如何获取DataGridView列'；s索引在MouseUp事件中，而不是在MouseDown事件中

System.Windows.Forms.DataGrid.HitTestInfo myHitTest;
myHitTest = dataGrid1.HitTest(e.X, e.Y);
int p = myHitTest.ColumnIndex;

您可以创建两个HitTestInfo对象，一个在MouseDown中，一个位于MouseUp中。

IMO，您还应该使用DataGridView.HitTestInfo类，而不是DataGrid.HitTestInfo，并尽量不调用或命名DataGridViews DataGrids，这与WPF类似但不同！

DataGridView.HitTestInfo myHitTestDown, myHitTestUp;
int visibleColumnDown, visibleColumnUp;
private void dataGrid1_MouseUp(object sender, MouseEventArgs e)
{
    myHitTestUp = dataGrid1.HitTest(e.X, e.Y);
    visibleColumnUp = getVisibleColumn(dataGrid1, e.X);
}
private void dataGrid1_MouseDown(object sender, MouseEventArgs e)
{
    myHitTestDown = dataGrid1.HitTest(e.X, e.Y);
    visibleColumnDown = getVisibleColumn(dataGrid1, e.X);
}

更新：要在列被重新排序后找到列的可见索引，只需使用：

dataGrid1.Columns[myHitTestUp.ColumnIndex].DisplayIndex;

在我发现这一点之前，我写了一个小助手函数，它起到了同样的作用：

int getVisibleColumn(DataGridView dgv, int x)
{
    int cx = dgv.RowHeadersWidth;
    int c = 0;
    foreach (DataGridViewColumn col in dgv.Columns)
    {
        cx += col.Width; if ( cx >= x) return c; c++;
    }
    return -1;
}

要找出哪一列被打乱了似乎有点困难。有一个事件，它会为受影响的每个列调用，并且它总是首先为被拖动的列调用。这里有一种方法：

创建到类级别的变量：

List<DataGridViewColumn> shuffled = new List<DataGridViewColumn>();
DataGridViewColumn shuffledColumn = null;

记住第一列：

private void dgvLoadTable_ColumnDisplayIndexChanged(
             object sender, DataGridViewColumnEventArgs e)
{
    if (shuffledColumn == null) shuffledColumn = e.Column;
}

忘记之前发生的事情：

private void dgvLoadTable_MouseDown(object sender, MouseEventArgs e)
{  
    shuffledColumn = null;
}

现在你可以使用它了。然而，选择列并不能很好地洗牌！如果你做

 shuffledColumn.Selected = true;

只有当SelectionMode是FullColumnSelect或ColumnHeaderSelect时才会选择它——恐怕在任何一种模式下，混洗都不起作用。。

您可以使用drag'n'drop
假设您有一个Form和一个名为dataGridView1的DataGridView。

最初不要忘记允许对DataGridView:进行拖放

dataGridView1.AllowDrop = true;

替换MouseUp所需功能的事件处理程序是dataGridView1_DragDrop，目标列的索引是colIndexOfItemUnderMouseToDrop:

private Rectangle dragBoxFromMouseDown;
private int colIndexFromMouseDown;
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.                    
            dataGridView1.DoDragDrop(colIndexFromMouseDown, DragDropEffects.Move);
        }
    }
}
private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
{
    // Get the index of the item the mouse is below.
    colIndexFromMouseDown = dataGridView1.HitTest(e.X, e.Y).ColumnIndex;
    if (colIndexFromMouseDown != -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)
{
    // If the drag operation was a move then remove and insert the column.
    if (e.Effect == DragDropEffects.Move)
    {
        // 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 column index of the item the mouse is below. 
        int colIndexOfItemUnderMouseToDrop = dataGridView1.HitTest(clientPoint.X, clientPoint.Y).ColumnIndex;
        if (colIndexOfItemUnderMouseToDrop == -1)
            return;
        colIndexOfItemUnderMouseToDrop = dataGridView1.Columns[colIndexOfItemUnderMouseToDrop].DisplayIndex;
        // Now we have the column's display index.
        if (e.Data.GetDataPresent(typeof(int)))
        {
            int colToMove = (int)e.Data.GetData(typeof(int));
            dataGridView1.Columns[colToMove].DisplayIndex = colIndexOfItemUnderMouseToDrop;
            // Select the column:
            dataGridView1.Columns[colToMove].Selected = true;
        }
    }
}

编辑
新方法：

private DataGridViewColumn columnToMove;
public Form1()
{
    InitializeComponent();
    dataGridView1.Columns.AddRange(new DataGridViewColumn[]
        {
            new DataGridViewTextBoxColumn { Name = "AAA", SortMode = DataGridViewColumnSortMode.NotSortable },
            new DataGridViewTextBoxColumn { Name = "BBB", SortMode = DataGridViewColumnSortMode.NotSortable },
            new DataGridViewTextBoxColumn { Name = "CCC", SortMode = DataGridViewColumnSortMode.NotSortable }
        });
    dataGridView1.Rows.Add(2);
    dataGridView1.AllowUserToOrderColumns = true;
    dataGridView1.MouseDown += dataGridView1_MouseDown;
    dataGridView1.ColumnDisplayIndexChanged += dataGridView1_ColumnDisplayIndexChanged;
}
private void dataGridView1_ColumnDisplayIndexChanged(object sender, DataGridViewColumnEventArgs e)
{
    if (e.Column == columnToMove)
    {
        dataGridView1.SelectionMode = DataGridViewSelectionMode.ColumnHeaderSelect;
        e.Column.Selected = true;
    }
}
private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
{
    var hti = dataGridView1.HitTest(e.X, e.Y);
    if (hti.Type == DataGridViewHitTestType.ColumnHeader)
    {
        columnToMove = dataGridView1.Columns[hti.ColumnIndex];
        dataGridView1.SelectionMode = DataGridViewSelectionMode.RowHeaderSelect;
    }
}