TextBoxDragDrop.cs

using System;
using System.ComponentModel;
using System.Drawing;
using System.IO;
using System.Text;
using System.Windows.Forms;
using be.gaudry.model;
using be.gaudry.model.config;
using be.gaudry.observer;
 
namespace be.gaudry.view.controls
{
 
    public partial class TextBoxDragDrop : TextBox
    {
        private int lastSelStart = 0;
        private int lastSelLength = 0;
        private bool candidateToDragDrop = false;
 
        public TextBoxDragDrop()
        {
            InitializeComponent();
            init();
        }
 
        public TextBoxDragDrop(IContainer container)
        {
            container.Add(this);
            InitializeComponent();
            init();
        }
 
        private void init()
        {
            this.DragDrop += new System.Windows.Forms.DragEventHandler(this.onTextBox_DragDrop);
            this.DragEnter += new System.Windows.Forms.DragEventHandler(this.onTextBox_DragEnter);
            this.AllowDrop = true;
            SourcesManager.addSource(new Source(
                "drag and drop",
                "TextBoxDragDrop",
                "http://msdn2.microsoft.com/fr-fr/library/system.windows.forms.drageventargs(VS.80).aspx",
                "Gestion des touches pour le drag and drop"
                )
            );
        }
 
 
        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            if (lastSelLength == 0)
            {
                lastSelLength = SelectionLength;
                lastSelStart = SelectionStart;
            }
            else
            {
                lastSelLength = 0;
                lastSelStart = 0;
                candidateToDragDrop = false;
            }
       }
 
        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            //todo test if cursor is over the selected text
            if (lastSelLength > 0)
            {
                candidateToDragDrop = true;
            }
        }
 
        protected override void OnMouseMove(MouseEventArgs e)
        {
            base.OnMouseMove(e);
            //todo : test if cursor is over the selected text
            if (candidateToDragDrop)
            {
                DragDropEffects dr;
                if (lastSelLength == Text.Length)//we may use move of a entire string
                {
                    if (!TextHelper.isKeyDown(TextHelper.KEY.CONTROL))
                    {
                        dr = DoDragDrop(Text, DragDropEffects.Move);
                        if (dr == DragDropEffects.Move)
                            Text = "";
                    }
                    else
                    {
                        DoDragDrop(Text, DragDropEffects.Copy);
                    }
                }
                else
                {
                    //get selected text
                    try
                    {
                        string str = Text.Substring(lastSelStart, lastSelLength);
                        //we may not use DragDropEffects.All or move because we drag only a part of string
                        dr = DoDragDrop(str, DragDropEffects.Copy);
                        //remove selected text to simulate move
                        if (dr == DragDropEffects.Copy && !TextHelper.isKeyDown(TextHelper.KEY.CONTROL))
                        {
                            Text = Text.Remove(lastSelStart, lastSelLength);
                        }
                    }
                    catch (Exception ex)
                    {
                        StaticObservable.notify(new Notification(
                            Notification.VERBOSE.lowError, 
                            string.Format("{0} : {1}",this.GetType().ToString(),this.Name), 
                            "Erreur de drag and drop", 
                            ex, 
                            this
                            ));
                    }
                }
                //reinit
                lastSelLength = 0;
                lastSelStart = 0;
                candidateToDragDrop = false;
            }
        }
 
        /*
        protected override void OnDragEnter(DragEventArgs e)
        {
            base.OnDragEnter(e);
            e.Effect = DragDropEffects.All;
        }
        protected override void OnDragDrop(DragEventArgs e)
        {
            base.OnDragDrop(e);
            if (e.Effect != DragDropEffects.None) //e.Data.GetDataPresent(typeof(string)))
            {
                Text = Text.Insert(
                    SelectionStart,
                    //(string)e.Data.GetData(typeof(string))
                    getDropObjectAsText(e)
                    );
            }
            this.SelectionLength = 0;
            this.SelectionStart = Text.Length;
            this.Focus();
        }
        */
 
        private void onTextBox_DragEnter(object sender, DragEventArgs e)
        {
            //if (e.Data.GetDataPresent(typeof(string)))
            //{
                //e.Effect = DragDropEffects.Copy;
            //}
            //e.Effect = DragDropEffects.All;
 
            if ((e.KeyState & 4) == 4 &&
                (e.AllowedEffect & DragDropEffects.Move) == DragDropEffects.Move)
            {
                // SHIFT KeyState for move.
                e.Effect = DragDropEffects.Move;
            }
            else if ((e.KeyState & 8) == 8 &&
                (e.AllowedEffect & DragDropEffects.Copy) == DragDropEffects.Copy)
            {
                // CTL KeyState for copy.
                e.Effect = DragDropEffects.Copy;
            }
            else if ((e.AllowedEffect & DragDropEffects.Move) == DragDropEffects.Move)
            {
                // By default, the drop action should be move, if allowed.
                e.Effect = DragDropEffects.Move;
            }
            else if ((e.AllowedEffect & DragDropEffects.Copy) == DragDropEffects.Copy)
            {
                e.Effect = DragDropEffects.Copy;
            }
            else
                e.Effect = DragDropEffects.None;
        }
 
        private void onTextBox_DragDrop(object sender, DragEventArgs e)
        {
            //allow drop for other types (file, etc)
            if (e.Effect!= DragDropEffects.None) //e.Data.GetDataPresent(typeof(string)))
            {
                Text = Text.Insert(
                    SelectionStart, 
                    //(string)e.Data.GetData(typeof(string))
                    getDropObjectAsText(e)
                    );
                this.SelectionLength = 0;
                this.SelectionStart = Text.Length;
                this.Focus();
            }
        }
 
        protected override void OnDragOver(DragEventArgs e)
        {
            base.OnDragOver(e);
            //get insertion point
            Point pt = this.PointToClient(new Point(e.X, e.Y));
            SelectionStart = TextHelper.CharFromPos(this, pt);
        }
 
        /*private void setEffect(DragEventArgs e)
        {
            if((e.KeyState & 4) == 4 &&
              (e.AllowedEffect & DragDropEffects.Move) == DragDropEffects.Move)
            {
 
                // SHIFT KeyState for move.
                e.Effect = DragDropEffects.Move;
 
            }
                
            else if ((e.KeyState & 8) == 8 &&
              (e.AllowedEffect & DragDropEffects.Copy) == DragDropEffects.Copy)
            {
 
                // CTL KeyState for copy.
                e.Effect = DragDropEffects.Copy;
 
            }
            else
                e.Effect = DragDropEffects.None;
            
        }*/
 
        protected virtual string getDropObjectAsText(DragEventArgs e)
        {
            if (e.Data.GetDataPresent(typeof(string)))
            {
                return (string)e.Data.GetData(typeof(string));
            }
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                string[] DropFiles = (string[])e.Data.GetData(DataFormats.FileDrop);
                StringBuilder str = new StringBuilder();
                foreach (string s in DropFiles)
                {
                    if (str.Length > 0)
                        str.Append(", ");
                    str.Append(Path.GetFileNameWithoutExtension(s));
                }
                return str.ToString();
            }
            //MessageBox.Show("Impossible de déposer l'élément ici");
            e.Effect = DragDropEffects.None;
            return "";
        }
 
    }
}