AmalgamationTool/DynamORM.Amalgamation.cs

@@ -48,12 +48,14 @@ using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.Serialization;
 using System.Text;
+using System.Text.RegularExpressions;
 using DynamORM.Builders;
 using DynamORM.Builders.Extensions;
 using DynamORM.Builders.Implementation;
 using DynamORM.Helpers;
 using DynamORM.Helpers.Dynamics;
 using DynamORM.Mapper;
+using DynamORM.Validation;
 
 [module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1402:FileMayOnlyContainASingleClass", Justification = "This is a generated file which generates all the necessary support classes.")]
 [module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1403:FileMayOnlyContainASingleNamespace", Justification = "This is a generated file which generates all the necessary support classes.")]
@@ -2857,6 +2859,7 @@ namespace DynamORM
                 {
                     case "varchar":
                         return DbType.AnsiString;
+
                     case "nvarchar":
                         return DbType.String;
                 }
@@ -5066,7 +5069,7 @@ namespace DynamORM
             return defaultValue;
         }
 
-        /// <summary>Delegate fro try parse function of a type.</summary>
+        /// <summary>Delegate from try parse function of a type.</summary>
         /// <typeparam name="T">Type which implements this function.</typeparam>
         /// <param name="value">Value to parse.</param>
         /// <param name="result">Resulting value.</param>
@@ -6510,7 +6513,7 @@ namespace DynamORM
     namespace Builders
     {
         /// <summary>Dynamic delete query builder interface.</summary>
-        /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+        /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
         public interface IDynamicDeleteQueryBuilder : IDynamicQueryBuilder
         {
             /// <summary>Execute this builder.</summary>
@@ -6556,7 +6559,7 @@ namespace DynamORM
         }
 
         /// <summary>Dynamic insert query builder interface.</summary>
-        /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+        /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
         public interface IDynamicInsertQueryBuilder : IDynamicQueryBuilder
         {
             /// <summary>Execute this builder.</summary>
@@ -6587,7 +6590,7 @@ namespace DynamORM
         }
 
         /// <summary>Dynamic query builder base interface.</summary>
-        /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+        /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
         public interface IDynamicQueryBuilder : IExtendedDisposable
         {
             /// <summary>Gets <see cref="DynamicDatabase"/> instance.</summary>
@@ -6627,7 +6630,7 @@ namespace DynamORM
         }
 
         /// <summary>Dynamic select query builder interface.</summary>
-        /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+        /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
         public interface IDynamicSelectQueryBuilder : IDynamicQueryBuilder ////, IEnumerable<object>
         {
             /// <summary>Execute this builder.</summary>
@@ -6881,7 +6884,7 @@ namespace DynamORM
         }
 
         /// <summary>Dynamic update query builder interface.</summary>
-        /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+        /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
         public interface IDynamicUpdateQueryBuilder : IDynamicQueryBuilder
         {
             /// <summary>Execute this builder.</summary>
@@ -12420,8 +12423,16 @@ namespace DynamORM
                             throw new ArgumentException(string.Format("Argument '{0}' must be dynamic.", p.Name));
                     }
 
+                    try
+                    {
                         _uncertainResult = f.DynamicInvoke(_arguments.ToArray());
                     }
+                    catch (TargetInvocationException e)
+                    {
+                        if (e.InnerException != null) throw e.InnerException;
+                        else throw e;
+                    }
+                }
 
                 /// <summary>
                 /// Parses the dynamic lambda expression given in the form of a delegate, and returns a new instance of the
@@ -13097,8 +13108,11 @@ namespace DynamORM
                 public int Ordinal { get; set; }
             }
 
-            private Type _arrayType;
-            private bool _genericEnumerable;
+            /// <summary>Gets the array type of property if main type is a form of collection.</summary>
+            public Type ArrayType { get; private set; }
+
+            /// <summary>Gets a value indicating whether this property is in fact a generic list.</summary>
+            public bool IsGnericEnumerable { get; private set; }
 
             /// <summary>Gets the type of property.</summary>
             public Type Type { get; private set; }
@@ -13115,6 +13129,9 @@ namespace DynamORM
             /// <summary>Gets type column description.</summary>
             public ColumnAttribute Column { get; private set; }
 
+            /// <summary>Gets type list of property requirements.</summary>
+            public List<RequiredAttribute> Requirements { get; private set; }
+
             /// <summary>Gets a value indicating whether this <see cref="DynamicPropertyInvoker"/> is ignored in some cases.</summary>
             public bool Ignore { get; private set; }
 
@@ -13130,21 +13147,22 @@ namespace DynamORM
                 Type = property.PropertyType;
 
                 object[] ignore = property.GetCustomAttributes(typeof(IgnoreAttribute), false);
+                Requirements = property.GetCustomAttributes(typeof(RequiredAttribute), false).Cast<RequiredAttribute>().ToList();
 
                 Ignore = ignore != null && ignore.Length > 0;
 
-                _arrayType = Type.IsArray ? Type.GetElementType() :
-                    Type.IsGenericEnumerable() ? Type.GetGenericArguments().First() :
+                IsGnericEnumerable = Type.IsGenericEnumerable();
+
+                ArrayType = Type.IsArray ? Type.GetElementType() :
+                    IsGnericEnumerable ? Type.GetGenericArguments().First() :
                     Type;
 
-                _genericEnumerable = Type.IsGenericEnumerable();
+                IsDataContract = ArrayType.GetCustomAttributes(false).Any(x => x.GetType().Name == "DataContractAttribute");
 
-                IsDataContract = _arrayType.GetCustomAttributes(false).Any(x => x.GetType().Name == "DataContractAttribute");
-
-                if (_arrayType.IsArray)
+                if (ArrayType.IsArray)
                     throw new InvalidOperationException("Jagged arrays are not supported");
 
-                if (_arrayType.IsGenericEnumerable())
+                if (ArrayType.IsGenericEnumerable())
                     throw new InvalidOperationException("Enumerables of enumerables are not supported");
 
                 Column = attr;
@@ -13199,20 +13217,20 @@ namespace DynamORM
                 {
                     if (!Type.IsAssignableFrom(val.GetType()))
                     {
-                        if (Type.IsArray || _genericEnumerable)
+                        if (Type.IsArray || IsGnericEnumerable)
                         {
                             if (val != null)
                             {
-                                var lst = (val as IEnumerable<object>).Select(x => GetElementVal(_arrayType, x)).ToList();
+                                var lst = (val as IEnumerable<object>).Select(x => GetElementVal(ArrayType, x)).ToList();
 
-                                value = Array.CreateInstance(_arrayType, lst.Count);
+                                value = Array.CreateInstance(ArrayType, lst.Count);
 
                                 int i = 0;
                                 foreach (var e in lst)
                                     ((Array)value).SetValue(e, i++);
                             }
                             else
-                                value = Array.CreateInstance(_arrayType, 0);
+                                value = Array.CreateInstance(ArrayType, 0);
                         }
                         else
                             value = GetElementVal(Type, val);
@@ -13248,7 +13266,17 @@ namespace DynamORM
                 else if (type.IsEnum && val.GetType().IsValueType)
                     return Enum.ToObject(type, val);
                 else if (type.IsEnum)
+                    try
+                    {
                         return Enum.Parse(type, val.ToString());
+                    }
+                    catch (ArgumentException)
+                    {
+                        if (nullable)
+                            return null;
+
+                        throw;
+                    }
                 else if (Type == typeof(string) && val.GetType() == typeof(Guid))
                     return val.ToString();
                 else if (Type == typeof(Guid) && val.GetType() == typeof(string))
@@ -13259,8 +13287,18 @@ namespace DynamORM
                 else if (IsDataContract)
                     return val.Map(type);
                 else
+                    try
+                    {
                         return Convert.ChangeType(val, type);
                     }
+                    catch
+                    {
+                        if (nullable)
+                            return null;
+
+                        throw;
+                    }
+            }
 
             #region Type command cache
 
@@ -13377,6 +13415,57 @@ namespace DynamORM
                 return destination;
             }
 
+            /// <summary>Validates the object.</summary>
+            /// <param name="val">The value.</param>
+            /// <returns>List of not valid results.</returns>
+            public IList<ValidationResult> ValidateObject(object val)
+            {
+                var result = new List<ValidationResult>();
+
+                if (val == null || val.GetType() != Type)
+                    return null;
+
+                foreach (var prop in ColumnsMap.Values)
+                {
+                    if (prop.Requirements == null || !prop.Requirements.Any())
+                        continue;
+
+                    var v = prop.Get(val);
+
+                    foreach (var r in prop.Requirements)
+                    {
+                        var valid = r.ValidateSimpleValue(prop, v);
+
+                        if (valid == ValidateResult.Valid)
+                        {
+                            if (prop.Type.IsArray || prop.IsGnericEnumerable)
+                            {
+                                var map = DynamicMapperCache.GetMapper(prop.ArrayType);
+                                foreach (var item in val as IEnumerable<object>)
+                                    result.AddRange(map.ValidateObject(item));
+                            }
+
+                            continue;
+                        }
+
+                        if (valid == ValidateResult.NotSupported)
+                        {
+                            result.AddRange(DynamicMapperCache.GetMapper(prop.Type).ValidateObject(v));
+                            continue;
+                        }
+
+                        result.Add(new ValidationResult()
+                        {
+                            Property = prop,
+                            Requirement = r,
+                            Value = v,
+                        });
+                    }
+                }
+
+                return result;
+            }
+
             private IEnumerable<MemberInfo> GetAllMembers(Type type)
             {
                 if (type.IsInterface)
@@ -13451,4 +13540,167 @@ namespace DynamORM
             public bool Override { get; set; }
         }
     }
+
+    namespace Validation
+    {
+        /// <summary>Required attribute can be used to validate fields in objects using mapper class.</summary>
+        [AttributeUsage(AttributeTargets.Property)]
+        public class RequiredAttribute : Attribute
+        {
+            /// <summary>Gets or sets minimum value or length of field.</summary>
+            public decimal? Min { get; set; }
+
+            /// <summary>Gets or sets maximum value or length of field.</summary>
+            public decimal? Max { get; set; }
+
+            /// <summary>Gets or sets pattern to verify.</summary>
+            public Regex Pattern { get; set; }
+
+            /// <summary>Gets or sets a value indicating whether property value is required or not.</summary>
+            public bool Required { get; set; }
+
+            /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+            /// <param name="required">This field will be required.</param>
+            public RequiredAttribute(bool required = true)
+            {
+                Required = required;
+            }
+
+            /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+            /// <param name="val">Limiting value to set.</param>
+            /// <param name="max">Whether set maximum parameter (true) or minimum parameter (false).</param>
+            /// <param name="required">This field will be required.</param>
+            public RequiredAttribute(float val, bool max, bool required = true)
+            {
+                if (max)
+                    Max = (decimal)val;
+                else
+                    Min = (decimal)val;
+                Required = required;
+            }
+
+            /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+            /// <param name="min">Minimum value to set.</param>
+            /// <param name="max">Maximum value to set.</param>
+            /// <param name="required">This field will be required.</param>
+            public RequiredAttribute(float min, float max, bool required = true)
+            {
+                Min = (decimal)min;
+                Max = (decimal)max;
+                Required = required;
+            }
+
+            /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+            /// <param name="min">Minimum value to set.</param>
+            /// <param name="max">Maximum value to set.</param>
+            /// <param name="pattern">Pattern to check.</param>
+            /// <param name="required">This field will be required.</param>
+            public RequiredAttribute(float min, float max, string pattern, bool required = true)
+            {
+                Min = (decimal)min;
+                Max = (decimal)max;
+                Pattern = new Regex(pattern, RegexOptions.Compiled);
+                Required = required;
+            }
+
+            internal ValidateResult ValidateSimpleValue(DynamicPropertyInvoker dpi, object val)
+            {
+                if (val == null && Required)
+                    return ValidateResult.ValueIsMissing;
+
+                if (dpi.Type.IsValueType)
+                {
+                    if (val is decimal || val is long || val is int || val is float || val is double || val is short || val is byte ||
+                        val is decimal? || val is long? || val is int? || val is float? || val is double? || val is short? || val is byte?)
+                    {
+                        decimal dec = Convert.ToDecimal(val);
+
+                        if (Min.HasValue && Min.Value > dec)
+                            return ValidateResult.ValueTooSmall;
+
+                        if (Max.HasValue && Max.Value < dec)
+                            return ValidateResult.ValueTooLarge;
+
+                        return ValidateResult.Valid;
+                    }
+                    else
+                    {
+                        var str = val.ToString();
+
+                        if (Min.HasValue && Min.Value > str.Length)
+                            return ValidateResult.ValueTooShort;
+
+                        if (Max.HasValue && Max.Value < str.Length)
+                            return ValidateResult.ValueTooLong;
+
+                        if (Pattern != null && !Pattern.IsMatch(str))
+                            return ValidateResult.ValueDontMatchPattern;
+
+                        return ValidateResult.Valid;
+                    }
+                }
+                else if (dpi.Type.IsArray || dpi.IsGnericEnumerable)
+                {
+                    var cnt = (val as IEnumerable<object>).Count();
+
+                    if (Min.HasValue && Min.Value > cnt)
+                        return ValidateResult.TooFewElementsInCollection;
+
+                    if (Max.HasValue && Max.Value < cnt)
+                        return ValidateResult.TooManyElementsInCollection;
+
+                    return ValidateResult.Valid;
+                }
+
+                return ValidateResult.NotSupported;
+            }
+        }
+
+        /// <summary>Validation result enum.</summary>
+        public enum ValidateResult
+        {
+            /// <summary>The valid value.</summary>
+            Valid,
+
+            /// <summary>The value is missing.</summary>
+            ValueIsMissing,
+
+            /// <summary>The value too small.</summary>
+            ValueTooSmall,
+
+            /// <summary>The value too large.</summary>
+            ValueTooLarge,
+
+            /// <summary>The too few elements in collection.</summary>
+            TooFewElementsInCollection,
+
+            /// <summary>The too many elements in collection.</summary>
+            TooManyElementsInCollection,
+
+            /// <summary>The value too short.</summary>
+            ValueTooShort,
+
+            /// <summary>The value too long.</summary>
+            ValueTooLong,
+
+            /// <summary>The value don't match pattern.</summary>
+            ValueDontMatchPattern,
+
+            /// <summary>The not supported.</summary>
+            NotSupported,
+        }
+
+        /// <summary>Validation result.</summary>
+        public class ValidationResult
+        {
+            /// <summary>Gets the property invoker.</summary>
+            public DynamicPropertyInvoker Property { get; internal set; }
+
+            /// <summary>Gets the requirement definition.</summary>
+            public RequiredAttribute Requirement { get; internal set; }
+
+            /// <summary>Gets the value that is broken.</summary>
+            public object Value { get; internal set; }
+        }
+    }
 }

DynamORM/Builders/IDynamicDeleteQueryBuilder.cs

@@ -31,7 +31,7 @@ using System;
 namespace DynamORM.Builders
 {
     /// <summary>Dynamic delete query builder interface.</summary>
-    /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+    /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
     public interface IDynamicDeleteQueryBuilder : IDynamicQueryBuilder
     {
         /// <summary>Execute this builder.</summary>

DynamORM/Builders/IDynamicInsertQueryBuilder.cs

@@ -31,7 +31,7 @@ using System;
 namespace DynamORM.Builders
 {
     /// <summary>Dynamic insert query builder interface.</summary>
-    /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+    /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
     public interface IDynamicInsertQueryBuilder : IDynamicQueryBuilder
     {
         /// <summary>Execute this builder.</summary>

DynamORM/Builders/IDynamicQueryBuilder.cs

@@ -34,7 +34,7 @@ using DynamORM.Helpers;
 namespace DynamORM.Builders
 {
     /// <summary>Dynamic query builder base interface.</summary>
-    /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+    /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
     public interface IDynamicQueryBuilder : IExtendedDisposable
     {
         /// <summary>Gets <see cref="DynamicDatabase"/> instance.</summary>

DynamORM/Builders/IDynamicSelectQueryBuilder.cs

@@ -33,7 +33,7 @@ using System.Data;
 namespace DynamORM.Builders
 {
     /// <summary>Dynamic select query builder interface.</summary>
-    /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+    /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
     public interface IDynamicSelectQueryBuilder : IDynamicQueryBuilder ////, IEnumerable<object>
     {
         /// <summary>Execute this builder.</summary>

DynamORM/Builders/IDynamicUpdateQueryBuilder.cs

@@ -31,7 +31,7 @@ using System;
 namespace DynamORM.Builders
 {
     /// <summary>Dynamic update query builder interface.</summary>
-    /// <remarks>This interface it publically available. Implementation should be hidden.</remarks>
+    /// <remarks>This interface it publicly available. Implementation should be hidden.</remarks>
     public interface IDynamicUpdateQueryBuilder : IDynamicQueryBuilder
     {
         /// <summary>Execute this builder.</summary>

DynamORM/DynamORM.csproj

@@ -104,11 +104,14 @@
     <Compile Include="Mapper\DynamicPropertyInvoker.cs" />
     <Compile Include="Mapper\DynamicTypeMap.cs" />
     <Compile Include="Mapper\IgnoreAttribute.cs" />
+    <Compile Include="Validation\RequiredAttribute.cs" />
     <Compile Include="Mapper\TableAttribute.cs" />
     <Compile Include="Mapper\DynamicCast.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="DynamicExpando.cs" />
     <Compile Include="Helpers\IFinalizerDisposable.cs" />
+    <Compile Include="Validation\ValidateResult.cs" />
+    <Compile Include="Validation\ValidationResult.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 

DynamORM/DynamicDatabase.cs

@@ -1398,6 +1398,7 @@ namespace DynamORM
                 {
                     case "varchar":
                         return DbType.AnsiString;
+
                     case "nvarchar":
                         return DbType.String;
                 }

DynamORM/DynamicExtensions.cs

@@ -1605,7 +1605,7 @@ namespace DynamORM
             return defaultValue;
         }
 
-        /// <summary>Delegate fro try parse function of a type.</summary>
+        /// <summary>Delegate from try parse function of a type.</summary>
         /// <typeparam name="T">Type which implements this function.</typeparam>
         /// <param name="value">Value to parse.</param>
         /// <param name="result">Resulting value.</param>

DynamORM/DynamicTransaction.cs

@@ -27,7 +27,6 @@
 */
 
 using System;
-using System.Collections;
 using System.Collections.Generic;
 using System.Data;
 using System.Linq;

DynamORM/Helpers/Dynamics/DynamicParser.cs

@@ -438,7 +438,6 @@ namespace DynamORM.Helpers.Dynamics
                         catch
                         {
                         }
-
                     }
 
                     base.Dispose(disposing);
@@ -650,7 +649,6 @@ namespace DynamORM.Helpers.Dynamics
                         catch
                         {
                         }
-
                     }
 
                     base.Dispose(disposing);
@@ -839,7 +837,6 @@ namespace DynamORM.Helpers.Dynamics
                     return string.Format("{0}.{1}{2}", Host.Sketch(), Name.Sketch(), Arguments == null ? "()" : Arguments.Sketch(brackets: "()".ToCharArray()));
                 }
 
-
                 /// <summary>Performs application-defined tasks associated with
                 /// freeing, releasing, or resetting unmanaged resources.</summary>
                 /// <param name="disposing">If set to <c>true</c> dispose object.</param>
@@ -875,7 +872,6 @@ namespace DynamORM.Helpers.Dynamics
 
                     base.Dispose(disposing);
                 }
-
             }
 
             #endregion Method

DynamORM/Mapper/DynamicPropertyInvoker.cs

@@ -32,6 +32,7 @@ using System.Data;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
+using DynamORM.Validation;
 
 namespace DynamORM.Mapper
 {
@@ -47,8 +48,11 @@ namespace DynamORM.Mapper
             public int Ordinal { get; set; }
         }
 
-        private Type _arrayType;
-        private bool _genericEnumerable;
+        /// <summary>Gets the array type of property if main type is a form of collection.</summary>
+        public Type ArrayType { get; private set; }
+
+        /// <summary>Gets a value indicating whether this property is in fact a generic list.</summary>
+        public bool IsGnericEnumerable { get; private set; }
 
         /// <summary>Gets the type of property.</summary>
         public Type Type { get; private set; }
@@ -65,6 +69,9 @@ namespace DynamORM.Mapper
         /// <summary>Gets type column description.</summary>
         public ColumnAttribute Column { get; private set; }
 
+        /// <summary>Gets type list of property requirements.</summary>
+        public List<RequiredAttribute> Requirements { get; private set; }
+
         /// <summary>Gets a value indicating whether this <see cref="DynamicPropertyInvoker"/> is ignored in some cases.</summary>
         public bool Ignore { get; private set; }
 
@@ -80,21 +87,22 @@ namespace DynamORM.Mapper
             Type = property.PropertyType;
 
             object[] ignore = property.GetCustomAttributes(typeof(IgnoreAttribute), false);
+            Requirements = property.GetCustomAttributes(typeof(RequiredAttribute), false).Cast<RequiredAttribute>().ToList();
 
             Ignore = ignore != null && ignore.Length > 0;
 
-            _arrayType = Type.IsArray ? Type.GetElementType() :
-                Type.IsGenericEnumerable() ? Type.GetGenericArguments().First() :
+            IsGnericEnumerable = Type.IsGenericEnumerable();
+
+            ArrayType = Type.IsArray ? Type.GetElementType() :
+                IsGnericEnumerable ? Type.GetGenericArguments().First() :
                 Type;
 
-            _genericEnumerable = Type.IsGenericEnumerable();
+            IsDataContract = ArrayType.GetCustomAttributes(false).Any(x => x.GetType().Name == "DataContractAttribute");
 
-            IsDataContract = _arrayType.GetCustomAttributes(false).Any(x => x.GetType().Name == "DataContractAttribute");
-
-            if (_arrayType.IsArray)
+            if (ArrayType.IsArray)
                 throw new InvalidOperationException("Jagged arrays are not supported");
 
-            if (_arrayType.IsGenericEnumerable())
+            if (ArrayType.IsGenericEnumerable())
                 throw new InvalidOperationException("Enumerables of enumerables are not supported");
 
             Column = attr;
@@ -149,20 +157,20 @@ namespace DynamORM.Mapper
             {
                 if (!Type.IsAssignableFrom(val.GetType()))
                 {
-                    if (Type.IsArray || _genericEnumerable)
+                    if (Type.IsArray || IsGnericEnumerable)
                     {
                         if (val != null)
                         {
-                            var lst = (val as IEnumerable<object>).Select(x => GetElementVal(_arrayType, x)).ToList();
+                            var lst = (val as IEnumerable<object>).Select(x => GetElementVal(ArrayType, x)).ToList();
 
-                            value = Array.CreateInstance(_arrayType, lst.Count);
+                            value = Array.CreateInstance(ArrayType, lst.Count);
 
                             int i = 0;
                             foreach (var e in lst)
                                 ((Array)value).SetValue(e, i++);
                         }
                         else
-                            value = Array.CreateInstance(_arrayType, 0);
+                            value = Array.CreateInstance(ArrayType, 0);
                     }
                     else
                         value = GetElementVal(Type, val);
@@ -198,7 +206,17 @@ namespace DynamORM.Mapper
             else if (type.IsEnum && val.GetType().IsValueType)
                 return Enum.ToObject(type, val);
             else if (type.IsEnum)
+                try
+                {
                     return Enum.Parse(type, val.ToString());
+                }
+                catch (ArgumentException)
+                {
+                    if (nullable)
+                        return null;
+
+                    throw;
+                }
             else if (Type == typeof(string) && val.GetType() == typeof(Guid))
                 return val.ToString();
             else if (Type == typeof(Guid) && val.GetType() == typeof(string))
@@ -209,8 +227,18 @@ namespace DynamORM.Mapper
             else if (IsDataContract)
                 return val.Map(type);
             else
+                try
+                {
                     return Convert.ChangeType(val, type);
                 }
+                catch
+                {
+                    if (nullable)
+                        return null;
+
+                    throw;
+                }
+        }
 
         #region Type command cache
 

DynamORM/Mapper/DynamicTypeMap.cs

@@ -31,6 +31,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
+using DynamORM.Validation;
 
 namespace DynamORM.Mapper
 {
@@ -138,6 +139,57 @@ namespace DynamORM.Mapper
             return destination;
         }
 
+        /// <summary>Validates the object.</summary>
+        /// <param name="val">The value.</param>
+        /// <returns>List of not valid results.</returns>
+        public IList<ValidationResult> ValidateObject(object val)
+        {
+            var result = new List<ValidationResult>();
+
+            if (val == null || val.GetType() != Type)
+                return null;
+
+            foreach (var prop in ColumnsMap.Values)
+            {
+                if (prop.Requirements == null || !prop.Requirements.Any())
+                    continue;
+
+                var v = prop.Get(val);
+
+                foreach (var r in prop.Requirements)
+                {
+                    var valid = r.ValidateSimpleValue(prop, v);
+
+                    if (valid == ValidateResult.Valid)
+                    {
+                        if (prop.Type.IsArray || prop.IsGnericEnumerable)
+                        {
+                            var map = DynamicMapperCache.GetMapper(prop.ArrayType);
+                            foreach (var item in val as IEnumerable<object>)
+                                result.AddRange(map.ValidateObject(item));
+                        }
+
+                        continue;
+                    }
+
+                    if (valid == ValidateResult.NotSupported)
+                    {
+                        result.AddRange(DynamicMapperCache.GetMapper(prop.Type).ValidateObject(v));
+                        continue;
+                    }
+
+                    result.Add(new ValidationResult()
+                    {
+                        Property = prop,
+                        Requirement = r,
+                        Value = v,
+                    });
+                }
+            }
+
+            return result;
+        }
+
         private IEnumerable<MemberInfo> GetAllMembers(Type type)
         {
             if (type.IsInterface)

DynamORM/Validation/RequiredAttribute.cs

@@ -0,0 +1,121 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using DynamORM.Mapper;
+
+namespace DynamORM.Validation
+{
+    /// <summary>Required attribute can be used to validate fields in objects using mapper class.</summary>
+    [AttributeUsage(AttributeTargets.Property)]
+    public class RequiredAttribute : Attribute
+    {
+        /// <summary>Gets or sets minimum value or length of field.</summary>
+        public decimal? Min { get; set; }
+
+        /// <summary>Gets or sets maximum value or length of field.</summary>
+        public decimal? Max { get; set; }
+
+        /// <summary>Gets or sets pattern to verify.</summary>
+        public Regex Pattern { get; set; }
+
+        /// <summary>Gets or sets a value indicating whether property value is required or not.</summary>
+        public bool Required { get; set; }
+
+        /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+        /// <param name="required">This field will be required.</param>
+        public RequiredAttribute(bool required = true)
+        {
+            Required = required;
+        }
+
+        /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+        /// <param name="val">Limiting value to set.</param>
+        /// <param name="max">Whether set maximum parameter (true) or minimum parameter (false).</param>
+        /// <param name="required">This field will be required.</param>
+        public RequiredAttribute(float val, bool max, bool required = true)
+        {
+            if (max)
+                Max = (decimal)val;
+            else
+                Min = (decimal)val;
+            Required = required;
+        }
+
+        /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+        /// <param name="min">Minimum value to set.</param>
+        /// <param name="max">Maximum value to set.</param>
+        /// <param name="required">This field will be required.</param>
+        public RequiredAttribute(float min, float max, bool required = true)
+        {
+            Min = (decimal)min;
+            Max = (decimal)max;
+            Required = required;
+        }
+
+        /// <summary>Initializes a new instance of the <see cref="RequiredAttribute" /> class.</summary>
+        /// <param name="min">Minimum value to set.</param>
+        /// <param name="max">Maximum value to set.</param>
+        /// <param name="pattern">Pattern to check.</param>
+        /// <param name="required">This field will be required.</param>
+        public RequiredAttribute(float min, float max, string pattern, bool required = true)
+        {
+            Min = (decimal)min;
+            Max = (decimal)max;
+            Pattern = new Regex(pattern, RegexOptions.Compiled);
+            Required = required;
+        }
+
+        internal ValidateResult ValidateSimpleValue(DynamicPropertyInvoker dpi, object val)
+        {
+            if (val == null && Required)
+                return ValidateResult.ValueIsMissing;
+
+            if (dpi.Type.IsValueType)
+            {
+                if (val is decimal || val is long || val is int || val is float || val is double || val is short || val is byte ||
+                    val is decimal? || val is long? || val is int? || val is float? || val is double? || val is short? || val is byte?)
+                {
+                    decimal dec = Convert.ToDecimal(val);
+
+                    if (Min.HasValue && Min.Value > dec)
+                        return ValidateResult.ValueTooSmall;
+
+                    if (Max.HasValue && Max.Value < dec)
+                        return ValidateResult.ValueTooLarge;
+
+                    return ValidateResult.Valid;
+                }
+                else
+                {
+                    var str = val.ToString();
+
+                    if (Min.HasValue && Min.Value > str.Length)
+                        return ValidateResult.ValueTooShort;
+
+                    if (Max.HasValue && Max.Value < str.Length)
+                        return ValidateResult.ValueTooLong;
+
+                    if (Pattern != null && !Pattern.IsMatch(str))
+                        return ValidateResult.ValueDontMatchPattern;
+
+                    return ValidateResult.Valid;
+                }
+            }
+            else if (dpi.Type.IsArray || dpi.IsGnericEnumerable)
+            {
+                var cnt = (val as IEnumerable<object>).Count();
+
+                if (Min.HasValue && Min.Value > cnt)
+                    return ValidateResult.TooFewElementsInCollection;
+
+                if (Max.HasValue && Max.Value < cnt)
+                    return ValidateResult.TooManyElementsInCollection;
+
+                return ValidateResult.Valid;
+            }
+
+            return ValidateResult.NotSupported;
+        }
+    }
+}

DynamORM/Validation/ValidateResult.cs

@@ -0,0 +1,36 @@
+namespace DynamORM.Validation
+{
+    /// <summary>Validation result enum.</summary>
+    public enum ValidateResult
+    {
+        /// <summary>The valid value.</summary>
+        Valid,
+
+        /// <summary>The value is missing.</summary>
+        ValueIsMissing,
+
+        /// <summary>The value too small.</summary>
+        ValueTooSmall,
+
+        /// <summary>The value too large.</summary>
+        ValueTooLarge,
+
+        /// <summary>The too few elements in collection.</summary>
+        TooFewElementsInCollection,
+
+        /// <summary>The too many elements in collection.</summary>
+        TooManyElementsInCollection,
+
+        /// <summary>The value too short.</summary>
+        ValueTooShort,
+
+        /// <summary>The value too long.</summary>
+        ValueTooLong,
+
+        /// <summary>The value don't match pattern.</summary>
+        ValueDontMatchPattern,
+
+        /// <summary>The not supported.</summary>
+        NotSupported,
+    }
+}

DynamORM/Validation/ValidationResult.cs

@@ -0,0 +1,17 @@
+using DynamORM.Mapper;
+
+namespace DynamORM.Validation
+{
+    /// <summary>Validation result.</summary>
+    public class ValidationResult
+    {
+        /// <summary>Gets the property invoker.</summary>
+        public DynamicPropertyInvoker Property { get; internal set; }
+
+        /// <summary>Gets the requirement definition.</summary>
+        public RequiredAttribute Requirement { get; internal set; }
+
+        /// <summary>Gets the value that is broken.</summary>
+        public object Value { get; internal set; }
+    }
+}

Settings.StyleCop

@@ -0,0 +1,234 @@
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