1.思路主要代码
wpf的gridline原本效果是虚线类型的。有时候需要设计成表格形式的，因此有了用附加属性来自动绘制边框线的想法。
思路：绘制Line并添加到grid的children里，但效果并不理想，会出现锯齿，像素对齐，模糊等问题。
UseLayoutRounding="False"
SnapsToDevicePixels="True"
RenderOptions.EdgeModeProperty 貌似都没起作用。
于是想到了用border来实现，简单又实用吧 哈哈。
大致思路如下：绘制border的左边框和上边框，在边界的时候考虑边界封闭。然后将border平移一半的距离。这样边框就居中并且包围了所有的线。
主要代码如下：
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
namespace 用附加属性修改Grid的边框
{
public class GridHelper
{
private static void RefreshGrid(Grid grid, int lineWidth, Brush color)
{
for (var i = grid.Children.Count - 1; i > 0; i--)
{
var child = grid.Children[i];
var bd = child as Border;
if (bd != null && bd.Tag != null && bd.Tag.ToString() == "gridline")
{
grid.Children.Remove(bd);
}
}
var rows = grid.RowDefinitions.Count;
var cols = grid.ColumnDefinitions.Count;
//边界考虑
if (rows == 0)
{
rows = 1;
}
if (cols == 0)
{
cols = 1;
}
//生成行列
for (var i = 0; i < rows; i++)
{
for (var j = 0; j < cols; j++)
{
var thick = new Thickness(lineWidth, lineWidth, 0, 0);
var margin = new Thickness(-lineWidth/2d, -lineWidth/2d, 0, 0);
//边界考虑
if (i == 0)
{
margin.Top = 0;
}
if (i == rows - 1)
{
thick.Bottom = lineWidth;
}
if (j == 0)
{
margin.Left = 0;
}
if (j == cols - 1)
{
thick.Right = lineWidth;
}
var bd = new Border
{
BorderThickness = thick,
Margin = margin,
BorderBrush = color,
Tag = "gridline"
};
Grid.SetRow(bd, i);
Grid.SetColumn(bd, j);
grid.Children.Add(bd);
}
}
grid.InvalidateArrange();
grid.InvalidateVisual();
}
#region 线颜色
// Using a DependencyProperty as the backing store for LineColor. This enables animation, styling, binding, etc...
public static readonly DependencyProperty LineColorProperty =
DependencyProperty.RegisterAttached("LineColor", typeof (Brush), typeof (GridHelper),
new PropertyMetadata(Brushes.Black, LineColorPropertyChanged));
public static Brush GetLineColor(DependencyObject obj)
{
return (Brush) obj.GetValue(LineColorProperty);
}
public static void SetLineColor(DependencyObject obj, Brush value)
{
obj.SetValue(LineColorProperty, value);
}
private static void LineColorPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var grid = d as Grid;
if (grid == null)
{
return;
}
var showLines = GetShowGridLines(grid);
var color = GetLineColor(grid);
var lineWidth = GetLineWidth(grid);
if (showLines)
{
// grid.SnapsToDevicePixels = true;
grid.Loaded += delegate { RefreshGrid(grid, lineWidth, color); };
}
}
#endregion
#region 线宽度
// Using a DependencyProperty as the backing store for LineWidth. This enables animation, styling, binding, etc...
public static readonly DependencyProperty LineWidthProperty =
DependencyProperty.RegisterAttached("LineWidth", typeof (int), typeof (GridHelper),
new PropertyMetadata(1, LineWidthPropertyChanged));
public static int GetLineWidth(DependencyObject obj)
{
return (int) obj.GetValue(LineWidthProperty)
;
}
public static void SetLineWidth(DependencyObject obj, int value)
{
obj.SetValue(LineWidthProperty, value);
}
private static void LineWidthPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var grid = d as Grid;
if (grid == null)
{
return;
}
var showLines = GetShowGridLines(grid);
var color = GetLineColor(grid);
var lineWidth = GetLineWidth(grid);
if (showLines)
{
// grid.SnapsToDevicePixels = true;
grid.Loaded += delegate { RefreshGrid(grid, lineWidth, color); };
}
}
#endregion
#region 是否显示线
// Using a DependencyProperty as the backing store for ShowGridLines. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ShowGridLinesProperty =
DependencyProperty.RegisterAttached("ShowGridLines", typeof (bool), typeof (GridHelper),
new PropertyMetadata(false, ShowGridLinesPropertyChanged));
public static bool GetShowGridLines(DependencyObject obj)
{
return (bool) obj.GetValue(ShowGridLinesProperty);
}
public static void SetShowGridLines(DependencyObject obj, bool value)
{
obj.SetValue(ShowGridLinesProperty, value);
}
private static void ShowGridLinesPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var grid = d as Grid;
if (grid == null)
{
return;
}
var showLines = GetShowGridLines(grid);
var color = GetLineColor(grid);
var lineWidth = GetLineWidth(grid);
if (showLines)
{
// grid.SnapsToDevicePixels = true;
grid.Loaded += delegate { RefreshGrid(grid, lineWidth, color); };
}
}
#endregion
}
}
2.效果图
效果还可以，任何分辨率下，任何边框大小，都没有出现像素对齐或者模糊问题。 图中的虚线是grid的默认gridLine，红色和绿色是自定义的gridline，跟虚线完美重合。
3.源码下载
https://files.cnblogs.com/files/chlm/%E7%94%A8%E9%99%84%E5%8A%A0%E5%B1%9E%E6%80%A7%E4%BF%AE%E6%94%B9Grid%E7%9A%84%E8%BE%B9%E6%A1%86.rar