我有一个Silverlight控件库“Controls”,其中定义了一个用于显示对话框的客户控件:
public class Dialog : ContentControl
{
public Dialog()
: base()
{
DefaultStyleKey = typeof(Dialog);
}
<...normal custom control stuff...>
}
<Style TargetType="src_general:Dialog">
<Setter Property="Padding" Value="25"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="src_general:Dialog">
<Grid x:Name="RootElement" >
<vsm:VisualStateManager.VisualStateGroups>
<vsm:VisualStateGroup x:Name="DiakogStyleStates">
<vsm:VisualState x:Name="OkCancel">
<Storyboard>
</Storyboard>
</vsm:VisualState>
<vsm:VisualState x:Name="OkOnly">
<Storyboard>
<ObjectAnimationUsingKeyFrames Duration="0:0:0" Storyboard.TargetName="CancelButton" Storyboard.TargetProperty="Visibility" >
<DiscreteObjectKeyFrame KeyTime="0:0:0" >
<DiscreteObjectKeyFrame.Value>
<Visibility>Collapsed</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
<vsm:VisualState x:Name="CancelOnly">
<Storyboard>
<ObjectAnimationUsingKeyFrames Duration="0:0:0" Storyboard.TargetName="OkButton" Storyboard.TargetProperty="Visibility" >
<DiscreteObjectKeyFrame KeyTime="0:0:0" >
<DiscreteObjectKeyFrame.Value>
<Visibility>Collapsed</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
<vsm:VisualState x:Name="None">
<Storyboard>
<ObjectAnimationUsingKeyFrames Duration="0:0:0" Storyboard.TargetName="CancelButton" Storyboard.TargetProperty="Visibility" >
<DiscreteObjectKeyFrame KeyTime="0:0:0" >
<DiscreteObjectKeyFrame.Value>
<Visibility>Collapsed</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Duration="0:0:0" Storyboard.TargetName="OkButton" Storyboard.TargetProperty="Visibility" >
<DiscreteObjectKeyFrame KeyTime="0:0:0" >
<DiscreteObjectKeyFrame.Value>
<Visibility>Collapsed</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
</vsm:VisualStateGroup>
</vsm:VisualStateManager.VisualStateGroups>
<Popup x:Name="DialogPopup">
<src_general:WindowFrame x:Name="Frame">
<Grid >
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ContentPresenter Grid.Row="0" x:Name="ContentPresenter" Margin="{TemplateBinding Padding}"/>
<!--Action Buttons-->
<StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Right" Margin="15">
<src_general:GlassButton x:Name="CancelButton" Content="Cancel" Margin="2"/>
<src_general:GlassButton x:Name="OkButton" Content="Ok" Margin="2"/>
</StackPanel>
</Grid>
</src_general:WindowFrame>
</Popup>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
我在很多地方使用这个对话框都没有问题。但是,在一个应用程序中,从RootVisual嵌套了大约3-4个usercontrols,我使用它的方式如下:
<general:Dialog x:Name="AddUpdateDialog" DialogStyle="OkCancel" Title="Add/Update Connection" Closed="AddUpdateDialog_Closed" ValidationGroup="AddConnection">
<Grid Width="300">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="10"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="Name:" Style="{StaticResource LabelText}"/>
<TextBox Grid.Row="0" Grid.Column="2" Text="{Binding Name, Mode=TwoWay}" Style="{StaticResource TextBoxInput}" MaxLength="49">
<val:ValidationManager.Validator>
<val:RequiredValidator ManagerName="AddConnection" ErrorMessage="Name is required."/>
</val:ValidationManager.Validator>
</TextBox>
</Grid>
</general:Dialog>
当我运行此应用程序时,我会间歇性(大约每5-10次启动)出现以下异常:
“无法强制转换类型为的对象
System.Windows.Controls.ContentControl
hookitupright.com.silverlight.controls.general.Dialog
“发生在
InitializeComponent()
为父母
UserControl
对上述XAML的定义。
this.AddUpdateDialog = ((hookitupright.com.silverlight.controls.general.Dialog)(this.FindName("AddUpdateDialog")));
当我在那里放置断点时,大多数时候FindName返回对话框类型的对象,但有时返回ContentControl(对话框的基础)并失败。XAML没有改变。它是静态的…因为异常是间歇性的,并且发生在生成的代码中,所以我不知所措。
我试过:
-
-
2a。考虑到这可能与文本框的双向绑定有关,我删除了绑定。仍然失败。
更新:鉴于以上第(2)条,我把文本框注释掉了,决定继续讨论其他事情,并带着希望回到这个话题,希望有什么事情会向我展示自己。不幸的是,它似乎在文本框关闭时也会失败,只是频率较低。
问题是它并非每次都失败。大约有20%的时间会爆炸。当它工作时,所有的东西都能工作,即使是这个对话框?
如果不是同一个问题的话,这个问题是相关的:当我通过注释掉所需的功能来“修复”invalidcast时,我将不太频繁地但间歇性地得到它
this
无效的属性(当属性/属性实际存在时)。
