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Cosmos DB - CreateCollectionIfNotExistsAsync Generic method

I am using cosmos DB and I have created below generic repository for CRUD operations.
public class CosmosDBRepository : ICosmosDBRepository
{
private readonly DocumentClient _client;
private readonly string DatabaseId = "FleetHub";
public CosmosDBRepository()
{
var endpoint = CloudConfigurationManager.GetSetting("CosmoDbEndpoint");
var authkey = CloudConfigurationManager.GetSetting("CosmoDbAuthKey");
try
{
if (endpoint == null || authkey == null)
{
throw new ArgumentNullException("CosmoDbEndpoint or CosmoDbAuthKey could not be found in the config file, check your settings.");
}
if (_client == null)
{
_client = new DocumentClient(new Uri(endpoint), authkey, connectionPolicy: new ConnectionPolicy { EnableEndpointDiscovery = false });
}
CreateDatabaseIfNotExistsAsync().Wait();
CreateCollectionIfNotExistsAsync().Wait();
}
catch (Exception e)
{
throw new Exception($"Initialise failed CosmoDbEndpoint {endpoint} or CosmoDbAuthKey {authkey} could not be found in the config file, check your settings. {e.Message}");
}
}
/// <summary>
///
/// </summary>
/// <param name="id"></param>
/// <param name="partitionkey"></param>
/// <returns></returns>
public async Task<T> GetItemAsync<T>(string id, string partitionkey) where T : class
{
try
{
string CollectionId = GetAttributeCosmoDbCollection<T>(typeof(T));
Document document = await _client.ReadDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id), new RequestOptions { PartitionKey = new PartitionKey(partitionkey) });
return (T)(dynamic)document;
}
catch (DocumentClientException e)
{
if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
{
return null;
}
else
{
throw;
}
}
}
/// <summary>
///
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
public async Task<Document> CreateItemAsync<T>(T item) where T : class
{
string CollectionId = GetAttributeCosmoDbCollection<T>(typeof(T));
return await _client.CreateDocumentAsync(UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId), item);
}
public async Task<IEnumerable<T>> GetItemsAsync<T>(Expression<Func<T, bool>> predicate, Expression<Func<T, object>> orderByDesc, int takeCount = -1)
where T : class
{
string CollectionId = GetAttributeCosmoDbCollection<T>(typeof(T));
var criteria = _client.CreateDocumentQuery<T>(
UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId), new FeedOptions { EnableCrossPartitionQuery = true })
.Where(predicate)
.OrderByDescending(orderByDesc)
.AsDocumentQuery();
IDocumentQuery<T> query = criteria;
List<T> results = new List<T>();
while (query.HasMoreResults)
{
if (takeCount > -1 && results.Count >= takeCount)
{
break;
}
results.AddRange(await query.ExecuteNextAsync<T>());
}
return results;
}
/// <summary>
///
/// </summary>
/// <param name="id"></param>
/// <param name="item"></param>
/// <returns></returns>
public async Task<Document> UpdateItemAsync<T>(string id, T item) where T : class
{
string CollectionId = GetAttributeCosmoDbCollection<T>(typeof(T));
return await _client.ReplaceDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id), item);
}
#region private methods
private async Task CreateDatabaseIfNotExistsAsync()
{
try
{
await _client.ReadDatabaseAsync(UriFactory.CreateDatabaseUri(DatabaseId));
}
catch (DocumentClientException e)
{
if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
{
await _client.CreateDatabaseAsync(new Database { Id = DatabaseId });
}
else
{
throw;
}
}
}
/// <summary>
///
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
private string GetPartitionKeyAttributeCosmoDbCollection(Type t)
{
// Get instance of the attribute.
CosmoDBCollection attribute =
(CosmoDBCollection)Attribute.GetCustomAttribute(t, typeof(CosmoDBCollection));
if (attribute == null)
{
throw new Exception("The attribute CosmoDbCollection was not found.");
}
return attribute.PartitionKey;
}
private string GetAttributeCosmoDbCollection<T>(Type t) where T : class
{
// Get instance of the attribute.
CosmoDBCollection attribute =
(CosmoDBCollection)Attribute.GetCustomAttribute(t, typeof(CosmoDBCollection));
if (attribute == null)
{
throw new Exception("The attribute CosmoDbCollection was not found.");
}
return attribute.Name;
}
#endregion
}
Here is CosmoDBCollection class:
public class CosmoDBCollection : Attribute
{
public string Name { get; set; }
public string PartitionKey { get; set; }
}
I am calling CreateCollectionIfNotExistsAsync().Wait(); in the constructor and this method required collectionId. How Can I pass CollectionId to this method? As this is the generic repository.
Do I need to create a Generic CreateCollectionIfNotExistsAsync() method?

If your collection name is based off <T>, why not simply have CosmosDBRepository<T> as the actual class. That way you can get the value also on the constructor.
Ideally it would also be a readonly private property that you only calculate once (on the constructor) and reuse on all operations to avoid paying the cost to construct it later on (since it doesn't change).

SQLite Implementation in VS 2019

I'm still really new to coding and trying to make my first WPF application. I have been trying to implement sqlite for the past like 3 days now.
I am using VS 2019. I have downloaded the SQLite Toolbox and am following the instructions here - https://github.com/ErikEJ/SqlCeToolbox/wiki/EF6-workflow-with-SQLite-DDEX-provider. I did a full installation. Was I supposed to install it in my project directory? Because now I just have a bunch of files and nothing seems to have changed in Studio. I tried using Install.exe, but it returned a "confirm option not enabled" error. Looking at a similar question, I tried putting the files in an external folder in my project, and then installed the System.Data.SQLite.EF6.dll to my GAC using the VS Dev Console. The toolbox doesn't see any changes, and does not recognize the dll and I'm having a hard time finding reliable information for my version. Thanks for any help getting pointed in the right direction!

I'm not sure why you mention toolbox as far as I'm aware you access the SQLite functionality programmatically.
The NuGet packages that I recently used for a Xamarin project (SQLite-net-pcl by Frank Krueger and supporting libraries) allowed me to use pretty simple object mapping without recourse to SQL like strings.
I use a lot of interfaces in my code, but here's my all access database class
:
public class AllAccessDataTableBaseSqLite<T> : IDataAccessRead<T>, IDataAccessWrite<T>,IDataAccessExpressionSearch<T>, IDataAccessDelete<T> where T: IDataRecord, new()
{
//Note that this static value will only apply to those classes based on the same generic type e.g. all DataTableBase<User> instances etc.
public static SQLiteAsyncConnection DBConnection;
/// <summary>
/// Lock object to prevent multi-thread interruption of code segment.
/// </summary>
public static readonly object CollisionLock = new object();
/// <summary>
/// Constructor
/// </summary>
public AllAccessDataTableBaseSqLite()
{
lock (CollisionLock)
{
if (DBConnection != null)
{
DBConnection.CreateTableAsync<T>().Wait();
return;
}
try
{
string directory;
if (DeviceInfo.Platform != DevicePlatform.Unknown)
{
directory = FileSystem.AppDataDirectory;
}
else
{
directory = "DataStore";
var directoryInfo = Directory.CreateDirectory(directory);
directory = directoryInfo.FullName;
}
var path = Path.Combine(directory, $"{typeof(T).Name}.db");
if (!File.Exists(path))
{
using var fileStream = File.Create(path);
fileStream.Close();
}
DBConnection = new SQLiteAsyncConnection(path);
DBConnection.CreateTableAsync<T>().Wait();
}
catch (Exception ex)
{
if (ex is UnauthorizedAccessException)
{
}
}
}
}
/// <summary>
/// Create the data table
/// </summary>
/// <returns></returns>
public async Task<CreateTableResult> CreateTableAsync()
{
if (DBConnection != null)
{
return await DBConnection.CreateTableAsync<T>();
}
return CreateTableResult.Migrated;
}
/// <summary>
/// Create a new record entry
/// </summary>
/// <param name="entity">Data entity to enter</param>
/// <param name="user">Current User information</param>
/// <returns>New entry record if successful</returns>
public async Task<T> CreateAsync(T entity, IUserRecord user)
{
if (entity == null)
{
return default(T);
}
if (DBConnection == null)
{
return default(T);
}
entity.CreatedDate = DateTime.UtcNow;
entity.CreatedByUserId = user.Id;
entity.Id = 0;
try
{
await DBConnection.InsertAsync(entity);
}
catch (SQLiteException e)
{
if (e.Message == "Constraint")
{
throw new InvalidConstraintException(e.Message, e.InnerException);
}
}
var result = entity;
return result;
}
/// <summary>
/// Update a collection of new entities of type T to the data table.
/// All entities should be present within the data table
/// </summary>
/// <param name="entityList">Entity collection</param>
/// <param name="user">user making the change</param>
/// <returns>ID of entities successfully updated or added</returns>
public async Task<int> UpdateAllAsync(IEnumerable<T> entityList, IUserRecord user)
{
var result = 0;
foreach (var t in entityList)
{
if (null != await UpdateAsync(t, user))
{
result++ ;
}
}
return result;
}
/// <summary>
/// Obtain the data record with the given Id
/// </summary>
/// <param name="id">Id value to select the record by</param>
/// <returns>A valid record if found otherwise null</returns>
public async Task<T> GetById(int id)
{
if (DBConnection == null)
{
return default(T);
}
return await DBConnection.Table<T>().Where(i => i.Id == id).FirstOrDefaultAsync();
}
/// <summary>
/// This function returns all database entries that are not marked deleted or changed
/// Warning: The data set may be very large
/// </summary>
/// <returns>A list of entries</returns>
public async Task<List<T>> GetAll()
{
if (DBConnection != null)
{
return await DBConnection.Table<T>().Where(x=>x.ChangedDate==default && x.DeletedDate==default)
.ToListAsync();
}
return new List<T>();
}
/// <inheritdoc />
public async Task<List<T>> GetAllHistoric() => await DBConnection.Table<T>().ToListAsync();
/// <summary>
/// This function is used to update the supplied record entry within the database.
/// If the supplied record does not have a non-zero value Id field it is assumed to be a
/// new record to be inserted into the database.
/// </summary>
/// <param name="entity">Record to update</param>
/// <param name="user">User performing the action</param>
/// <returns></returns>
public async Task<T> UpdateAsync(T entity, IUserRecord user)
{
if (DBConnection == null)
{
return default(T);
}
if (entity == null)
{
return default(T);
}
var newRecord = (T) ((entity) as BaseRecord<T>)?.Clone();
if (null == newRecord)
{
return default(T);
}
//if Id is zero assume that the record is new and to be added
if (newRecord.Id == 0)
{
if (user != null)
{
newRecord.CreatedByUserId = user.Id;
}
newRecord.CreatedDate = DateTime.UtcNow;
newRecord.Id = await DBConnection.InsertAsync(newRecord);
return newRecord;
}
// Id is not zero and thus a new record should be created linked to the old record.
var oldRecord = await GetById(newRecord.Id);
oldRecord.ChangedDate = DateTime.UtcNow;
if (user != null)
{
oldRecord.ChangedByUserId = user.Id;
}
try
{
var result = await DBConnection.UpdateAsync(oldRecord);
}
catch (Exception e)
{
Debug.WriteLine($"UpdateAsync {e.Message}");
}
newRecord.PreviousRecordId = oldRecord.Id;
newRecord.Id = 0;
return await CreateAsync(newRecord, user);
}
/// <inheritdoc />
public async Task<int> DeleteAsync(T entity)
{
if (DBConnection == null)
{
return -1;
}
return await DBConnection.DeleteAsync(entity);
}
/// <inheritdoc />
public async Task DeleteAll()
{
await DBConnection.DropTableAsync<T>();
await CreateTableAsync();
}
/// <inheritdoc />
public async Task<PagedResult<T>> GetAllPagedResult(int recordId, uint maxResults = 100)
{
if (DBConnection == null)
{
return null;
}
List<T> list;
if (maxResults == 0)
{
list = await GetAll();
}
else
{
list = await DBConnection.Table<T>().Where(x => (x.Id >= recordId && x.ChangedDate == default && x.DeletedDate == default)).ToListAsync();
if (list.Count() > maxResults)
{
list = list.GetRange(0, (int) maxResults);
}
}
return new PagedResult<T>(list, list.Count());
}
/// <inheritdoc />
public async Task<IEnumerable<T>> FindAsyncOrdered<TValue>(Expression<Func<T, bool>> predicate = null,
Expression<Func<T, TValue>> orderBy = null)
{
var query = DBConnection.Table<T>();
if (predicate != null)
{
query = query.Where(predicate);
}
if (orderBy != null)
{
query = query.OrderBy<TValue>(orderBy);
}
return await query.ToListAsync();
}
/// <inheritdoc />
public async Task<T> FindFirst(Expression<Func<T, bool>> predicate) => await DBConnection.FindAsync(predicate);
}
I'm using data classes based upon:
public interface IDataRecord
{
/// <summary>
/// Identifier for record
/// </summary>
int Id { get; set; }
/// <summary>
/// Link to previous version of record
/// </summary>
int PreviousRecordId { get; set; }
/// <summary>
/// User Identity that made the change
/// </summary>
int ChangedByUserId { get; set; }
/// <summary>
/// Date when the data record was last changed
/// </summary>
DateTime ChangedDate { get; set; }
/// <summary>
/// Identity of User that deleted the record
/// </summary>
int DeletedByUserId { get; set; }
/// <summary>
/// Date when the data record was deleted
/// </summary>
DateTime DeletedDate { get; set; }
/// <summary>
/// Identity of User that created the record
/// </summary>
int CreatedByUserId { get; set; }
/// <summary>
/// Date when the data record was added
/// </summary>
DateTime CreatedDate { get; set; }
object Clone();
}
Obviously you don't have to use this, but put simply for my application implementation each type of data record is stored in its own data file (thus 1 table per file) and this is created at the beginning in the constructor.
The SQLite db connection is created using the data file path.
Table is created using the dbconnection
edit
I've had a closer look at your code.
Points to note are:
You don't appear to be creating a table.
Access to non-app folders is restricted if you chose to create a UWP rather than base WPF project - be aware of folder access permissions when running apps especially in release mode.

Redis Publish Subscribe does not work properly

I am not able to get advantage from the pub/sub StackExchange.Redis features.
This is my code.
Console application
using StackExchange.Redis;
using System;
using System.Data;
namespace RedisHashSets
{
class Program
{
static void Main(string[] args)
{
#region Prepare Data
var exampleData = new DataTable();
exampleData.Columns.Add("session_guid", typeof(String));
exampleData.Columns.Add("status_code", typeof(String));
exampleData.Columns.Add("date_open", typeof(DateTime));
exampleData.Columns.Add("date_expiry", typeof(DateTime));
exampleData.Columns.Add("extra_id", typeof(long));
exampleData.Columns.Add("current_real_balance", typeof(Decimal));
DataRow row = exampleData.NewRow();
row[0] = Guid.NewGuid();
row[1] = 1;
row[2] = DateTime.Now;
row[3] = DateTime.Now.AddMinutes(30);
row[4] = 44567;
row[5] = 10.34;
exampleData.Rows.Add(row);
#endregion
var redisClient = RedisProvider.Instance;
string guid = Guid.NewGuid().ToString();
// Add an Entry
redisClient.Set(guid, RedisDataMapper.GetHashSet(exampleData)[0]);
// Modify an Entry
HashEntry entry = new HashEntry("exrta_id", 338349);
redisClient.Set(guid, entry);
// Get an Entry
HashSet val = redisClient.Get(guid);
//Invalidate the key
redisClient.redisPubSub.Publish("InvalidateBalances", guid);
}
}
}
Redis Singletone Client
namespace RedisHashSets
{
/// <summary>
/// Provide access to the Redis capabilites used to store sesion. Used as a Singleton
/// </summary>
public class RedisProvider
{
#region Private Fields
private readonly static Lazy<RedisProvider> lazyObj = new Lazy<RedisProvider>(() => new RedisProvider());
private ConnectionMultiplexer redisClient;
private IDatabase redisDatabase;
private IServer currentServer;
private EndPoint[] endPoints;
#endregion Private Fields
#region Public Fields
public static RedisProvider Instance { get { return lazyObj.Value; } }
public ISubscriber redisPubSub;
public bool IsRedisEnableByConfig { get; set; }
#endregion Public Fields
#region Public Methods
private RedisProvider()
{
if (!lazyObj.IsValueCreated)
{
var conf = RedisConfig.GetConfiguration();
if (conf is null)
{
IsRedisEnableByConfig = false;
}
else
{
IsRedisEnableByConfig = true;
redisClient = ConnectionMultiplexer.Connect(conf);
redisDatabase = redisClient.GetDatabase(0);
endPoints = redisClient.GetEndPoints();
currentServer = redisClient.GetServer(endPoints.First());
ManageSubscriber();
}
}
}
private void ManageSubscriber()
{
redisPubSub = redisClient.GetSubscriber();
redisPubSub.Subscribe(new RedisChannel("InvalidateBalances", RedisChannel.PatternMode.Pattern), (channel, message) => MessageAction(message));
}
private void MessageAction(RedisValue message)
{
HashEntry updatedEntry = new HashEntry(HashSet.IsUpdatedFlag, false);
Set(message, updatedEntry);
}
public void Set(string key, HashSet value)
{
redisDatabase.HashSet(key, value.Entries);
Set(key, value.IsUpdated);
}
public void Set(string key, HashEntry value)
{
redisDatabase.HashSet(key, value.Name, value.Value);
}
/// <summary>
/// Get a value from Redis.
/// </summary>
/// <param name="key">The key of the vaule to retrive</param>
/// <returns>Cast the value and retrurn a strongly typed object</returns>
public HashSet Get(string key)
{
HashEntry[] value = redisDatabase.HashGetAll(key);
return new HashSet(value.Length) { Entries = value };
}
/// <summary>
/// Check if a value is in stored or not expired. Time consuming. Use onky if necessary.
/// </summary>
/// <param name="key">The key of the value</param>
public bool IsInCache(string key)
{
return redisDatabase.KeyExists(key);
}
/// <summary>
/// Remove a value from the cache.
/// </summary>
/// <param name="key">The key to remove</param>
public bool Remove(string key)
{
return redisDatabase.KeyDelete(key);
}
/// <summary>
/// Return the number of active keys stored inside the redis databaase.
/// </summary>
public int GetKeysNumber()
{
var retVal = 0;
retVal = currentServer.Keys().Count();
return retVal;
}
/// <summary>
/// Return an enumerable of all the Keys.
/// </summary>
public IEnumerable<string> GetKeys()
{
return currentServer.Keys().Select(k => k.ToString());
}
#endregion
}
}
When I publish a message, it is not catched by the subscriber.
Can you help me?

Try to check you configuration.
Your code is working for me with the "localhost" as the connection string i.e
redisClient = ConnectionMultiplexer.Connect("localhost");
This is the minimal version of your code which is working for me in a console app.
using StackExchange.Redis;
using System;
using System.Linq;
using System.Net;
namespace RedisHashSets
{
class Program
{
static void Main(string[] args)
{
var redisClient = RedisProvider.Instance;
for (int i = 0; i < 10; i++)
{
//Thread.Sleep(100);
redisClient.redisPubSub.Publish("InvalidateBalances", Guid.NewGuid().ToString());
}
Console.ReadLine();
}
}
public class RedisProvider
{
#region Private Fields
private static readonly Lazy<RedisProvider> lazyObj = new Lazy<RedisProvider>(() => new RedisProvider());
private ConnectionMultiplexer redisClient;
private IDatabase redisDatabase;
private IServer currentServer;
private EndPoint[] endPoints;
public static RedisProvider Instance => lazyObj.Value;
public ISubscriber redisPubSub;
public bool IsRedisEnableByConfig { get; set; }
private RedisProvider()
{
if (!lazyObj.IsValueCreated)
{
IsRedisEnableByConfig = true;
redisClient = ConnectionMultiplexer.Connect("localhost");
endPoints = redisClient.GetEndPoints();
currentServer = redisClient.GetServer(endPoints.First());
ManageSubscriber();
}
}
private void ManageSubscriber()
{
redisPubSub = redisClient.GetSubscriber();
redisPubSub.Subscribe(new RedisChannel("InvalidateBalances", RedisChannel.PatternMode.Pattern), (channel, message) => MessageAction(message));
}
private void MessageAction(RedisValue message)
{
Console.WriteLine("msg arrived: " + message);
}
#endregion
}
}
Also please keep your code examples minimal complete and verifiable.

C# Polymorphism with Dictionaries not working as intended

I've have a a abstract Base class
public abstract class absTerminalStrategy
{
//....
}
and two child class lets call them Class A and Class B
Class A
{
//Some Params
public A (/*Some Params*/)
}
Class B
{
//Some Params
Public B (/*Some Params*/)
}
in "upper" layer class I'll call Class Control
I've those objects
{
//..
public static absTerminalStrategy terminal = null;
/// <summary>
/// stores all instencese of A_tarategy to be used --> string A_IP
/// </summary>
public static Dictionary<string, A> terminal_A_Dictionary = new Dictionary<string, A_Strategy>();
/// <summary>
/// stores all instencese of B_Scritping to be used --> string B_Port
/// </summary>
public static Dictionary<string, B> terminal_B_Dictionary = new Dictionary<string, B_trategy>();
//..
}
Now in run time I add some instances to the dictionaries and later I need to "jump" between
various instances using this method
public static bool Terminalset(string terminalName)
{
string InterfaceType = terminalName.Split(':')[0];//cutting the root name for switch
switch(InterfaceType)
{
case "A":
{
A New_A =null;
if (terminal_A_Dictionary.TryGetValue(terminalName, out New_A))//return bool
terminal = New_A;
else return false;
}
break;
case "B":
{
B New_B =null;
if (terminal_B_Dictionary.TryGetValue(terminalName, out New_B))//return bool
terminal = New_B;
else return false;
}
break;
}
return true;
}
My problem is , when I change between class A to class B everything works fine
when I change between instances of class A using the dictionary it seems to work fine
But when I do the same with Class B I doesn't work and stays on it last property to entered to he dictionary (the last new instance to entered)
what can be the problem ?
Also this is how add to the dictionary
public static bool TermialCheckCreate (TerminalType terminalType , GlobalParam.A a = null , GlobalParam.B b= null)
{
switch (terminalType)
{
case TerminalType.A:
{
if (terminal_A_Dictionary.ContainsKey(string.Format("A:{0}", _A_Param.AIp))) break;
if (a == null) return false;
A_Strategy terminal = new A_Strategy(_A_Param.AIp, GlobalParam.A_PORT, 60);
terminalTelnetDictionary.Add(string.Format("A:{0}",_A_Param.AIp), terminal);
}
break;
case TerminalType.B:
{
if (terminal_B_Dictionary.ContainsKey(string.Format("B:{0}", _B_Param.Bcom))) break;
if (b == null) return false;
B_strategy terminal = new B_Strategy(GlobalParam.AppDirectory, _B_Param.BCom, _B_Param.BRate);
terminal_B_Dictionary.Add(string.Format("B:{0}",_B_Param.BCom), terminal);
}
break;
}
return true;
}
EDIT small corrections
copy of the classes involved
class to control all the dictionaries
public enum TerminalType {serial , Telent };
public static class TerminalControl
{
/// <summary>
/// stores all instencese of TelnetStarategy to be used --> string telnetIP
/// </summary>
public static Dictionary<string, TelnetStrategy> terminalTelnetDictionary = new Dictionary<string, TelnetStrategy>();
/// <summary>
/// stores all instencese of SerialScritping to be used --> string SerailPort
/// </summary>
public static Dictionary<string, SerialStrategy> terminalSerialDictionary = new Dictionary<string, SerialStrategy>();
/// <summary>
/// abstract instance , chooses between serial and telent
/// </summary>
public static absTerminalStrategy terminal = null;
/// <summary>
/// static constructor
/// </summary>
static TerminalControl()
{
}
/// <summary>
/// Inherits from serial/telnet strategy will run this class of commands
/// </summary>
/// <param name="terminalType"></param>
/// <param name="TelnetIP"></param>
/// <param name="SerialPort"></param>
/// <param name="SerialBaudRate"></param>
/// <param name="Command"></param>
/// <returns></returns>
public static List<string> TerminalSendAndWaitForList(string Command,string terminalName,string fullpathLog="")
{
if (!Terminalset(terminalName)) return new List<string>(new string[] { "ERROR : Device Not Found !!! Check it and add" });
return terminal.SendAndWaitForList(Command);
}
public static bool Terminalset(string terminalName)
{
string InterfaceType = terminalName.Split(':')[0];
switch(InterfaceType)
{
case "Telnet":
{
TelnetStrategy NewTelnet =null;
terminal = NewTelnet;
if (terminalTelnetDictionary.TryGetValue(terminalName, out NewTelnet))//return bool
terminal = NewTelnet;
else return false;
}
break;
case "Serial":
{
SerialStrategy NewSerial =null;
terminal = NewSerial;
if (terminalSerialDictionary.TryGetValue(terminalName, out NewSerial))//return bool
terminal = NewSerial;
else return false;
}
break;
}
return true;
}
/// <summary>
/// added new terminal to inner dictionary
/// </summary>
/// <param name="terminalType"></param>
/// <param name="telentParam"></param>
/// <param name="serialParam"></param>
/// <returns></returns>
public static bool TermialCheckCreate (TerminalType terminalType , GlobalParam.TelentParams telentParam = null , GlobalParam.SerialParams serialParam= null)
{
switch (terminalType)
{
case TerminalType.Telent:
{
if (terminalTelnetDictionary.ContainsKey(string.Format("Telnet:{0}", telentParam.telnetIp))) break;
if (telentParam == null) return false;
TelnetStrategy terminal = new TelnetStrategy(telentParam.telnetIp, GlobalParam.TELNET_PORT, 60);
terminalTelnetDictionary.Add(string.Format("Telnet:{0}",telentParam.telnetIp), terminal);
}
break;
case TerminalType.serial:
{
if (terminalSerialDictionary.ContainsKey(string.Format("Serial:{0}", serialParam.SerialCom))) break;
if (serialParam == null) return false;
SerialStrategy terminal = new SerialStrategy(GlobalParam.AppDirectory, serialParam.SerialCom, serialParam.SerialBaudRate);
terminalSerialDictionary.Add(string.Format("Serial:{0}",serialParam.SerialCom), terminal);
}
break;
}
return true;
}
}
abstract base and child showing only there names and constructors (if needed i"ll publish the entire code....)
public abstract class absTerminalStrategy
{
public abstract List<string> SendAndWaitForList(string Command);
public abstract bool WaitForOutPut(string Blocker, int secTimeOut);//implement Wait for Output string before releasing lock (Monitor.wait/Pulse)
}
public class SerialStrategy : absTerminalStrategy
{
public ScriptingSerial serailAgent = null;//Infrastructure
public SerialStrategy(string fullPathLog , string PortName , int Baudrate)
{
serailAgent = new ScriptingSerial(fullPathLog, PortName, Baudrate);
}
//....
}
public class TelnetStrategy : absTerminalStrategy
{
public static event SerialDataInput_EventHandler onDataInput;
public static ScriptingTelnet telnetAgent = null;//Infrastructure
public string TelnetIp = string.Empty;
public TelnetStrategy(string Ip, int Port, int CommandTimeOut)
{
TelnetIp = Ip;
int port = Port;
telnetAgent = new ScriptingTelnet(Ip, port, CommandTimeOut);
}
}

Disable save button when validation fails

As you can likely see from the title, I am about to ask something which has been asked many times before. But still, after reading all these other questions, I cannot find a decent solution to my problem.
I have a model class with basic validation:
partial class Player : IDataErrorInfo
{
public bool CanSave { get; set; }
public string this[string columnName]
{
get
{
string result = null;
if (columnName == "Firstname")
{
if (String.IsNullOrWhiteSpace(Firstname))
{
result = "Geef een voornaam in";
}
}
if (columnName == "Lastname")
{
if (String.IsNullOrWhiteSpace(Lastname))
{
result = "Geef een familienaam in";
}
}
if (columnName == "Email")
{
try
{
MailAddress email = new MailAddress(Email);
}
catch (FormatException)
{
result = "Geef een geldig e-mailadres in";
}
}
if (columnName == "Birthdate")
{
if (Birthdate.Value.Date >= DateTime.Now.Date)
{
result = "Geef een geldige geboortedatum in";
}
}
CanSave = true; // this line is wrong
return result;
}
}
public string Error { get { throw new NotImplementedException();} }
}
This validation is done everytime the property changes (so everytime the user types a character in the textbox):
<TextBox Text="{Binding CurrentPlayer.Firstname, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Top" Width="137" IsEnabled="{Binding Editing}" Grid.Row="1"/>
This works perfect. The validation occurs (the PropertyChanged code for the binding is done in the VM on the CurrentPlayer property, which is an object of Player).
What I would like to do now is disable the save button when the validation fails.
First of all, the easiest solutions seems to be found in this thread:
Enable Disable save button during Validation using IDataErrorInfo
If I want to follow the accepted solution, I'd have to write my
validation code twice, as I cannot simply use the indexer. Writing
double code is absolutely not what I want, so that's not a solution
to my problem.
The second answer on that thread sounded very promising as first,
but the problem is that I have multiple fields that have to be
validated. That way, everything relies on the last checked property
(so if that field is filled in correctly, CanSave will be true, even
though there are other fields which are still invalid).
One more solution I've found is using an ErrorCount property. But as I'm validating at each property change (and so at each typed character), this isn't possible too - how could I know when to increase/decrease the ErrorCount?
What would be the best way to solve this problem?
Thanks

This article http://www.asp.net/mvc/tutorials/older-versions/models-%28data%29/validating-with-the-idataerrorinfo-interface-cs moves the individual validation into the properties:
public partial class Player : IDataErrorInfo
{
Dictionary<string, string> _errorInfo;
public Player()
{
_errorInfo = new Dictionary<string, string>();
}
public bool CanSave { get { return _errorInfo.Count == 0; }
public string this[string columnName]
{
get
{
return _errorInfo.ContainsKey(columnName) ? _errorInfo[columnName] : null;
}
}
public string FirstName
{
get { return _firstName;}
set
{
if (String.IsNullOrWhiteSpace(value))
_errorInfo.AddOrUpdate("FirstName", "Geef een voornaam in");
else
{
_errorInfo.Remove("FirstName");
_firstName = value;
}
}
}
}
(you would have to handle the Dictionary AddOrUpdate extension method). This is similar to your error count idea.

I've implemented the map approach shown in my comment above, in C# this is called a Dictionary in which I am using anonymous methods to do the validation:
partial class Player : IDataErrorInfo
{
private delegate string Validation(string value);
private Dictionary<string, Validation> columnValidations;
public List<string> Errors;
public Player()
{
columnValidations = new Dictionary<string, Validation>();
columnValidations["Firstname"] = delegate (string value) {
return String.IsNullOrWhiteSpace(Firstname) ? "Geef een voornaam in" : null;
}; // Add the others...
errors = new List<string>();
}
public bool CanSave { get { return Errors.Count == 0; } }
public string this[string columnName]
{
get { return this.GetProperty(columnName); }
set
{
var error = columnValidations[columnName](value);
if (String.IsNullOrWhiteSpace(error))
errors.Add(error);
else
this.SetProperty(columnName, value);
}
}
}

This approach works with Data Annotations. You can also bind the "IsValid" property to a Save button to enable/disable.
public abstract class ObservableBase : INotifyPropertyChanged, IDataErrorInfo
{
#region Members
private readonly Dictionary<string, string> errors = new Dictionary<string, string>();
#endregion
#region Events
/// <summary>
/// Property Changed Event
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
#endregion
#region Protected Methods
/// <summary>
/// Get the string name for the property
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression"></param>
/// <returns></returns>
protected string GetPropertyName<T>(Expression<Func<T>> expression)
{
var memberExpression = (MemberExpression) expression.Body;
return memberExpression.Member.Name;
}
/// <summary>
/// Notify Property Changed (Shorted method name)
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression"></param>
protected virtual void Notify<T>(Expression<Func<T>> expression)
{
string propertyName = this.GetPropertyName(expression);
PropertyChangedEventHandler handler = this.PropertyChanged;
handler?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
/// <summary>
/// Called when [property changed].
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression">The expression.</param>
protected virtual void OnPropertyChanged<T>(Expression<Func<T>> expression)
{
string propertyName = this.GetPropertyName(expression);
PropertyChangedEventHandler handler = this.PropertyChanged;
handler?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
#region Properties
/// <summary>
/// Gets an error message indicating what is wrong with this object.
/// </summary>
public string Error => null;
/// <summary>
/// Returns true if ... is valid.
/// </summary>
/// <value>
/// <c>true</c> if this instance is valid; otherwise, <c>false</c>.
/// </value>
public bool IsValid => this.errors.Count == 0;
#endregion
#region Indexer
/// <summary>
/// Gets the <see cref="System.String"/> with the specified column name.
/// </summary>
/// <value>
/// The <see cref="System.String"/>.
/// </value>
/// <param name="columnName">Name of the column.</param>
/// <returns></returns>
public string this[string columnName]
{
get
{
var validationResults = new List<ValidationResult>();
string error = null;
if (Validator.TryValidateProperty(GetType().GetProperty(columnName).GetValue(this), new ValidationContext(this) { MemberName = columnName }, validationResults))
{
this.errors.Remove(columnName);
}
else
{
error = validationResults.First().ErrorMessage;
if (this.errors.ContainsKey(columnName))
{
this.errors[columnName] = error;
}
else
{
this.errors.Add(columnName, error);
}
}
this.OnPropertyChanged(() => this.IsValid);
return error;
}
}
#endregion
}