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c#winformsdrag-and-droprichtextbox

Remove icon automatically by dropped file on RichTextBox


I set to true the AllowDrop implemented the DragOver and DragDrop events RichTextBox. On DragDrop event I load the dropped text files' contents on the RTB but it does add the icon of the file in RTB I'd to remove it:

enter image description here

Edit: Here's my code:

void msg_setup_dragDrop()
        {
            msg_textBox.AllowDrop = true;

msg_textBox.EnableAutoDragDrop = true; msg_textBox.DragEnter += new DragEventHandler(msg_DragEnter); msg_textBox.DragDrop += new DragEventHandler(msg_DragDrop); }

        void msg_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
                e.Effect = DragDropEffects.Copy;
        }

        void msg_DragDrop(object sender, DragEventArgs e)
        {
            string[] files = (string[]) e.Data.GetData(DataFormats.FileDrop);
            StringBuilder buffer = new StringBuilder();

            foreach (string filename in files)
            {
                try
                {
                    string text = File.ReadAllText(filename);
                    buffer.Append(text);
                }
                catch (Exception ex)
                {
                    string errMsg = string.Format("cannot read the file\"{0}\" error: {1}", filename, ex.Message);
                    MessageBox.Show(errMsg, "Reading file error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    return;
                }
            }

            msg_textBox.Text = buffer.ToString();
        }

Solution

  • Somewhere you have set msg_textBox.EnableAutoDragDrop = true, either in your designer window or your code. You need to set this to false. You do still need to set AllowDrop = true.

    When set to true, the winforms RichTextBox provides standard behaviors for drag-and-drop events, to which your custom handlers are added. If you don't want the standard behavior, you have to completely roll your own handlers. (The standard behavior for a dropped text file is OLE embedding. If you double click on the icon, notepad launches.)