Come trascinare e rilasciare le righe DataGridView l'una sotto l'altra?

Question

Ho DataGridView che ha associato un List<myClass> e l'ho ordinato per "Priority" proprietà in "myClass". Quindi voglio trascinare un "DataGridViewRow" in una determinata posizione per cambiare la proprietà "Priority".

Come "Trascinare &" Righe DataGridView ?. E come gestirlo?

Answer 1

ho trovato questo code sample su MSDN

notare quanto segue:

1). La proprietà DataGridView AllowDrop deve essere impostata su true (l'impostazione predefinita è false).

2). L'esempio qui sotto funziona quando il DataGridView è NOT con associazione a dati. Altrimenti genererà un'eccezione InvalidOperationException. Se è un database, è necessario modificare l'ordine degli articoli nel numero DataSource.

private Rectangle dragBoxFromMouseDown; 
private int rowIndexFromMouseDown; 
private int rowIndexOfItemUnderMouseToDrop; 
private void dataGridView1_MouseMove(object sender, MouseEventArgs e) 
{ 
    if ((e.Button & MouseButtons.Left) == MouseButtons.Left) 
    { 
     // If the mouse moves outside the rectangle, start the drag. 
     if (dragBoxFromMouseDown != Rectangle.Empty && 
      !dragBoxFromMouseDown.Contains(e.X, e.Y)) 
     { 

      // Proceed with the drag and drop, passing in the list item.      
      DragDropEffects dropEffect = dataGridView1.DoDragDrop(
      dataGridView1.Rows[rowIndexFromMouseDown], 
      DragDropEffects.Move); 
     } 
    } 
} 

private void dataGridView1_MouseDown(object sender, MouseEventArgs e) 
{ 
    // Get the index of the item the mouse is below. 
    rowIndexFromMouseDown = dataGridView1.HitTest(e.X, e.Y).RowIndex; 
if (rowIndexFromMouseDown != -1) 
    { 
     // Remember the point where the mouse down occurred. 
    // The DragSize indicates the size that the mouse can move 
    // before a drag event should be started.     
     Size dragSize = SystemInformation.DragSize; 

     // Create a rectangle using the DragSize, with the mouse position being 
     // at the center of the rectangle. 
     dragBoxFromMouseDown = new Rectangle(new Point(e.X - (dragSize.Width/2), 
                 e.Y - (dragSize.Height/2)), 
          dragSize); 
    } 
    else 
     // Reset the rectangle if the mouse is not over an item in the ListBox. 
     dragBoxFromMouseDown = Rectangle.Empty; 
} 

private void dataGridView1_DragOver(object sender, DragEventArgs e) 
{ 
    e.Effect = DragDropEffects.Move; 
} 

private void dataGridView1_DragDrop(object sender, DragEventArgs e) 
{ 
    // The mouse locations are relative to the screen, so they must be 
    // converted to client coordinates. 
    Point clientPoint = dataGridView1.PointToClient(new Point(e.X, e.Y)); 

    // Get the row index of the item the mouse is below. 
    rowIndexOfItemUnderMouseToDrop = 
     dataGridView1.HitTest(clientPoint.X, clientPoint.Y).RowIndex; 

    // If the drag operation was a move then remove and insert the row. 
    if (e.Effect== DragDropEffects.Move) 
    { 
     DataGridViewRow rowToMove = e.Data.GetData(
      typeof(DataGridViewRow)) as DataGridViewRow; 
     dataGridView1.Rows.RemoveAt(rowIndexFromMouseDown); 
     dataGridView1.Rows.Insert(rowIndexOfItemUnderMouseToDrop, rowToMove); 

    } 
}