Nic*_*ell 15 c# data-binding wpf styles controltemplate
我知道这是一个很受欢迎的问题,但我找不到任何可以回答的问题,但如果我在搜索中遗漏了一些内容,我会道歉.
我正在尝试使用以下代码在运行时创建并测量控件(然后测量将用于选框样式滚动控件 - 每个控件的大小不同):
Label lb = new Label();
lb.DataContext= task;
Style style = (Style)FindResource("taskStyle");
lb.Style = style;
cnvMain.Children.Insert(0,lb);
width = lb.RenderSize.Width;
width = lb.ActualWidth;
width = lb.Width;
代码创建一个Label控件并为其应用样式.该样式包含我的控件模板,该模板绑定到对象"任务".当我创建项目时它看起来很完美,但是当我尝试使用上面的任何属性测量控件时,我得到以下结果(我逐步检查并依次检查每个属性):
lb.Width = NaN
lb.RenderSize.Width = 0
lb.ActualWidth = 0
有没有办法获得您在运行时创建的控件的渲染高度和宽度？
更新:
很抱歉取消选择您的解决方案作为答案.他们在我设置的基本示例系统上工作,但似乎没有完整的解决方案.
我觉得它可能与风格有关,所以很抱歉这个烂摊子,但我在这里粘贴整个东西.
一,资源:
<Storyboard x:Key="mouseOverGlowLeave">
<DoubleAnimation From="8" To="0" Duration="0:0:1" BeginTime="0:0:2" Storyboard.TargetProperty="GlowSize" Storyboard.TargetName="Glow"/>
</Storyboard>
<Storyboard x:Key="mouseOverTextLeave">
<ColorAnimation From="{StaticResource buttonLitColour}" To="Gray" Duration="0:0:3" Storyboard.TargetProperty="Color" Storyboard.TargetName="ForeColour"/>
</Storyboard>
<Color x:Key="buttonLitColour" R="30" G="144" B="255" A="255" />
<Storyboard x:Key="mouseOverText">
<ColorAnimation From="Gray" To="{StaticResource buttonLitColour}" Duration="0:0:1" Storyboard.TargetProperty="Color" Storyboard.TargetName="ForeColour"/>
</Storyboard>
风格本身:
<Style x:Key="taskStyle" TargetType="Label">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Canvas x:Name="cnvCanvas">
<Border Margin="4" BorderBrush="Black" BorderThickness="3" CornerRadius="16">
<Border.Background>
<LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
<GradientStop Offset="1" Color="SteelBlue"/>
<GradientStop Offset="0" Color="dodgerBlue"/>
</LinearGradientBrush>
</Border.Background>
<DockPanel Margin="8">
<DockPanel.Resources>
<Style TargetType="TextBlock">
<Setter Property="FontFamily" Value="corbel"/>
<Setter Property="FontSize" Value="40"/>
</Style>
</DockPanel.Resources>
<TextBlock VerticalAlignment="Center" Margin="4" Text="{Binding Path=Priority}"/>
<DockPanel DockPanel.Dock="Bottom">
<Border Margin="4" BorderBrush="SteelBlue" BorderThickness="1" CornerRadius="4">
<TextBlock Margin="4" DockPanel.Dock="Right" Text="{Binding Path=Estimate}"/>
</Border>
<Border Margin="4" BorderBrush="SteelBlue" BorderThickness="1" CornerRadius="4">
<TextBlock Margin="4" DockPanel.Dock="Left" Text="{Binding Path=Due}"/>
</Border>
</DockPanel>
<DockPanel DockPanel.Dock="Top">
<Border Margin="4" BorderBrush="SteelBlue" BorderThickness="1" CornerRadius="4">
<TextBlock Margin="4" Foreground="LightGray" DockPanel.Dock="Left" Text="{Binding Path=List}"/>
</Border>
<Border Margin="4" BorderBrush="SteelBlue" BorderThickness="1" CornerRadius="4">
<TextBlock Margin="4" Foreground="White" DockPanel.Dock="Left" Text="{Binding Path=Name}"/>
</Border>
</DockPanel>
</DockPanel>
</Border>
</Canvas>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
另外,我正在使用的代码:
Label lb = new Label(); //the element I'm styling and adding
lb.DataContext= task; //set the data context to a custom class
Style style = (Style)FindResource("taskStyle"); //find the above style
lb.Style = style;
cnvMain.Children.Insert(0,lb); //add the style to my canvas at the top, so other overlays work
lb.UpdateLayout(); //attempt a full layout update - didn't work
Dispatcher.Invoke(DispatcherPriority.Render, new Action(() =>
{
//Synchronize on control rendering
double width = lb.RenderSize.Width;
width = lb.ActualWidth;
width = lb.Width;
})); //this didn't work either
lb.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity)); //nor did this
double testHeight = lb.DesiredSize.Height;
double testWidth = lb.RenderSize.Width; //nor did this
width2 = lb.ActualWidth; //or this
width2 = lb.Width; //or this
//positioning for my marquee code - position off-screen to start with
Canvas.SetTop(lb, 20);
Canvas.SetTop(lb, -999);
//tried it here too, still didn't work
lb.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
testHeight = lb.DesiredSize.Height;
//add my newly-created label to a list which I access later to operate the marquee
taskElements.AddLast(lb);
//still didn't work
lb.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
testHeight = lb.DesiredSize.Height;
//tried a mass-measure to see if that would work - it didn't
foreach (UIElement element in taskElements)
{
element.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
}
每次调用其中任何一个时,值都返回0或不是数字,但是当标签被渲染时,它显然具有可见的大小.当标签在屏幕上可见时,我尝试从按下按钮运行此代码,但产生相同的结果.
是因为我使用的风格？数据绑定也许？我做错了是不是很明显,还是WPF Gremlins 真的很讨厌我？
第二次更新:
进一步搜索后,我发现Measure()仅适用于原始元素大小.如果控件模板通过实际添加控件来修改它,那么最好的方法可能是测量每一个,但我承认这不仅有点凌乱.
编译器必须有某种方法来测量控件的所有内容,因为它必须使用它来放置项目,例如堆栈面板.必须有一些方法来访问它,但现在我完全没有想法.
Joe*_*ite 24
在WPF执行布局传递之前,控件将没有大小.我认为这是异步发生的.如果你在构造函数中这样做,你可以挂钩Loaded事件 - 那时布局就会发生,你在构造函数中添加的任何控件都会被调整大小.
但是,另一种方法是让控件计算它想要的大小.为此,您调用Measure,并将其传递给建议的大小.在这种情况下,您希望传递无限大小(意味着控件可以像它喜欢的那样大),因为这是Canvas在布局传递中要做的事情:
lb.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
Debug.WriteLine(lb.DesiredSize.Width);
对Measure的调用实际上并不会更改控件的Width,RenderSize或ActualWidth.它只是告诉Label计算它想要的大小,并将该值放入DesiredSize(一个属性,其唯一目的是保存最后一次Measure调用的结果).
解决了！
问题出在我的 XAML 中。在我的标签模板的最高级别，有一个没有高度或宽度字段的父画布。由于它不必为其子级修改其大小，因此它始终设置为 0,0。通过删除它并用边框替换根节点（边框必须调整大小以适合其子节点），高度和宽度字段将被更新并传播回 Measure() 调用时的代码。