您可以使用以下代码.我已经对其进行了测试，它可以将单元格数据从一个 datagridview 复制到另一个.

You can use following code. I have tested it and it is working for copying cell data from one datagridview to another.

        private void dataGridView2_DragEnter(object sender, DragEventArgs e)
    {
        e.Effect = DragDropEffects.Copy;
    }

    /* Drag & Drop */
    private Rectangle dragBoxFromMouseDown;
    private object valueFromMouseDown;
    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(valueFromMouseDown, DragDropEffects.Copy);
            }
        }
    }

    private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
    {
        // Get the index of the item the mouse is below.
        var hittestInfo = dataGridView1.HitTest(e.X, e.Y);

        if (hittestInfo.RowIndex != -1 && hittestInfo.ColumnIndex != -1)
        {
            valueFromMouseDown = dataGridView1.Rows[hittestInfo.RowIndex].Cells[hittestInfo.ColumnIndex].Value;
            if (valueFromMouseDown != null)
            {
                // 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 dataGridView2_DragOver(object sender, DragEventArgs e)
    {
        e.Effect = DragDropEffects.Copy;
    }

    private void dataGridView2_DragDrop(object sender, DragEventArgs e)
    {
        // The mouse locations are relative to the screen, so they must be 
        // converted to client coordinates.
        Point clientPoint = dataGridView2.PointToClient(new Point(e.X, e.Y));

        // If the drag operation was a copy then add the row to the other control.
        if (e.Effect == DragDropEffects.Copy)
        {
            string cellvalue = e.Data.GetData(typeof(string)) as string;
            var hittest = dataGridView2.HitTest(clientPoint.X, clientPoint.Y);
            if (hittest.ColumnIndex != -1
                && hittest.RowIndex != -1)
                dataGridView2[hittest.ColumnIndex, hittest.RowIndex].Value = cellvalue;

        }
    }