用户在我的DataGridView中上下拖动行。我有拖动逻辑，但我希望有一个黑色标记，指示在放开鼠标后行将放置在哪里。
Example from Microsoft Access http://img718.imageshack.us/img718/8171/accessdrag.png
来自Microsoft Access的示例;我想拖动行而不是列
有谁知道我会怎么做？这是内置的，还是我必须绘制自己的标记（如果是这样，我该怎么做）？
谢谢！
答案 0 :(得分：3)
MouseMove事件。
在发生拖动时，您的MouseMove处理程序应该：
DataGridView.PointToClient()将它们转换为相对坐标。DataGridViewRow.DividerHeight属性。如果您想使用鼠标下方的行外观进行自定义操作（而不是仅使用可用属性），则可以使用DataGridView.RowPostPaint事件。如果为此事件实现处理程序，该处理程序仅在将行拖过另一行时使用，则可以使用更粗的画笔重新绘制行的顶部或底部边框。 MSDN example here.
答案 1 :(得分：3)
这是我最终的解决方案。这个控制：
您可以使用此代码执行任何操作（无保修等）
using System;
using System.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
namespace CAM_Products.General_Controls
{
public class DataGridViewWithDraggableRows : DataGridView
{
private int? _predictedInsertIndex; //Index to draw divider at. Null means no divider
private Timer _autoScrollTimer;
private int _scrollDirection;
private static DataGridViewRow _selectedRow;
private bool _ignoreSelectionChanged;
private static event EventHandler<EventArgs> OverallSelectionChanged;
private SolidBrush _dividerBrush;
private Pen _selectionPen;
#region Designer properties
/// <summary>
/// The color of the divider displayed between rows while dragging
/// </summary>
[Browsable(true)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
[Category("Appearance")]
[Description("The color of the divider displayed between rows while dragging")]
public Color DividerColor
{
get { return _dividerBrush.Color; }
set { _dividerBrush = new SolidBrush(value); }
}
/// <summary>
/// The color of the border drawn around the selected row
/// </summary>
[Browsable(true)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
[Category("Appearance")]
[Description("The color of the border drawn around the selected row")]
public Color SelectionColor
{
get { return _selectionPen.Color; }
set { _selectionPen = new Pen(value); }
}
/// <summary>
/// Height (in pixels) of the divider to display
/// </summary>
[Browsable(true)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
[Category("Appearance")]
[Description("Height (in pixels) of the divider to display")]
[DefaultValue(4)]
public int DividerHeight { get; set; }
/// <summary>
/// Width (in pixels) of the border around the selected row
/// </summary>
[Browsable(true)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
[Category("Appearance")]
[Description("Width (in pixels) of the border around the selected row")]
[DefaultValue(3)]
public int SelectionWidth { get; set; }
#endregion
#region Form setup
public DataGridViewWithDraggableRows()
{
InitializeProperties();
SetupTimer();
}
private void InitializeProperties()
{
#region Code stolen from designer
this.AllowDrop = true;
this.AllowUserToAddRows = false;
this.AllowUserToDeleteRows = false;
this.AllowUserToOrderColumns = true;
this.AllowUserToResizeRows = false;
this.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
this.ColumnHeadersBorderStyle = DataGridViewHeaderBorderStyle.Single;
this.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
this.EnableHeadersVisualStyles = false;
this.MultiSelect = false;
this.ReadOnly = true;
this.RowHeadersVisible = false;
this.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
this.CellMouseDown += dataGridView1_CellMouseDown;
this.DragOver += dataGridView1_DragOver;
this.DragLeave += dataGridView1_DragLeave;
this.DragEnter += dataGridView1_DragEnter;
this.Paint += dataGridView1_Paint_Selection;
this.Paint += dataGridView1_Paint_RowDivider;
this.DefaultCellStyleChanged += dataGridView1_DefaultcellStyleChanged;
this.Scroll += dataGridView1_Scroll;
#endregion
_ignoreSelectionChanged = false;
OverallSelectionChanged += OnOverallSelectionChanged;
_dividerBrush = new SolidBrush(Color.Red);
_selectionPen = new Pen(Color.Blue);
DividerHeight = 4;
SelectionWidth = 3;
}
#endregion
#region Selection
/// <summary>
/// All instances of this class share an event, so that only one row
/// can be selected throughout all instances.
/// This method is called when a row is selected on any DataGridView
/// </summary>
private void OnOverallSelectionChanged(object sender, EventArgs e)
{
if(sender != this && SelectedRows.Count != 0)
{
ClearSelection();
Invalidate();
}
}
protected override void OnSelectionChanged(EventArgs e)
{
if(_ignoreSelectionChanged)
return;
if(SelectedRows.Count != 1 || SelectedRows[0] != _selectedRow)
{
_ignoreSelectionChanged = true; //Following lines cause event to be raised again
if(_selectedRow == null || _selectedRow.DataGridView != this)
{
ClearSelection();
}
else
{
_selectedRow.Selected = true; //Deny new selection
if(OverallSelectionChanged != null)
OverallSelectionChanged(this, EventArgs.Empty);
}
_ignoreSelectionChanged = false;
}
else
{
base.OnSelectionChanged(e);
if(OverallSelectionChanged != null)
OverallSelectionChanged(this, EventArgs.Empty);
}
}
public void SelectRow(int rowIndex)
{
_selectedRow = Rows[rowIndex];
_selectedRow.Selected = true;
Invalidate();
}
#endregion
#region Selection highlighting
private void dataGridView1_Paint_Selection(object sender, PaintEventArgs e)
{
if(_selectedRow == null || _selectedRow.DataGridView != this)
return;
Rectangle displayRect = GetRowDisplayRectangle(_selectedRow.Index, false);
if(displayRect.Height == 0)
return;
_selectionPen.Width = SelectionWidth;
int heightAdjust = (int)Math.Ceiling((float)SelectionWidth/2);
e.Graphics.DrawRectangle(_selectionPen, displayRect.X - 1, displayRect.Y - heightAdjust,
displayRect.Width, displayRect.Height + SelectionWidth - 1);
}
private void dataGridView1_DefaultcellStyleChanged(object sender, EventArgs e)
{
DefaultCellStyle.SelectionBackColor = DefaultCellStyle.BackColor;
DefaultCellStyle.SelectionForeColor = DefaultCellStyle.ForeColor;
}
private void dataGridView1_Scroll(object sender, ScrollEventArgs e)
{
Invalidate();
}
#endregion
#region Drag-and-drop
protected override void OnDragDrop(DragEventArgs args)
{
if(args.Effect == DragDropEffects.None)
return;
//Convert to coordinates within client (instead of screen-coordinates)
Point clientPoint = PointToClient(new Point(args.X, args.Y));
//Get index of row to insert into
DataGridViewRow dragFromRow = (DataGridViewRow)args.Data.GetData(typeof(DataGridViewRow));
int newRowIndex = GetNewRowIndex(clientPoint.Y);
//Adjust index if both rows belong to same DataGridView, due to removal of row
if(dragFromRow.DataGridView == this && dragFromRow.Index < newRowIndex)
{
newRowIndex--;
}
//Clean up
RemoveHighlighting();
_autoScrollTimer.Enabled = false;
//Only go through the trouble if we're actually moving the row
if(dragFromRow.DataGridView != this || newRowIndex != dragFromRow.Index)
{
//Insert the row
MoveDraggedRow(dragFromRow, newRowIndex);
//Let everyone know the selection has changed
SelectRow(newRowIndex);
}
base.OnDragDrop(args);
}
private void dataGridView1_DragLeave(object sender, EventArgs e1)
{
RemoveHighlighting();
_autoScrollTimer.Enabled = false;
}
private void dataGridView1_DragEnter(object sender, DragEventArgs e)
{
e.Effect = (e.Data.GetDataPresent(typeof(DataGridViewRow))
? DragDropEffects.Move
: DragDropEffects.None);
}
private void dataGridView1_DragOver(object sender, DragEventArgs e)
{
if(e.Effect == DragDropEffects.None)
return;
Point clientPoint = PointToClient(new Point(e.X, e.Y));
//Note: For some reason, HitTest is failing when clientPoint.Y = dataGridView1.Height-1.
// I have no idea why.
// clientPoint.Y is always 0 <= clientPoint.Y < dataGridView1.Height
if(clientPoint.Y < Height - 1)
{
int newRowIndex = GetNewRowIndex(clientPoint.Y);
HighlightInsertPosition(newRowIndex);
StartAutoscrollTimer(e);
}
}
private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
{
if(e.Button == MouseButtons.Left && e.RowIndex >= 0)
{
SelectRow(e.RowIndex);
var dragObject = Rows[e.RowIndex];
DoDragDrop(dragObject, DragDropEffects.Move);
//TODO: Any way to make this *not* happen if they only click?
}
}
/// <summary>
/// Based on the mouse position, determines where the new row would
/// be inserted if the user were to release the mouse-button right now
/// </summary>
/// <param name="clientY">
/// The y-coordinate of the mouse, given with respectto the control
/// (not the screen)
/// </param>
private int GetNewRowIndex(int clientY)
{
int lastRowIndex = Rows.Count - 1;
//DataGridView has no cells
if(Rows.Count == 0)
return 0;
//Dragged above the DataGridView
if(clientY < GetRowDisplayRectangle(0, true).Top)
return 0;
//Dragged below the DataGridView
int bottom = GetRowDisplayRectangle(lastRowIndex, true).Bottom;
if(bottom > 0 && clientY >= bottom)
return lastRowIndex + 1;
//Dragged onto one of the cells. Depending on where in cell,
// insert before or after row.
var hittest = HitTest(2, clientY); //Don't care about X coordinate
if(hittest.RowIndex == -1)
{
//This should only happen when midway scrolled down the page,
//and user drags over header-columns
//Grab the index of the current top (displayed) row
return FirstDisplayedScrollingRowIndex;
}
//If we are hovering over the upper-quarter of the row, place above;
// otherwise below. Experimenting shows that placing above at 1/4
//works better than at 1/2 or always below
if(clientY < GetRowDisplayRectangle(hittest.RowIndex, false).Top
+ Rows[hittest.RowIndex].Height/4)
return hittest.RowIndex;
return hittest.RowIndex + 1;
}
private void MoveDraggedRow(DataGridViewRow dragFromRow, int newRowIndex)
{
dragFromRow.DataGridView.Rows.Remove(dragFromRow);
Rows.Insert(newRowIndex, dragFromRow);
}
#endregion
#region Drop-and-drop highlighting
//Draw the actual row-divider
private void dataGridView1_Paint_RowDivider(object sender, PaintEventArgs e)
{
if(_predictedInsertIndex != null)
{
e.Graphics.FillRectangle(_dividerBrush, GetHighlightRectangle());
}
}
private Rectangle GetHighlightRectangle()
{
int width = DisplayRectangle.Width - 2;
int relativeY = (_predictedInsertIndex > 0
? GetRowDisplayRectangle((int)_predictedInsertIndex - 1, false).Bottom
: Columns[0].HeaderCell.Size.Height);
if(relativeY == 0)
relativeY = GetRowDisplayRectangle(FirstDisplayedScrollingRowIndex, true).Top;
int locationX = Location.X + 1;
int locationY = relativeY - (int)Math.Ceiling((double)DividerHeight/2);
return new Rectangle(locationX, locationY, width, DividerHeight);
}
private void HighlightInsertPosition(int rowIndex)
{
if(_predictedInsertIndex == rowIndex)
return;
Rectangle oldRect = GetHighlightRectangle();
_predictedInsertIndex = rowIndex;
Rectangle newRect = GetHighlightRectangle();
Invalidate(oldRect);
Invalidate(newRect);
}
private void RemoveHighlighting()
{
if(_predictedInsertIndex != null)
{
Rectangle oldRect = GetHighlightRectangle();
_predictedInsertIndex = null;
Invalidate(oldRect);
}
else
{
Invalidate();
}
}
#endregion
#region Autoscroll
private void SetupTimer()
{
_autoScrollTimer = new Timer
{
Interval = 250,
Enabled = false
};
_autoScrollTimer.Tick += OnAutoscrollTimerTick;
}
private void StartAutoscrollTimer(DragEventArgs args)
{
Point position = PointToClient(new Point(args.X, args.Y));
if(position.Y <= Font.Height/2 &&
FirstDisplayedScrollingRowIndex > 0)
{
//Near top, scroll up
_scrollDirection = -1;
_autoScrollTimer.Enabled = true;
}
else if(position.Y >= ClientSize.Height - Font.Height/2 &&
FirstDisplayedScrollingRowIndex < Rows.Count - 1)
{
//Near bottom, scroll down
_scrollDirection = 1;
_autoScrollTimer.Enabled = true;
}
else
{
_autoScrollTimer.Enabled = false;
}
}
private void OnAutoscrollTimerTick(object sender, EventArgs e)
{
//Scroll up/down
FirstDisplayedScrollingRowIndex += _scrollDirection;
}
#endregion
}
}
答案 2 :(得分：1)
我正在处理的应用程序将标记作为单独的Panel对象，其高度为1，BackColor为1.Panel对象保持隐藏状态，直到拖放实际进行为止。在DragOver事件上触发的此函数实现了大部分逻辑：
public static void frameG_dragover(Form current_form, DataGridView FRAMEG, Panel drag_row_indicator, Point mousePos)
{
int FRAMEG_Row_Height = FRAMEG.RowTemplate.Height;
int FRAMEG_Height = FRAMEG.Height;
int Loc_X = FRAMEG.Location.X + 2;
Point clientPoint = FRAMEG.PointToClient(mousePos);
int CurRow = FRAMEG.HitTest(clientPoint.X, clientPoint.Y).RowIndex;
int Loc_Y = 0;
if (CurRow != -1)
{
Loc_Y = FRAMEG.Location.Y + ((FRAMEG.Rows[CurRow].Index + 1) * FRAMEG_Row_Height) - FRAMEG.VerticalScrollingOffset;
}
else
{
Loc_Y = FRAMEG.Location.Y + (FRAMEG.Rows.Count + 1) * FRAMEG_Row_Height;
}
int width_c = FRAMEG.Columns[0].Width + FRAMEG.Columns[1].Width + FRAMEG.Columns[2].Width;
if ((Loc_Y > (FRAMEG.Location.Y)) && (Loc_Y < (FRAMEG.Location.Y + FRAMEG_Height - FRAMEG_Row_Height))) //+ FRAMEG_Row_Height
{
drag_row_indicator.Location = new System.Drawing.Point(Loc_X, Loc_Y);
drag_row_indicator.Size = new Size(width_c, 1);
}
if (!drag_row_indicator.Visible)
drag_row_indicator.Visible = true;
}
除此之外，您只需在拖放完成或移出DataGridView后再次隐藏Panel。