Creating a custom ordered dictionary

Question

I am having trouble with this class. I am converting from VB6 VB.NET to C#.

In particular the Item, AddBefore and AddAfter methods. For the Item I am passing in a geometry shape.

I need to use Ordered Dictionary because I need a format of m_oCol(string, clsFeature). In this collection, I need to insert clsFeatures in a certain order, could be 1, 6, 3, 4, 5, 2 because of processing rules. I have another class that accesses this class.

// ************************** Ordered Dictionary  ****************
    // https://stackoverflow.com/questions/2722767/c-sharp-order-preserving-data-structures
    // http://www.go4expert.com/articles/understanding-c-sharp-dictionaries-t30034/

    public OrderedDictionary m_oCol;
    public Dictionary<string, string> m_oColReverse;

    public clsFeatureCollection()
        : base()
    {
        m_oCol = new OrderedDictionary();
        m_oColReverse = new Dictionary<string, string>();
    }

    public IEnumerator GetEnumerator()
    {
        return m_oCol.GetEnumerator();
    }

    public void Add(IFeature pFeature, string strBefore = "", string strAfter = "", bool bReverse = false)
    {
        if (bReverse == true)
        {
            m_oColReverse.Add(pFeature.OID.ToString().Trim(), pFeature.OID.ToString().Trim());
        }

        if (!ContainsItem(pFeature.OID))
        {
            m_oCol.Add(pFeature.OID.ToString(), pFeature.ShapeCopy);
        }
    }

    public void AddBefore(IFeature pFeature, string strBefore, bool bReverse = false)
    {
        if (bReverse == true)
        {
            m_oColReverse.Add(pFeature.OID.ToString().Trim(), pFeature.OID.ToString().Trim());
        }

        if (!ContainsItem(pFeature.OID))
        {
            if (strBefore != null)
            {
                int intStringBefore = Int32.Parse(strBefore);

                int index = m_oCol.FindIndex(a => a.OID == intStringBefore);

                if (index > 0)
                {
                    m_oCol.Insert(index - 1, pFeature.OID.ToString(), pFeature.ShapeCopy);
                }
                else
                {
                    m_oCol.Insert(0, pFeature.OID.ToString(), pFeature.ShapeCopy);
                }
            }
        }
    }

    public void AddAfter(IFeature pFeature, string strAfter, bool bReverse = false)
    {
        if (bReverse == true)
        {
            m_oColReverse.Add(pFeature.OID.ToString().Trim(), pFeature.OID.ToString().Trim());
        }

        if (!ContainsItem(pFeature.OID))
        {
            if (!string.IsNullOrEmpty(strAfter))
            {
                int intStringAfter = Int32.Parse(strAfter);

                int index = m_oCol.FindIndex(a => a.OID == intStringAfter);

                m_oCol.Insert(index + 1, pFeature.OID.ToString(), pFeature.ShapeCopy);
            }
            else
            {
                m_oCol.Add(pFeature.OID.ToString(), pFeature.ShapeCopy);
            }
        }
    }

    public int Count
    {
        get { return m_oCol.Count; }
    }

    public void Remove(int Id)
    {
        m_oCol.RemoveAt(Id);
    }

//        public clsFeature this[int Position]
//        {
//            get { return m_oCol[Position]; }
//            set;
//        }

    public clsFeature Item(int Position)
    {
        clsFeature value = default(clsFeature);

        value = m_oCol[Position]; // .GetObjectData(, Position);

        return value;
    }

    public void Clear()
    {
        m_oCol = new OrderedDictionary();
        m_oColReverse = new Dictionary<string, string>();
    }

    public bool Reverse(string valueRenamed)
    {
        bool bReverse = false;

        try
        {
            if (m_oColReverse.ContainsValue(valueRenamed))
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        catch (Exception ex)
        {
            if (ex is ArgumentException | ex is IndexOutOfRangeException)
            {
                bReverse = false;
            }
        }

        return bReverse;
    }

    public bool ContainsItem(int oidValue)
    {
        bool bContainsItem = false;

        int intOID = oidValue;

        try
        {
            // dictionary
            if (m_oCol.Contains(intOID))
            {
                bContainsItem = true;
            }
            else
            {
                bContainsItem = false;
            }

            return bContainsItem;
        }

        catch (Exception ex)
        {
            if (ex is ArgumentException | ex is IndexOutOfRangeException)
            {
                bContainsItem = false;
            }
        }

        return bContainsItem;
    }

@Plutonix Its an old program being converted to C# 4 and some parts are giving me problems.. especially the collections — Deke, Sep 01 '15 at 15:26
@SLaks well for the Item I get a cast error and I am not sure why. It tells me I cant implicitly convert type object to clsFeature. value = (clsFeature)m_oCol[Position]; even though it compiles — Deke, Sep 01 '15 at 15:29

Reza Aghaei · Accepted Answer · 2015-09-01T17:42:01.293

Use System.Collections.Specialized.OrderedDictionary instead

It has an Insert method that takes an index as one of its input. That way you can insert after or before an item you want.

To check existence of a key use Contains method.
To get item by key use indexer syntax with key, for example collection["mykey"]
To get item by index use indexer syntax with index, for example collection[5]

You can write an extension method for IndexOf:

public static class Extensions
{
    public static int IndexOf(this System.Collections.Specialized.OrderedDictionary od, object key)
    {
        for (int index = 0; index < od.Count; index++)
        {
            if (od.Keys.OfType<object>().ToList()[index] == key)
                return index;
        }
        return -1;
    }
}

The above method, returns index of given key in dictionary and if the key not exists in dictionary, it returns -1

Wherever you want to use your extension method, remember to include its namespace to 'using's

And here is the usage:

var dictionary = new System.Collections.Specialized.OrderedDictionary();

dictionary.Add("A", "A Value");
dictionary.Add("C", "C Value");
dictionary.Add("D", "D Value");

MessageBox.Show(dictionary.IndexOf("C").ToString()); //Shoud be 1
MessageBox.Show(dictionary.IndexOf("B").ToString()); //Shoud be -1

dictionary.Insert(1, "B", "B Value");

MessageBox.Show(dictionary.IndexOf("B").ToString()); //Shoud be 1
MessageBox.Show(dictionary.IndexOf("D").ToString()); //Shoud be 3

Creating a custom ordered dictionary

1 Answers1