How could I Drag and Drop DataGridView Rows under each other?

Question

I've DataGridView that bound a List<myClass> and i sort it by "Priority" property in "myClass". So I want to drag an "DataGridViewRow" to certain position to change it's "Priority" property.

How could I "Drag & Drop" DataGridView Rows ?. And how to handle this ?.

Answer 1

I found this code sample on MSDN

Note the following:

1). DataGridView property AllowDrop must be set to true (default is false).

2). The example below works out of the box when the DataGridView is NOT data-bound. Otherwise it will throw an InvalidOperationException. If it is databound, you should manipulate the order of items in the 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);      } }