeparam> /// <param name="_Qry">The query to run</param> /// <param name="_QryType">The Query Type to run</param> /// <param name="_ParamNames">The Parameters' names to pass to the query, if any</param> /// <param name="_ParamVals">The Parameters' values to pass to the query, if any</param> /// <param name="_ParamDTs">The Parameters' data types to pass to the query, if any</param> /// <param name="_ShouldCache">Should we cache the response</param> /// <param name="_CacheID">Cache item name</param> /// <returns>Strongly Typed ilist of objects</returns> public static IList<T> GetResults<T>(string _Qry, System.Data.CommandType _QryType, string[] _ParamNames = null, object[] _ParamVals = null, System.Data.SqlDbType[] _ParamDTs = null, bool _ShouldCache = false, string _CacheID = "") where T : new() { // Create a reference to a potential already cached IList IList<T> _CachedItem = _Cache.Get<IList<T>>(_CacheID); // If we're already cached, there's no need to fire up the data access objects, so return the cached item instead if (_CachedItem != null && _ShouldCache) { return _CachedItem; } else { // Fire up our data access object using (Access db = new Access()) { try { // create a new ilist reference of our strongly typed class IList<T> _Query = default(IList<T>); // set the query type db.QueryType = _QryType; // set the query text db.Query = _Qry; // make sure we've got some parameters, if we do the set them to our db access object if (_ParamNames != null) { // set the parameter names db.ParameterNames = _ParamNames; // set the parameter values db.ParameterValues = _ParamVals; // set the parameter data types db.ParameterDataTypes = _ParamDTs; } // start using our db access :) Fire off the GetResults method and return back a SqlDataReader to work on using (DbDataReader r = db.GetResults()) { // make sure the data reader actually exists and contains some results if (r != null) { // map the data reader to our strongly type(s) _Query = Map<T>(r); } } // check if we should cache the results if (_ShouldCache) { // if so, set the query object to the cache _Cache.Set<IList<T>>(_Query, _CacheID); } // return our strongly typed list return _Query; } catch (Exception ex) { // Catch an exception if any, an write it out to our logging mechanism, in addition to adding it our returnable message property _Msg += "Wrapper.GetResults Exception: " + ex.Message + db.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Wrapper.GetResults", _Msg); // make sure this method returns a default List return default(IList<T>); } } } } /// </p> <summary> /// Execute a query against the database. Usually used for IUD Operations /// </summary> <p> /// <param name="_Qry">The query to execute</param> /// <param name="_QryType">The Query Type to run</param> /// <param name="_ParamNames">The Parameters' names to pass to the query, if any</param> /// <param name="_ParamVals">The Parameters' values to pass to the query, if any</param> /// <param name="_ParamDTs">The Parameters' data types to pass to the query, if any</param> /// <returns>Boolean of success</returns> public static bool Execute(string _Qry, System.Data.CommandType _QryType, string[] _ParamNames = null, object[] _ParamVals = null, System.Data.SqlDbType[] _ParamDTs = null) { // setup a reference for our success return bool _T; // Fire up our data access object using (Access db = new Access()) { try { // set the query type db.QueryType = _QryType; // set the query text db.Query = _Qry; // make sure we've got some parameters, if we do the set them to our db access object if (_ParamNames != null) { // set the parameter names db.ParameterNames = _ParamNames; // set the parameter values db.ParameterValues = _ParamVals; // set the parameter data types db.ParameterDataTypes = _ParamDTs; } // execute the query and return if it was successful or not _T = db.Execute(); // return it return _T; } catch (Exception ex) { // Catch an exception if any, an write it out to our logging mechanism, in addition to adding it our returnable message property _Msg += "Wrapper.Execute Exception: " + ex.Message + db.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Wrapper.Execute", _Msg); // make sure this method returns a default value of false return false; } } } /// </p> <summary> /// Executes a query against the database, and returns a value /// </summary> <p> /// <typeparam name="T">Strongly Typed Object for return</typeparam> /// <param name="_Qry">The query to execute</param> /// <param name="_QryType">The Query Type to run</param> /// <param name="_ParamNames">The Parameters' names to pass to the query, if any</param> /// <param name="_ParamVals">The Parameters' values to pass to the query, if any</param> /// <param name="_ParamDTs">The Parameters' data types to pass to the query, if any</param> /// <param name="_DefVal">Default value that should get returned if none are</param> /// <returns>Strongly Typed object from the query executed</returns> public static T ExecuteWithReturn<T>(string _Qry, System.Data.CommandType _QryType, string[] _ParamNames = null, object[] _ParamVals = null, System.Data.SqlDbType[] _ParamDTs = null, object _DefVal = null) where T : new() { // setup a new reference to T T _T; // Fire up our data access object using (Access db = new Access()) { try{ // set the query type db.QueryType = _QryType; // set the query text db.Query = _Qry; // make sure we've got some parameters, if we do the set them to our db access object if (_ParamNames != null) { // set the parameter names db.ParameterNames = _ParamNames; // set the parameter values db.ParameterValues = _ParamVals; // set the parameter data types db.ParameterDataTypes = _ParamDTs; } // execute the query and return the results back to _T _T = db.ExecuteWithReturn<T>((T)_DefVal); // return it return (_T is DBNull) ? default(T) : _T; } catch (Exception ex) { // Catch an exception if any, an write it out to our logging mechanism, in addition to adding it our returnable message property _Msg += "Wrapper.ExecuteWithReturn Exception: " + ex.Message + db.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Wrapper.ExecuteWithReturn", _Msg); // return the default value for the strong typed object return default(T); } } } } }
WrapperAsync.cs
using System; using System.Collections.Generic; using System.Data.Common; using System.Threading.Tasks; namespace o7th.Class.Library.Data { /// </p> <summary> /// Wrapper class for our data access, only allows a resultset and an execution, does not contain ExecuteWithReturn /// </summary> <p> public class WrapperAsync { /// </p> <summary> /// Setup our return message if any /// </summary> <p> public static string Message { set { _Msg = value; } get { return _Msg; } } private static string _Msg; // Instantiate our caching methods internal static Common.CustomCache _Cache = new Common.CustomCache(); // Map our datareader object to a strongly typed list private static async Task<IList<T>> Map<T>(DbDataReader dr) where T : new() { try { // initialize our returnable list List<T> list = new List<T>(); // fire up the lamda mapping var converter = new Converter<T>(dr); while (await dr.ReadAsync()) { // read in each row, and properly map it to our T object var obj = converter.CreateItemFromRow(); // add it to our list list.Add(obj); } // reutrn it return list; } catch (Exception ex) { // Catch an exception if any, an write it out to our logging mechanism, in addition to adding it our returnable message property _Msg += "Wrapper.Map Exception: " + ex.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Wrapper.Map", _Msg); // make sure this method returns a default List return default(IList<T>); } } /// </p> <summary> /// Get the results of a stronly-typed IList Object Asyncronously /// </summary> <p> /// <typeparam name="T">Strongly-Typed class of objects that should be returned</typeparam> /// <param name="_Qry">The query to run</param> /// <param name="_QryType">The Query Type to run</param> /// <param name="_ParamNames">The Parameters' names to pass to the query, if any</param> /// <param name="_ParamVals">The Parameters' values to pass to the query, if any</param> /// <param name="_ParamDTs">The Parameters' data types to pass to the query, if any</param> /// <param name="_ShouldCache">Should we cache the response</param> /// <param name="_CacheID">Cache item name</param> /// <returns>Strongly Typed ilist of objects</returns> public static IList<T> GetResults<T>(string _Qry, System.Data.CommandType _QryType, string[] _ParamNames = null, object[] _ParamVals = null, System.Data.SqlDbType[] _ParamDTs = null, bool _ShouldCache = false, string _CacheID = "") where T : new() { // Create a reference to a potential already cached IList IList<T> _CachedItem = _Cache.Get<IList<T>>(_CacheID); // If we're already cached, there's no need to fire up the data access objects, so return the cached item instead if (_CachedItem != null && _ShouldCache) { return _CachedItem; } else { // Fire up our data access object using (AccessAsync db = new AccessAsync()) { try { // create a new ilist reference of our strongly typed class IList<T> _Query = null; // set the query type db.QueryType = _QryType; // set the query text db.Query = _Qry; // make sure we've got some parameters, if we do the set them to our db access object if (_ParamNames != null) { // set the parameter names db.ParameterNames = _ParamNames; // set the parameter values db.ParameterValues = _ParamVals; // set the parameter data types db.ParameterDataTypes = _ParamDTs; } // start using our db access :) Fire off the GetResults method and return back a SqlDataReader to work on using (DbDataReader r = db.GetResults().Result) { // make sure the data reader actually exists and contains some results if (r != null) { // map the data reader to our strongly type(s) _Query = Map<T>(r).Result; } } // check if we should cache the results if (_ShouldCache) { // if so, set the query object to the cache _Cache.Set<IList<T>>(_Query, _CacheID); } // return our strongly typed list return _Query; } catch (Exception ex) { // Catch an exception if any, an write it out to our logging mechanism, in addition to adding it our returnable message property _Msg += "Wrapper.GetResults Exception: " + ex.Message + db.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Wrapper.GetResults", _Msg); // make sure this method returns a default List return default(IList<T>); } } } } /// </p> <summary> /// Execute a query against the database. Usually used for IUD Operations /// </summary> <p> /// <param name="_Qry">The query to execute</param> /// <param name="_QryType">The Query Type to run</param> /// <param name="_ParamNames">The Parameters' names to pass to the query, if any</param> /// <param name="_ParamVals">The Parameters' values to pass to the query, if any</param> /// <param name="_ParamDTs">The Parameters' data types to pass to the query, if any</param> /// <returns>Boolean of success</returns> public static bool Execute(string _Qry, System.Data.CommandType _QryType, string[] _ParamNames = null, object[] _ParamVals = null, System.Data.SqlDbType[] _ParamDTs = null) { // setup a reference for our success return bool _T; // Fire up our data access object using (AccessAsync db = new AccessAsync()) { try { // set the query type db.QueryType = _QryType; // set the query text db.Query = _Qry; // make sure we've got some parameters, if we do the set them to our db access object if (_ParamNames != null) { // set the parameter names db.ParameterNames = _ParamNames; // set the parameter values db.ParameterValues = _ParamVals; // set the parameter data types db.ParameterDataTypes = _ParamDTs; } // execute the query and return if it was successful or not _T = db.Execute(); // return it return _T; } catch (Exception ex) { // Catch an exception if any, an write it out to our logging mechanism, in addition to adding it our returnable message property _Msg += "Wrapper.Execute Exception: " + ex.Message + db.Message; ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Wrapper.Execute", _Msg); // make sure this method returns a default value of false return false; } } } } }
Converter.cs
using System; using System.Collections.Generic; using System.Data; using System.Linq; using System.Linq.Expressions; using System.Reflection; namespace o7th.Class.Library.Data { /// </p> <summary> /// Converter class to convert returned Sql Records to strongly typed classes /// </summary> <p> /// <typeparam name="T">Type of the object we'll convert too</typeparam> internal class Converter<T> where T : new() { // Declare our _converter delegate readonly Func<IDataReader, T> _converter; // Declare our internal dataReader readonly IDataReader dataReader; // Build our mapping based on the properties in the class/type we've passed in to the class private Func<IDataReader, T> GetMapFunc() { try { // declare our field count int _fc = dataReader.FieldCount; // declare our expression list List<Expression> exps = new List<Expression>(); // build our parameters for the expression tree ParameterExpression paramExp = Expression.Parameter(typeof(IDataRecord)); ParameterExpression targetExp = Expression.Variable(typeof(T)); // Add our expression tree assignment to the exp list exps.Add(Expression.Assign(targetExp, Expression.New(targetExp.Type))); //does int based lookup PropertyInfo indexerInfo = typeof(IDataRecord).GetProperty("Item", new[] { typeof(int) }); // grab a collection of column names from our data reader var columnNames = Enumerable.Range(0, _fc).Select(i => new { i, name = dataReader.GetName(i)}).AsParallel(); // loop through all our columns and map them properly foreach (var column in columnNames) { var property = targetExp.Type.GetProperty(column.name, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase); if (property == null) continue; // build our expression tree to map the column to the T ConstantExpression columnIndexExp = Expression.Constant(column.i); IndexExpression cellExp = Expression.MakeIndex(paramExp, indexerInfo, new[] { columnIndexExp }); // Column value expression ParameterExpression cellValueExp = Expression.Variable(typeof(object)); // Check for nulls, and set a default property value ConditionalExpression convertExp = Expression.Condition(Expression.Equal(cellValueExp, Expression.Constant(DBNull.Value)), Expression.Default(property.PropertyType), Expression.Convert(cellValueExp, property.PropertyType)); // set the value/column/type exression BlockExpression cellValueReadExp = Expression.Block(new[] { cellValueExp }, Expression.Assign(cellValueExp, cellExp), convertExp); // Assign the property/value to our expression BinaryExpression bindExp = Expression.Assign(Expression.Property(targetExp, property), cellValueReadExp); // add it to our expression list exps.Add(bindExp); } // add the originating map to our expression list exps.Add(targetExp); // return a compiled cached map return Expression.Lambda<Func<IDataReader, T>>(Expression.Block(new[] { targetExp }, exps), paramExp).Compile(); } catch (Exception ex) { ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Converter.GetMapFunc", ex.Message); return default(Func<IDataReader, T>); } } // initialize internal Converter(IDataReader dataReader) { // initialize the internal datareader this.dataReader = dataReader; // build our map _converter = GetMapFunc(); } // create and map each column to it's respective object internal T CreateItemFromRow() { try { // convert the datareader record to our map return _converter(dataReader); } catch (DataException dex) { ErrorReporting.WriteEm.WriteItem(dex, "o7th.Class.Library.Data.Converter.CreateItemFromRow-DB", dex.Message); return default(T); } catch (Exception ex) { ErrorReporting.WriteEm.WriteItem(ex, "o7th.Class.Library.Data.Converter.CreateItemFromRow", ex.Message); return default(T); } } } }
Used properly these classes will allow you to map your strongly typed classes to the SqlDataReader object, to which you could even convert that into just a DataReader… but ehh.
SIDE NOTE:  You’ll need to come up with your own error reporting 😉
Happy Coding!
~Kevin