using System;

using System.Linq;

using System.Collections.Generic;                   

using System.Collections;                   

using System.Xml;                   

using System.Xml.Linq;

using System.Data;

using System.Data.DataSetExtensions;

using System.Data.Linq;

​

public class Program

{

    public static void Main()

    {

        string input = @"<Root><ROW QUALIFYPREFIX=""PayerAddressChildItem_R1_"" PKEY=""2128465"">

<COL NAME=""IsDefault"" TYPE=""FieldTypeBoolean"" HIDDEN=""1"" OVALUE=""0"" VALUE=""0"" DVALUE=""No"" />

<COL NAME=""AddressType"" TYPE=""FieldTypeValidValues"" OVALUE=""Billing"" VALUE=""Billing"" DVALUE=""Billing"" />

<COL NAME=""AddressLine1"" TYPE=""FieldTypeVarchar"" OVALUE=""111 sts"" VALUE=""111 sts"" DVALUE=""111 sts"" />

<COL NAME=""AddressLine2"" TYPE=""FieldTypeVarchar"" OVALUE="""" VALUE="""" DVALUE="""" />

<COL NAME=""City"" TYPE=""FieldTypeVarchar"" OVALUE=""new york"" VALUE=""new york"" DVALUE=""new york"" />

<COL NAME=""State"" TYPE=""FieldTypeState"" OVALUE=""NC"" VALUE=""NC"" DVALUE=""NC"" />

<COL NAME=""Zip"" TYPE=""FieldTypeZipCode"" OVALUE=""10010"" VALUE=""10010"" DVALUE=""10010"" />

<COL NAME=""BasedOn"" TYPE=""FieldTypeValidValues"" OVALUE=""Billed Date"" VALUE=""Billed Date"" DVALUE=""Billed Date"" />

<COL NAME=""EffectiveDate"" TYPE=""FieldTypeDate"" OVALUE=""4/22/2016 12:00:00 AM"" VALUE=""4/22/2016"" DVALUE=""4/22/2016"" />

<COL NAME=""ExpirationDate"" TYPE=""FieldTypeDate"" OVALUE="""" VALUE="""" DVALUE="""" />

</ROW>

​

<ROW QUALIFYPREFIX=""PayerAddressChildItem_R2_"" REQUEST=""WRITE"">

<COL NAME=""IsDefault"" TYPE=""FieldTypeBoolean"" HIDDEN=""1"" OVALUE="""" VALUE="""" DVALUE=""Unknown"" />

<COL NAME=""AddressType"" TYPE=""FieldTypeValidValues"" OVALUE="""" VALUE=""Billing"" DVALUE=""Billing"" />

<COL NAME=""AddressLine1"" TYPE=""FieldTypeVarchar"" OVALUE="""" VALUE=""111 sts"" DVALUE=""111 sts"" />

<COL NAME=""AddressLine2"" TYPE=""FieldTypeVarchar"" OVALUE="""" VALUE="""" DVALUE="""" />

<COL NAME=""City"" TYPE=""FieldTypeVarchar"" OVALUE="""" VALUE=""new york"" DVALUE=""new york"" />

<COL NAME=""State"" TYPE=""FieldTypeState"" OVALUE="""" VALUE=""AE"" DVALUE=""AE"" />

<COL NAME=""Zip"" TYPE=""FieldTypeZipCode"" OVALUE="""" VALUE=""10010"" DVALUE=""10010"" />

<COL NAME=""BasedOn"" TYPE=""FieldTypeValidValues"" OVALUE="""" VALUE=""Billed Date"" DVALUE=""Billed Date"" />

<COL NAME=""EffectiveDate"" TYPE=""FieldTypeDate"" OVALUE="""" VALUE=""4/23/2016"" DVALUE=""4/23/2016"" />

<COL NAME=""ExpirationDate"" TYPE=""FieldTypeDate"" OVALUE="""" VALUE="""" DVALUE="""" />

</ROW></Root>";

    XDocument root = XDocument.Parse(input);

    var results = root

        .Descendants("COL")

        .Where(x=>x.Attribute("NAME").Value == "EffectiveDate")

        .Select(x=>x.Attribute("VALUE").Value);

        foreach(var result in results)

        {

            Console.WriteLine(result);

        }

​

​

    }

}