Added helper method to generate expression input which handles 'Not' …

…case

DynamicExpressionBuilder/Enums/QueryOperand.cs

@@ -14,6 +14,11 @@ public enum QueryOperand
         /// <summary>
         /// Equiavlent to ||
         /// </summary>
-        Or
+        Or,
+
+        /// <summary>
+        /// Not should be equivalent to &amp;&amp; but operation should be use Operation.NotEquals
+        /// </summary>
+        Not
     }
 }

DynamicExpressionBuilder/Helpers/ExpressionBuilderHelpers.cs

@@ -0,0 +1,33 @@
+using DynamicExpressionBuilder.Enums;
+using DynamicExpressionBuilder.Models;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace DynamicExpressionBuilder.Helpers
+{
+
+    /// <summary>
+    /// Contains helper methods
+    /// </summary>
+    public class ExpressionBuilderHelpers
+    {
+
+        /// <summary>
+        /// Prepare ExpressionInput object. You can build your own logic to create ExpressionInput object.
+        /// </summary>
+        /// <param name="propertyName">Property Name</param>
+        /// <param name="operation">Operation. Eg. .StartsWith(""), .Contains("")</param>
+        /// <param name="value">Value to operate with</param>
+        /// <param name="operand">Operand. And, Or, Not</param>
+        /// <returns></returns>
+        public static ExpressionInput GetExpressionInput(string propertyName, Operation operation, object value, QueryOperand operand)
+        {
+            if (operand == QueryOperand.Not)
+                return new ExpressionInput { Value = value, Operand = QueryOperand.And, Operation = Operation.NotEquals, PropertyName = propertyName };
+            else
+                return new ExpressionInput { Value = value, Operand = operand, Operation = operation, PropertyName = propertyName };
+
+        }
+    }
+}