GUI for File manipulation.

Assumptions:

1. All sections of all five files are to be displayed at once.
   
2. A section may not be moved twice.
   
3. When a section is dragged, it will be placed in the "target" area consecutively (i.e., order of dragged sections is in the order dragged).
   

I'd use two RichTextBoxes side-by-side to display the sections. The RichTextBox on the left contains the source sections; that on the right the selected sections. I would set off each file with some type of enclosing box (say, blue-dotted) and each section with a different type of enclosing box (say green-dotted).

I've used this type of GUI in Transfer and XFR Tools - Extensions [^] (see Extensions) and found it easy to implement. Note that the left and right containers in that article are ListBoxes not RichTextBoxes.

When the use clicks within a section, I'd change the shape of the cursor and the background color of the section box. Note you will need to handle MouseDown, MouseUp, and MouseMove events.

When the user releases the mouse button, and the mouse position is within the target RichTextBox, copy the contents of the source section box to the new target section box. (Initially, when moving the cursor, just show the cursor; later when everything works as desired, you can become more flashy by dragging the chosen section box and its contents as the cursor is moved).

Signal that a section has been moved by simply removing the contents of the source section and marking the section as immovable. Alternately, you could just remove the section entirely.

I would create a Form like this:

1. one horizontal split-container docked full, 'HSplit1

2. in the left panel of #1 a TreeView Control docked full, 'DocTreeView

3. in the right panel of #1 another horizontal split-container, 'HSplt2

4. in the left panel of #2 a TextBox docked full, 'SourceTextBox

5. in the right panel of #2 a TextBox docked full, 'DestinationTextBox

I would set-up the TreeView like this:

1. give the user some interface to select up to five files

2. add a root node for each file

3. parse each file to determine the sections

4. create child-nodes for each root-node internally linked to the sections of each file

The run-time behavior of the program: assuming the TreeView is filled properly

1. the user clicks on a root-node (file), and selects a section (child-node)

2. the text associated with that section is displlayed in the 'SourceTextBox

3. the user can select Text in the 'SourceTextBox and drag-drop it into the 'DestinationTextBox.

4. the Application would provide some useful interface for saving the contents of the 'DestinationTextBox, for changing the currently opened source files, rebuilding the TreeView, etc.

Notes:

1. The difficulty with drag-dropping from one TextBox (or RichTextBox) to another is that a mouse-down (default mouse-down) on the current selection will cause the selection to be cleared. To get around this: you need to use techniques like:

a. don't call 'DoDragDrop in the MouseDown unless the context-click mouse button is down; example:

private void SourceTextBox_MouseDown(object sender, MouseEventArgs e)
{
    if (MouseButtons == MouseButtons.Right)
    {
        SourceTextBox.DoDragDrop(SourceTextBox.SelectedText, DragDropEffects.Copy);
    }
}

b. use a modified WndProc and an over-ride of 'OnMouseDown; see: [^].

2. Why use horizontal splitters ? Answer: for the user's convenience in using the UI.

If you have further questions, please feel free to ask.