示例：WPF中Grid显示网格线的几种方式

一、目的：介绍一下WPF中Grid显示网格线的几种方式

二、几种方式

1、重写OnRender绘制网格线（推荐）

效果如下：

实现方式如下：

    public class LineGrid : Grid{private readonly Pen _pen;public LineGrid(){_pen = new Pen(SystemColors.ActiveBorderBrush, 1);_pen.Freeze();}protected override void OnRender(DrawingContext dc){base.OnRender(dc);foreach (RowDefinition item in this.RowDefinitions){dc.DrawLine(_pen, new Point(0, item.Offset), new Point(this.ActualWidth, item.Offset));}dc.DrawLine(_pen, new Point(0, this.ActualHeight), new Point(this.ActualWidth, this.ActualHeight));foreach (ColumnDefinition item in this.ColumnDefinitions){dc.DrawLine(_pen, new Point(item.Offset, 0), new Point(item.Offset, this.ActualHeight));}dc.DrawLine(_pen, new Point(this.ActualWidth, 0), new Point(this.ActualWidth, this.ActualHeight));}}

                    <local:LineGrid Margin="50"><Grid.RowDefinitions><RowDefinition /><RowDefinition Height="50" /><RowDefinition Height="50" /><RowDefinition Height="50" /><RowDefinition Height="50" /></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinition /><ColumnDefinition Width="100" /></Grid.ColumnDefinitions><TextBlockGrid.Row="0"Grid.RowSpan="2"Grid.Column="5"Margin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"Background="White"Text="LineGrid" /><LabelMargin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"HorizontalContentAlignment="Center"VerticalContentAlignment="Center"Background="White"Content="Center"FontSize="50" /></local:LineGrid>

优点：通过OnRender绘制复杂度低，性能较好

缺点：需要单独定义LineGrid类重写OnRender ，但相对来说实现比较简单，复用性比较高

2、使用ShowGridLines属性

效果如下：

实现代码

                    <Grid Margin="50" ShowGridLines="True"><Grid.RowDefinitions><RowDefinition /><RowDefinition Height="50" /><RowDefinition Height="50" /><RowDefinition Height="50" /><RowDefinition Height="50" /></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinition /><ColumnDefinition Width="100" /></Grid.ColumnDefinitions><TextBlockGrid.Row="0"Grid.RowSpan="2"Grid.Column="5"Margin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"Background="White"Text="LineGrid" /><LabelMargin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"HorizontalContentAlignment="Center"VerticalContentAlignment="Center"Background="White"Content="Center"FontSize="50" /></Grid>

优点：Grid自带功能，直接设置 ShowGridLines="True"即可

缺点：样式固定且单一，一般来说是不能满足需求

3、使用Adorner绘制

效果如下：

实现代码：

定义Adorner

    public class GridLineAdorner : Adorner{public GridLineAdorner(UIElement adornedElement) : base(adornedElement){}protected override void OnRender(DrawingContext dc){base.OnRender(dc);Grid grid = this.AdornedElement as Grid;if (grid == null)return;Pen pen = new Pen(SystemColors.HighlightBrush, 1);foreach (RowDefinition item in grid.RowDefinitions){dc.DrawLine(pen, new Point(0, item.Offset), new Point(this.ActualWidth, item.Offset));}dc.DrawLine(pen, new Point(0, grid.ActualHeight), new Point(this.ActualWidth, this.ActualHeight));foreach (ColumnDefinition item in grid.ColumnDefinitions){dc.DrawLine(pen, new Point(item.Offset, 0), new Point(item.Offset, this.ActualHeight));}dc.DrawLine(pen, new Point(this.ActualWidth, 0), new Point(this.ActualWidth, this.ActualHeight));}}

（注：这部分目前没有实现Rowspan和Columnspan网线的遮挡，有需求的可以使用PushClip方式实现）

Xaml中添加代码

        <AdornerDecorator><Grid Margin="50" Loaded="GridLine_Loaded"><Grid.RowDefinitions><RowDefinition /><RowDefinition Height="50" /><RowDefinition Height="50" /><RowDefinition Height="50" /><RowDefinition Height="50" /></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinition /><ColumnDefinition Width="100" /></Grid.ColumnDefinitions><TextBlockGrid.Row="0"Grid.RowSpan="2"Grid.Column="5"Margin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"Background="White"Text="LineGrid" /><LabelMargin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"HorizontalContentAlignment="Center"VerticalContentAlignment="Center"Background="White"Content="Center"FontSize="50" /></Grid></AdornerDecorator>

在Loaded时给Grid添加Adoner

        private void GridLine_Loaded(object sender, RoutedEventArgs e){Grid grid = sender as Grid;GridLineAdorner gridLineAdorner = new GridLineAdorner(grid);var layer = AdornerLayer.GetAdornerLayer(grid);layer.Add(gridLineAdorner);}

优点：定义成Adorner复用性比较高

缺点：实现和添加相对复杂些，但一劳永逸，也可以把Loaded部分封装成附加属性调用这样就可以不用单独处理事件

4、使用GridLineAttach附加属性，添加Border的方式绘制

效果如下：

实现代码：

定义附加属性

    public class GridLineAttach{public static bool GetUse(DependencyObject obj){return (bool)obj.GetValue(UseProperty);}public static void SetUse(DependencyObject obj, bool value){obj.SetValue(UseProperty, value);}public static readonly DependencyProperty UseProperty =DependencyProperty.RegisterAttached("Use", typeof(bool), typeof(GridLineAttach), new PropertyMetadata(default(bool), OnUseChanged));static public void OnUseChanged(DependencyObject d, DependencyPropertyChangedEventArgs e){Grid grid = d as Grid;if (grid == null)return;bool n = (bool)e.NewValue;grid.Loaded -= Grid_Loaded;if (n)grid.Loaded += Grid_Loaded;}private static void Grid_Loaded(object sender, RoutedEventArgs e){Grid grid = sender as Grid;var controls = grid.Children;var count = controls.Count;for (int i = 0; i < count; i++){var item = controls[i] as FrameworkElement;var border = new Border(){BorderBrush = SystemColors.ActiveBorderBrush,BorderThickness = new Thickness(1)};var row = Grid.GetRow(item);var column = Grid.GetColumn(item);var rowspan = Grid.GetRowSpan(item);var columnspan = Grid.GetColumnSpan(item);Grid.SetRow(border, row);Grid.SetColumn(border, column);Grid.SetRowSpan(border, rowspan);Grid.SetColumnSpan(border, columnspan);grid.Children.Add(border);}}}

给Grid添加附加属性

                    <Grid Margin="50" local:GridLineAttach.Use="True"><Grid.RowDefinitions><RowDefinition /><RowDefinition Height="50" /></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinition /><ColumnDefinition Width="100" /></Grid.ColumnDefinitions><TextBlockGrid.Row="0"Grid.RowSpan="2"Grid.Column="5"Margin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"Background="White"Text="LineGrid" /><LabelMargin="1"HorizontalAlignment="Stretch"VerticalAlignment="Stretch"HorizontalContentAlignment="Center"VerticalContentAlignment="Center"Background="White"Content="Center"FontSize="50" /><TextBlock Text="1" Grid.Row="1"/></Grid>

优点：定义成附加属性复用性比较高

缺点：额外添加了Border元素，对于数据量比较大的情况增加了渲染压力