如何为自定义网格控件设置自定义背景依赖属性

Question

我使用了网上找到的一个示例来创建自定义网格控件。它允许我放置我想要制作日历的网格线。但现在当我去设置背景时，它会阻止我的自定义网格线显示。

我知道这是因为 OnRender 首先被调用，然后背景正在摆脱我的自定义设置。我摆脱了 OnRender 上的覆盖，但仍然没有运气。所以我的问题是如何制作一个仍然允许显示网格线的自定义背景。

这是我想要的自定义控件的背景：如果我尝试将其添加到自定义控件中，我的网格线就会消失。

    <Grid.Background>
        <RadialGradientBrush>
            <GradientStop Color="#FFC3D6F5" Offset="0" />
            <GradientStop Color="#FFEFF5FF" Offset="1" />
        </RadialGradientBrush>
    </Grid.Background>

这是我在网上找到的自定义控件。它仅设置自定义网格线属性。我现在需要一个自定义背景属性。这有点困难，因为我的背景不是纯色的。

namespace Camp_
{    
public class GridControl : Grid
{

    #region Properties
    public bool ShowCustomGridLines
    {
        get { return (bool)GetValue(ShowCustomGridLinesProperty); }
        set { SetValue(ShowCustomGridLinesProperty, value); }
    }



    public static readonly DependencyProperty ShowCustomGridLinesProperty =
        DependencyProperty.Register("ShowCustomGridLines", typeof(bool), typeof(GridControl), new UIPropertyMetadata(false));

    public Brush GridLineBrush
    {
        get { return (Brush)GetValue(GridLineBrushProperty); }
        set { SetValue(GridLineBrushProperty, value); }
    }


    public static readonly DependencyProperty GridLineBrushProperty =
        DependencyProperty.Register("GridLineBrush", typeof(Brush), typeof(GridControl), new UIPropertyMetadata(Brushes.Black));



    public double GridLineThickness
    {
        get { return (double)GetValue(GridLineThicknessProperty); }
        set { SetValue(GridLineThicknessProperty, value); }
    }

    public static readonly DependencyProperty GridLineThicknessProperty =
        DependencyProperty.Register("GridLineThickness", typeof(double), typeof(GridControl), new UIPropertyMetadata(1.0));
    #endregion

    protected override void OnRender(DrawingContext dc)
    {  

        if (ShowCustomGridLines)
        {

            foreach (var rowDefinition in RowDefinitions)
            {
                dc.DrawLine(new Pen(GridLineBrush, GridLineThickness), new Point(0, rowDefinition.Offset), new Point(ActualWidth, rowDefinition.Offset));
            }

            foreach (var columnDefinition in ColumnDefinitions)
            {
                dc.DrawLine(new Pen(GridLineBrush, GridLineThickness), new Point(columnDefinition.Offset, 0), new Point(columnDefinition.Offset, ActualHeight));
            } 
            dc.DrawRectangle(Brushes.Transparent, new Pen(GridLineBrush, GridLineThickness), new Rect(0, 0, ActualWidth, ActualHeight));
        }
        base.OnRender(dc);
    }

    static GridControl()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(GridControl), new FrameworkPropertyMetadata(typeof(GridControl)));
    }
}
}

以及 XAML：

<customgridcontrol:GridControl ShowCustomGridLines="True" GridLineBrush="CornflowerBlue" ShowGridLines="False" >
                    <Grid.RowDefinitions>
                        <RowDefinition />
                        <RowDefinition />
                        <RowDefinition />
                        <RowDefinition />
                        <RowDefinition />
                        <RowDefinition />
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition />
                        <ColumnDefinition />
                        <ColumnDefinition />
                        <ColumnDefinition />
                        <ColumnDefinition />
                        <ColumnDefinition />
                        <ColumnDefinition />
                    </Grid.ColumnDefinitions>
</customgridcontrol:GridControl>

Answer 1

我认为你只需要在xaml代码中设置标准背景属性，如下所示：

<customgridcontrol:GridControl ShowCustomGridLines="True" GridLineBrush="CornflowerBlue" ShowGridLines="False" Background="Binding{ StaticResource BrushYouWantTo" >
                <Grid.RowDefinitions>
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>
</customgridcontrol:GridControl>

“你想要的画笔”必须在xaml代码中设置为资源，如下所示：

<Window.Resources>
   <RadialGradientBrush Name="BrushYouWantTo">
      <GradientStop Color="#FFC3D6F5" Offset="0" />
      <GradientStop Color="#FFEFF5FF" Offset="1" />
   </RadialGradientBrush>
</Window.Resources>

但是如果你想在程序运行时更改背景颜色您需要一个依赖属性和一个重新加载 GUI 的事件处理程序。要使用此事件处理程序，您必须使用 a 定义它

new UIPropertyMetadata(CustomGridBackgroundChanged)

并且事件处理程序定义可以如下所示：

  private static void CustomGridBackgroundChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
  {
     WindowName win = (WindowName)sender;
     if (win.PropertyChanged != null)
     {
        // at this place the gui will be reloaded
        win.PropertyChanged(win, new PropertyChangedEventArgs(null));
     }
  }

这只是一个想法，所以我真的不知道它在实践中是否有效...
但我希望它对你有一点帮助