WPF在有效性规则绑定属性 [英] wpf binding property in ValidationRule

问题描述

我遇到了两个文本框形式：

  

  

1. TotalLoginsTextBox


  

2. UploadsLoginsTextBox


  

我想限制UploadsLoginsTextBox这样的文本的最大输入将是TotalLoginsTextBox的值。
我还使用值转换器，所以我尝试绑定的最大值：

这是XAML：

 ＆LT;！ - 合计登录 - ＆GT;
＆LT;标签保证金=5个总：LT; /标签＆gt;
＆LT;文本框名称=TotalLoginsTextBox了minWidth =30文本={绑定路径= MAXLOGINS，模式=双向}/＆GT;
＆LT;！ - 上传 - ＆GT;
＆LT;标签保证金=5＆GT;上传：LT; /标签＆gt;
＆所述;文本框名称=UploadsLoginsTextBox了minWidth =30＆GT;
    ＆LT; TextBox.Text＆GT;
        ＆LT;绑定路径=MAXUP模式=双向NotifyOnValidationError =真＆GT;
            ＆LT; Binding.ValidationRules＆GT;
                ＆LT;校验：MinMaxRangeValidatorRule最小=0最大={绑定路径= MAXLOGINS}/＆GT;
            ＆LT; /Binding.ValidationRules>
        ＆LT; /装订＆GT;
    ＆LT; /TextBox.Text>
＆LT; /文本框＆GT;
 

问题我收到以下错误：

  

一个绑定不能在类型的'最大'属性设置
  MinMaxRangeValidatorRule。 A'绑定'只能在一组
  的DependencyProperty DependencyObject的。

什么是做绑定的正确方法？

解决方案

您会看到这个错误的原因的 MinMaxRangeValidatorRule.Maximum 的需要是一个的DependencyProperty，如果你想将其绑定到的 MAXLOGINS 的，虽然它可能是一个简单的CLR属性。

真正的问题是，MinMaxRangeValidatorRule应该能够从有效性规则和自DependencyObject（使依赖属性可用）继承。这是不可能的在C＃

我解决这样一个类似的问题：

1. 提供一个名称的验证规则

    ＆LT;校验：MinMaxRangeValidatorRule NAME =MinMaxValidator最小=0/＆GT;
    




2. 在code的背后，设置最大值时MAXLOGINS变化

    公众诠释MAXLOGINS
   {
       {返回（INT）的GetValue（MaxLoginsProperty）; }
       集合{的SetValue（MaxLoginsProperty，值）; }
   }
   公共静态的DependencyProperty MaxLoginsProperty = DependencyProperty.Register（MAXLOGINS
                                                                                       typeof运算（INT）
                                                                                       typeof运算（mycontrol）
                                                                                       新PropertyMetadata（HandleMaxLoginsChanged））;私有静态无效HandleMinValueChanged（DependencyObject的D，DependencyPropertyChangedEventArgs E）
   {
       mycontrol源=（mycontrol）D;
       source.MinMaxValidator.Maximum =（INT）e.NewValue;
   }
    

i'm having a form with 2 text boxes:

1. TotalLoginsTextBox

2. UploadsLoginsTextBox

i want to limit UploadsLoginsTextBox so the maximum input for the text will be the value of the TotalLoginsTextBox. i am also using a value converter so i try to bound the Maximum value:

this is the XAML:

<!-- Total Logins -->
<Label Margin="5">Total:</Label>
<TextBox Name="TotalLoginsTextBox" MinWidth="30" Text="{Binding Path=MaxLogins, Mode=TwoWay}" />
<!-- Uploads -->
<Label Margin="5">Uploads:</Label>
<TextBox Name="UploadsLoginsTextBox" MinWidth="30">
    <TextBox.Text>
        <Binding Path="MaxUp" Mode="TwoWay" NotifyOnValidationError="True">
            <Binding.ValidationRules>
                <Validators:MinMaxRangeValidatorRule Minimum="0" Maximum="{Binding Path=MaxLogins}" />
            </Binding.ValidationRules>
        </Binding>
    </TextBox.Text>
</TextBox>

the problem i am getting the following error:

A 'Binding' cannot be set on the 'Maximum' property of type 'MinMaxRangeValidatorRule'. A 'Binding' can only be set on a DependencyProperty of a DependencyObject.

what is the proper way to do the binding ?

解决方案

You're seeing this error because MinMaxRangeValidatorRule.Maximum needs to be a DependencyProperty if you want to bind it to MaxLogins, while it is probably a simple CLR property.

The real problem is that MinMaxRangeValidatorRule should be able to inherit from ValidationRule AND from DependencyObject (to make Dependency Properties available). This is not possible in C#.

I solved a similar problem in this way:

1. give a name to your validator rule

   <Validators:MinMaxRangeValidatorRule Name="MinMaxValidator" Minimum="0" />
   

2. in code behind, set the Maximum value whenever MaxLogins changes

   public int MaxLogins 
   {
       get { return (int )GetValue(MaxLoginsProperty); }
       set { SetValue(MaxLoginsProperty, value); }
   }
   public static DependencyProperty MaxLoginsProperty = DependencyProperty.Register("MaxLogins ", 
                                                                                       typeof(int), 
                                                                                       typeof(mycontrol), 
                                                                                       new PropertyMetadata(HandleMaxLoginsChanged));
   
   private static void HandleMinValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
   {
       mycontrol source = (mycontrol) d;
       source.MinMaxValidator.Maximum = (int) e.NewValue;
   }
   

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