WPF在有效性规则绑定属性

本文介绍了WPF在有效性规则绑定属性的处理方法，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

我遇到了两个文本框形式：

    

TotalLoginsTextBox

  

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：

提供一个名称的验证规则

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

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:

TotalLoginsTextBox

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:

give a name to your validator rule

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

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; }