TemplateBinding 不适用于 ValidationRules 依赖属性 [英] TemplateBinding Not working on ValidationRules Dependency Property
本文介绍了TemplateBinding 不适用于 ValidationRules 依赖属性的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试制作 cutom 验证器控件，但不知道为什么我想要绑定到模板化父级的 ValidationRules 上的 Message 属性.它可以运行，但每次都是空的.不知道为什么每次都是空的.
I am trying to make cutom validator controls but dont know why the Message Property that i have on the ValidationRules that i wanted to bind to the templated parent. It works runs but everytime its empty. Dont know why its empty everytime.
可以找到示例项目这里
风格
<Style TargetType="{x:Type local:RequiredFieldBox}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:RequiredFieldBox}">
<StackPanel Orientation="Vertical">
<TextBox>
<Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Text">
<Binding.ValidationRules>
<rule:RequiredFieldRule>
<rule:RequiredFieldRule.Params>
<rule:ValidationParams
Message="{TemplateBinding Msg}"
ValidationType="{TemplateBinding Type}"/>
</rule:RequiredFieldRule.Params>
</rule:RequiredFieldRule>
</Binding.ValidationRules>
</Binding>
<TextBox.Style>
<Style TargetType="{x:Type TextBox}">
<Style.Triggers>
<Trigger Property="Validation.HasError" Value="true" >
<Setter Property="Foreground" Value="Red"/>
<Setter Property="Background" Value="MistyRose"/>
<Setter Property="BorderBrush" Value="Red"/>
<Setter Property="BorderThickness" Value="1.0"/>
<Setter Property="VerticalContentAlignment" Value="Center"/>
</Trigger>
</Style.Triggers>
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<StackPanel>
<StackPanel Orientation="Horizontal" VerticalAlignment="Top" Margin="40">
<AdornedElementPlaceholder x:Name="Holder"/>
<Image Height="{Binding Height, ElementName=Holder}" Width="20" Margin="10,0"
Source="/Images/restricted.png" ToolTip="{Binding ElementName=Holder,
Path=AdornedElement.(Validation.Errors)
[0].ErrorContent}"/>
</StackPanel>
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</TextBox.Style>
</TextBox>
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
验证参数类
public class ValidationParams : DependencyObject
{
public static readonly DependencyProperty MessageProperty = DependencyProperty.Register(
"Message",
typeof(string),
typeof(ValidationParams),
new FrameworkPropertyMetadata(null));
// Dependency Properties
public static readonly DependencyProperty ValidationTypeProperty = DependencyProperty.Register("ValidationType",
typeof(RequiredFieldRule.EnmValidationType),
typeof(ValidationParams),
new FrameworkPropertyMetadata(RequiredFieldRule.EnmValidationType.FieldNotEmpty));
public static readonly DependencyProperty FieldNameProperty = DependencyProperty.Register("FieldName",
typeof(string),
typeof(ValidationParams),
new FrameworkPropertyMetadata(string.Empty));
public string FieldName
{
get { return (string)GetValue(FieldNameProperty); }
set { SetValue(FieldNameProperty, value); }
}
// Properties
public string Message
{
get { return (string)GetValue(MessageProperty); }
set { SetValue(MessageProperty, value); }
}
[Category("ValidationType")]
public RequiredFieldRule.EnmValidationType ValidationType
{
get { return (RequiredFieldRule.EnmValidationType)GetValue(ValidationTypeProperty); }
set { SetValue(ValidationTypeProperty, value); }
}
}
自定义控件类
public class RequiredFieldBox : Control
{
static RequiredFieldBox()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(RequiredFieldBox), new FrameworkPropertyMetadata(typeof(RequiredFieldBox)));
}
public static readonly DependencyProperty MsgProperty = DependencyProperty.Register(
"Msg",
typeof(string),
typeof(RequiredFieldBox),
new FrameworkPropertyMetadata(null)
);
public enum EnmValidationType
{
FieldNotEmpty,
FieldNumeric,
FieldIPAddress
}
public static readonly DependencyProperty TypeProperty = DependencyProperty.Register("Type",
typeof(RequiredFieldBox.EnmValidationType),
typeof(RequiredFieldBox),
new FrameworkPropertyMetadata(RequiredFieldBox.EnmValidationType.FieldNotEmpty));
public EnmValidationType Type
{
get { return (EnmValidationType) GetValue(TypeProperty); }
set { SetValue(TypeProperty, value);}
}
private static void MessageChanaged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
RequiredFieldBox sh = (RequiredFieldBox)d;
if (sh.Msg != (string)e.OldValue)
sh.Msg = (string)e.NewValue;
}
public static readonly DependencyProperty TextProperty = DependencyProperty.Register(
"Text", //Property name
typeof( object ), //Property type
typeof( RequiredFieldBox ));
public string Msg
{
get { return (string)GetValue(MsgProperty); }
set { SetValue(MsgProperty, value); }
}
public object Text
{
get { return GetValue(TextProperty);}
set { SetValue(TextProperty, value); }
}
}
验证规则类
公共类 RequiredFieldRule : ValidationRule{
public class RequiredFieldRule : ValidationRule {
public enum EnmValidationType
{
FieldNotEmpty,
FieldNumeric,
FieldIPAddress
}
// Local variables and objects
private ValidationParams mParams = new ValidationParams();
public ValidationParams Params
{
get { return mParams; }
set { mParams = value;}
}
// Override
public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
{
ValidationResult objResult = null;
string sValue = value as string;
objResult = new ValidationResult(true, null);
switch (Params.ValidationType)
{
case EnmValidationType.FieldNotEmpty:
if (string.IsNullOrEmpty(sValue) == true)
return new ValidationResult(false, Params.Message);
break;
case EnmValidationType.FieldNumeric:
int iValue = 0;
if (int.TryParse(sValue, out iValue) == false)
objResult = new ValidationResult(false, Params.Message);
break;
case EnmValidationType.FieldIPAddress:
break;
}
return objResult;
}
}
推荐答案
在验证规则中没有上下文或树连接，因为模板绑定大致等同于 RelativeSource 绑定它不会工作.你可能不走运...
In a validation rule there is no context or tree connection, as a template binding is roughly equivalent to a RelativeSource binding it will not work. You might be out of luck...
通常唯一有效的是Source 结合 StaticResource，x:Reference 或 x:Static，因为您不能通过名称引用模板化父项，也许可以通过另一个控件隧道它，例如类似:
Usually the only thing that works is Source in combination with StaticResource, x:Reference or x:Static, as you cannot refer to the templated parent via name you maybe can tunnel it through another control, e.g. something like:
<TextBox x:Name="RequiredFieldBox"
Tag="{Binding RelativeSource={RelativeSource TemplatedParent}}">
<TextBox.Resources>
<rule:RequiredFieldRule x:Key="rule">
<rule:RequiredFieldRule.Params>
<rule:ValidationParams
Message="{Binding Tag.Msg, Source={x:Reference RequiredFieldBox}}"
ValidationType="{Binding Tag.Type, Source={x:Reference RequiredFieldBox}}"/>
</rule:RequiredFieldRule.Params>
</rule:RequiredFieldRule>
</TextBox.Resources>
<!-- ... --->
<Binding.ValidationRules>
<StaticResource ResourceKey="rule"/>
</Binding.ValidationRules>
(如果将 ValidationRule 留在原地，x:Reference 很可能会抱怨循环依赖)
(If the ValidationRule would be left in place the x:Reference in all likelihood would complain about cyclical dependency)
使用 StaticResource 和隧道元素的替代方法:
An alternative using StaticResource and a tunnel element:
<StackPanel Orientation="Vertical">
<StackPanel.Resources>
<FrameworkElement x:Key="Tunnel"
Tag="{Binding RelativeSource={RelativeSource AncestorType=local:RequiredFieldBox}}" />
</StackPanel.Resources>
<StaticResource ResourceKey="Tunnel" />
<TextBox x:Name="RequiredFieldBox">
<TextBox.Text>
<Binding RelativeSource="{RelativeSource TemplatedParent}" Path="Text">
<Binding.ValidationRules>
<rule:RequiredFieldRule>
<rule:RequiredFieldRule.Params>
<rule:ValidationParams
Message="{Binding Tag.Msg, Source={StaticResource Tunnel}}"
ValidationType="{Binding Tag.Type, Source={StaticResource Tunnel}}" />
</rule:RequiredFieldRule.Params>
</rule:RequiredFieldRule>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
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