feature: Optimize MySql objects lists to use Contains functions as O(1)

- Remove unused imports
- Optmize Lists in MySqlObjects to use Dictionary instead of Lists to optimize Contains function
- Replaces empty strings to use string.Empty to allocate less memory
- Fix the event GetTotalRowsProgressChanged to be called asynchronous using Timer
- Fix ReportEndProcess call to be called when some exception occurs

Author: hmoraes

source code/MySqlBackup(Devart-Express)/EventArgs/ExportProgressArgs.cs

@@ -1,12 +1,10 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 
 namespace Devart.Data.MySql
 {
     public class ExportProgressArgs : EventArgs
     {
-        string _currentTableName = "";
+        string _currentTableName = string.Empty;
         long _totalRowsInCurrentTable = 0;
         long _totalRowsInAllTables = 0;
         long _currentRowIndexInCurrentTable = 0;

source code/MySqlBackup(Devart-Express)/EventArgs/GetTotalRowsArgs.cs

@@ -1,18 +1,16 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 
 namespace Devart.Data.MySql
 {
     public class GetTotalRowsArgs : EventArgs
     {
-        int _totalTables = 0;
-        int _curTable = 0;
-
         public GetTotalRowsArgs(int totalTables, int curTable)
         {
-            _totalTables = totalTables;
-            _curTable = curTable;
+            TotalTables = totalTables;
+            CurrTable = curTable;
         }
+
+        public int TotalTables { get; private set; }
+        public int CurrTable { get; private set; }
     }
 }

source code/MySqlBackup(Devart-Express)/InfoObjects/ImportInformations.cs

@@ -1,14 +1,10 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-
-namespace Devart.Data.MySql
+namespace Devart.Data.MySql
 {
     public class ImportInformations
     {
         int _interval = 100;
-        //string _targetDatabase = "";
-        //string _databaseDefaultCharSet = "";
+        //string _targetDatabase = string.Empty;
+        //string _databaseDefaultCharSet = string.Empty;
 
         /// <summary>
         /// Gets or Sets a value indicates whether the Imported Dump File is encrypted.
@@ -20,7 +16,7 @@ public class ImportInformations
         /// Sets the password used to decrypt the exported dump file.
         /// </summary>
         //[System.Obsolete("This implementation will slow down the whole process which is not recommended. Encrypt the content externally after the export process completed. For more information, please read documentation.")]
-        //public string EncryptionPassword = "";
+        //public string EncryptionPassword = string.Empty;
 
         /// <summary>
         /// Gets or Sets a value indicates the interval of time (in miliseconds) to raise the event of ExportProgressChanged.
@@ -45,7 +41,7 @@ public class ImportInformations
         /// <summary>
         /// Gets or Sets the file path used to log error messages.
         /// </summary>
-        public string ErrorLogFile = "";
+        public string ErrorLogFile = string.Empty;
 
         public ImportInformations()
         { }

source code/MySqlBackup(Devart-Express)/Methods/QueryExpress.cs

@@ -1,9 +1,8 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 using System.Data;
 using System.Globalization;
 using System.Security.Cryptography;
+using System.Text;
 
 namespace Devart.Data.MySql
 {
@@ -403,4 +402,4 @@ public static string ConvertToSqlFormat(object ob, bool wrapStringWithSingleQuot
         }
 
     }
-}
+}