[英]ScrollableControl draw border around entire control
我正在构建基于ScrollableControl
自定义用户控件。
现在,我正在尝试在控件周围添加边框(类似于DataGridView的边框)
我可以使用以下方法绘制边框:
e.Graphics.TranslateTransform(AutoScrollPosition.X*-1, AutoScrollPosition.Y*-1);
ControlPaint.DrawBorder(e.Graphics, ClientRectangle, Color.DarkBlue, ButtonBorderStyle.Dashed);
但这会在ClientRectangle周围绘制边框,而不是在整个控件周围绘制边框:
如上图所示,边框没有像DataGridView中那样环绕滚动条。
我可以在整个控件周围绘制边框,以使滚动条包含在边框所包围的区域中吗?
编辑:
基于Textbox的自定义onPaint,我可以通过覆盖WndProc
来绘制自定义边框,但是我得到了看起来很奇怪的边框闪烁:
这是我到目前为止的完整代码:
internal class TestControl : ScrollableControl
{
private int _tileWidth = 100;
private int _tileHeight = 100;
private int _tilesX = 20;
private int _tilesY = 20;
public TestControl()
{
SetStyle(ControlStyles.ResizeRedraw, true);
SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
SetStyle(ControlStyles.Opaque, true);
SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
UpdateStyles();
ResizeRedraw = true;
AutoScrollMinSize = new Size(_tilesX*_tileWidth, _tilesY*_tileHeight);
}
private bool _test = true;
[DefaultValue(true)]
public bool Test
{
get { return _test; }
set
{
if(_test==value) return;
_test = value;
Update();
}
}
[DllImport("user32")]
private static extern IntPtr GetWindowDC(IntPtr hwnd);
struct RECT
{
public int left, top, right, bottom;
}
struct NCCALSIZE_PARAMS
{
public RECT newWindow;
public RECT oldWindow;
public RECT clientWindow;
IntPtr windowPos;
}
int clientPadding = 1;
int actualBorderWidth = 1;
Color borderColor = Color.Black;
protected override void WndProc(ref Message m)
{
//We have to change the clientsize to make room for borders
//if not, the border is limited in how thick it is.
if (m.Msg == 0x83 && _test) //WM_NCCALCSIZE
{
if (m.WParam == IntPtr.Zero)
{
RECT rect = (RECT)Marshal.PtrToStructure(m.LParam, typeof(RECT));
rect.left += clientPadding;
rect.right -= clientPadding;
rect.top += clientPadding;
rect.bottom -= clientPadding;
Marshal.StructureToPtr(rect, m.LParam, false);
}
else
{
NCCALSIZE_PARAMS rects = (NCCALSIZE_PARAMS)Marshal.PtrToStructure(m.LParam, typeof(NCCALSIZE_PARAMS));
rects.newWindow.left += clientPadding;
rects.newWindow.right -= clientPadding;
rects.newWindow.top += clientPadding;
rects.newWindow.bottom -= clientPadding;
Marshal.StructureToPtr(rects, m.LParam, false);
}
}
if (m.Msg == 0x85 && _test) //WM_NCPAINT
{
base.WndProc(ref m);
IntPtr wDC = GetWindowDC(Handle);
using (Graphics g = Graphics.FromHdc(wDC))
{
ControlPaint.DrawBorder(g, new Rectangle(0, 0, Size.Width, Size.Height), borderColor, actualBorderWidth, ButtonBorderStyle.Solid,
borderColor, actualBorderWidth, ButtonBorderStyle.Solid, borderColor, actualBorderWidth, ButtonBorderStyle.Solid,
borderColor, actualBorderWidth, ButtonBorderStyle.Solid);
}
return;
}
base.WndProc(ref m);
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.FillRectangle(new SolidBrush(BackColor), ClientRectangle);
e.Graphics.TranslateTransform(AutoScrollPosition.X, AutoScrollPosition.Y);
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
var offsetX = (AutoScrollPosition.X*-1)/_tileWidth;
var offsetY = (AutoScrollPosition.Y*-1)/_tileHeight;
var visibleX = Width/_tileWidth + 2;
var visibleY = Height/_tileHeight + 2;
var x = Math.Min(visibleX + offsetX, _tilesX);
var y = Math.Min(visibleY + offsetY, _tilesY);
for (var i = offsetX; i < x; i++)
{
for (var j = offsetY; j < y; j++)
{
e.Graphics.FillRectangle(Brushes.Beige, new Rectangle(i*_tileWidth, j*_tileHeight, _tileWidth, _tileHeight));
e.Graphics.DrawString(string.Format("{0}:{1}", i, j), Font, Brushes.Black, new Rectangle(i*_tileWidth, j*_tileHeight, _tileWidth, _tileHeight));
}
}
using (var p = new Pen(Color.Black))
{
for (var i = offsetX + 1; i < x; i++)
{
e.Graphics.DrawLine(p, i*_tileWidth, 0, i*_tileWidth, y*_tileHeight);
}
for (var i = offsetY + 1; i < y; i++)
{
e.Graphics.DrawLine(p, 0, i*_tileHeight, x*_tileWidth, i*_tileHeight);
}
}
e.Graphics.FillRectangle(Brushes.White, AutoScrollPosition.X*-1 + 10, AutoScrollPosition.Y*-1 + 10, 35, 14);
e.Graphics.DrawString("TEST", DefaultFont, new SolidBrush(Color.Red), AutoScrollPosition.X*-1 + 10, AutoScrollPosition.Y*-1 + 10);
e.Graphics.TranslateTransform(AutoScrollPosition.X*-1, AutoScrollPosition.Y*-1);
ControlPaint.DrawBorder(e.Graphics, ClientRectangle, Color.Red, actualBorderWidth, ButtonBorderStyle.None,
Color.Red, actualBorderWidth, ButtonBorderStyle.None, Color.Red, actualBorderWidth, ButtonBorderStyle.Solid,
Color.Red, actualBorderWidth, ButtonBorderStyle.Solid);
}
protected override void OnScroll(ScrollEventArgs e)
{
if (DesignMode)
{
base.OnScroll(e);
return;
}
if (e.Type == ScrollEventType.First)
{
LockWindowUpdate(Handle);
}
else
{
LockWindowUpdate(IntPtr.Zero);
Update();
if (e.Type != ScrollEventType.Last) LockWindowUpdate(Handle);
}
}
protected override void OnMouseWheel(MouseEventArgs e)
{
if (VScroll && (ModifierKeys & Keys.Shift) == Keys.Shift)
{
VScroll = false;
LockWindowUpdate(Handle);
base.OnMouseWheel(e);
LockWindowUpdate(IntPtr.Zero);
Update();
VScroll = true;
}
else
{
LockWindowUpdate(Handle);
base.OnMouseWheel(e);
LockWindowUpdate(IntPtr.Zero);
Update();
}
}
[DllImport("user32.dll", SetLastError = true)]
private static extern bool LockWindowUpdate(IntPtr hWnd);
}
可以解决此闪烁问题吗?
我可以通过重写CreateParams
解决我的问题:
protected override CreateParams CreateParams
{
[SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= NativeMethods.WS_EX_CONTROLPARENT;
cp.ExStyle &= (~NativeMethods.WS_EX_CLIENTEDGE);
cp.Style &= (~NativeMethods.WS_BORDER);
cp.Style |= NativeMethods.WS_BORDER;
return cp;
}
}
这是必需的NativeMethods
类:
internal static class NativeMethods
{
public const int WS_EX_CONTROLPARENT = 0x00010000;
public const int WS_EX_CLIENTEDGE = 0x00000200;
public const int WS_BORDER = 0x00800000;
}
结果如下:
您可以简单地从UserControl
派生。 它具有用于显示滚动条的内置支持,还具有用于显示边框的内置支持。
可以将UserControl
所有内置功能添加到从ScrollableControl
派生的ScrollableControl
但是需要进行一些额外的尝试和错误工作,或者着眼于UserControl
源代码 。 但是使用UserControl
类可以简单地拥有这些功能。
显示边框
要显示边框,只需将其BorderStyle
设置为FixedSingle
即可获得所需的功能:
显示滚动条
要获得滚动功能,只需将其AutoScroll
设置为true,并设置合适的AutoScrollMinSize
进行控制即可。 然后,当控件的宽度或高度小于给定大小的宽度或高度时,将显示合适的滚动条。
自定义边框颜色
我还假设您希望控件具有不同的边框颜色,那么就足以覆盖WndProc
并处理WM_NCPAINT
并为控件绘制自定义边框,如下所示:
在上面的示例中,我使用了与更改TextBox的BorderColor相同的技术,只是做了很小的改动,在这里,我检查BorderStyle
等于FixedSingle
,然后绘制了具有所需颜色的边框。
使设计人员在设计时可以像父控件一样工作
如果要使设计者能够将某些控件放到UserControl
,就可以用[Designer(typeof(ParentControlDesigner))]
装饰它。 这样,当您将UserControl
放在窗体上时,它可以承载其他控件,例如面板控件。 如果您不喜欢此功能,请不要使用该属性来装饰它,并且默认情况下它将使用Control
设计器,该设计器的作用不像父控件。
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