return the difference from a dictionary

Question

I'm trying to compare the values of my dictionary and display my results like this.

Field Values Mismatch For Field: Expected:001 Actual:002

Field Values Mismatch For Field: Expected:003 Actual:002

I'm able to get the difference for each of the rows in my dictionary but I'm not sure how to display my result in string list.

This is what I have try

public static string ValidateMvpFields(string value1, Dictionary<string, ValueMap> value2)
        {
            var xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(value1);

            foreach (var item in value2.Keys)
            {
                try
                {
                    var Val1 = xmlDoc.SelectSingleNode(responseParameters[item].XPath).InnerText;
                    var Val2 = responseParameters[item].Value;
                    if (!Val1.Trim().Equals(Val2.Trim()))
                    {
                        var results = ErrorMessage = $"Mvp Field Values Mismatch For Field: {item} Expected:{Val1} Actual:{Val2}";
                        string result = null;
                        result += String.Join(Environment.NewLine, results);
                    }
                    continue;

                }
                catch (Exception ex)
                {
                    var results = ErrorMessage = $"Invalid Xpath: {value2[item].XPath} For Field:{item} Error:{ex.Message}";
                    /*return results*/
                    ;

                }
            }

            return "";


        }

Here is an example of my dictionary

public static Dictionary<string, ValueMap> Example = new Dictionary<string, ValueMap>
                  {
                    {"Example1", new ValueMap { XPath = "", Value = "5123"} },
                    {"Example2", new ValueMap { XPath ="", Value = "123"} },
}

Answer 1

Instead of initializing string result = null inside for loop, Initialize StringBuilder outside of for loop and append each result to it.

Initialization of string result = null everytime is creating new string variable every time and you are unable to get previously stored result while iterating inside for loop.

public static string ValidateMvpFields(string value1, Dictionary<string, ValueMap> value2)
    {
        var xmlDoc = new XmlDocument();
        xmlDoc.LoadXml(value1);
        StringBuilder sb = new StringBuilder();  //Initialize StringBuider

        foreach (var item in value2.Keys)
        {
            try
            {
                var Val1 = xmlDoc.SelectSingleNode(responseParameters[item].XPath).InnerText;
                var Val2 = responseParameters[item].Value;
                if (!Val1.Trim().Equals(Val2.Trim()))
                {
                    var results = ErrorMessage = $"Mvp Field Values Mismatch For Field: {item} Expected:{Val1} Actual:{Val2}";
                    //Append new value every time into string builder
                    sb.Append(Environment.NewLine);
                    sb.Append(results);
                }
                continue;

            }
            catch (Exception ex)
            {
                var results = ErrorMessage = $"Invalid Xpath: {value2[item].XPath} For Field:{item} Error:{ex.Message}";
                /*return results*/
                ;

            }
        }

        return "";
    }

string type is immutable, when ever you assign new value to string it creates new object, StringBuilder is immutable so it helps to avoid memory leak.

If you want to store result in a list then use List<string> and add new result every time, like

   List<string> results = new List<string>(); //Initialize list
   ……
   results.Add(result);  //Add new value to it