我正在wpf中重建自2011年以来运行良好的vb6应用程序。我的应用程序处理11个文档。在vb6中,我在MDI中使用了11种形式。
在wpf中,我使用的是名为Hold的Canvas。该画布包含11个我称为Doc的FrameworkElement实例。
Doc有一些方法可以为我称为Cell的类绘制形状和文本。为了将单元格放置在Doc中,需要Doc绘制网格。为此我有一个布尔字段(布尔_showGrid;),如果为true,则Doc将绘制网格。
我的问题是从xaml调用时Doc FrameworkElement不会绘制网格。但是从Window_Loaded可以。
这是Doc FrameworkElement的一部分:
public class Doc : FrameworkElement
{
VisualCollection paper;
DrawingVisual cellMaker;
bool _showGrid;
public Doc()
{
paper = new VisualCollection(this);
//SetValue(RenderOptions.EdgeModeProperty, EdgeMode.Aliased);
}
public bool showGrid
{
set
{
_showGrid = value;
if (_showGrid)
{
drawGrid();
}
}
}
private void drawGrid()
{
DrawingVisual grid = new DrawingVisual();
using(DrawingContext dc = grid.RenderOpen())
{
for(int i = 0; i <= Width; i += 18)
{
dc.DrawLine(new Pen(Brushes.OrangeRed, 1), new Point(i, 0), new Point(i, Height));
}
for(int j = 0; j <= Height; j += 18)
{
dc.DrawLine(new Pen(Brushes.OrangeRed, 1), new Point(0, j), new Point(Width, j));
}
dc.Close();
}
paper.Add(grid);
}
这是xaml,其中在showGrid中创建的docs的documentReceipt实例设置为true时,女巫不起作用:
<ScrollViewer Grid.Row="1" Grid.Column="0">
<Canvas Name="Hold" Width="21cm" Height="29.7cm" Background="White" Margin="17">
<dc:Doc Name="documentsReceipt"
Width="{Binding Path=ActualWidth,ElementName=Hold}"
Height="{Binding Path=ActualHeight,ElementName=Hold}"
showGrid="True"
Loaded="documentsReceipt_Loaded">
</dc:Doc>
<TextBox Name="txt"
TextChanged="txt_TextChanged"
KeyDown="txt_KeyDown"
PreviewKeyDown="txt_PreviewKeyDown"/>
</Canvas>
</ScrollViewer>
这是当我忽略了应用程序documentReceipt=true
从Window_Loaded
private void Window_Loaded(object sender, RoutedEventArgs e)
{
//documentsReceipt.showGrid = true;
}
通常,您实现的控件有点不同。首先,您需要一个依赖项属性以ShowGrid
使其可绑定。接下来是覆盖OnRender
以绘制形状(或其他形状)。这是控件的完整实现:
public class Doc : FrameworkElement
{
public bool ShowGrid
{
get { return (bool)GetValue (ShowGridProperty); }
set { SetValue (ShowGridProperty, value); }
}
public static readonly DependencyProperty ShowGridProperty =
DependencyProperty.Register ("ShowGrid", typeof (bool), typeof (Doc), new FrameworkPropertyMetadata (false, FrameworkPropertyMetadataOptions.AffectsRender));
protected override void OnRender (DrawingContext dc)
{
if (ShowGrid)
{
for (int i = 0; i <= ActualWidth; i += 18)
{
dc.DrawLine (new Pen (Brushes.OrangeRed, 1), new Point (i, 0), new Point (i, Height));
}
for (int j = 0; j <= ActualHeight; j += 18)
{
dc.DrawLine (new Pen (Brushes.OrangeRed, 1), new Point (0, j), new Point (Width, j));
}
}
}
}
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