WPF组合框验证 [英] WPF Combobox validation

问题描述

我有一个ComboBox with Sex（男性，女性..）：我要求用户选择一个值（ComboBox默认没有值。）

 < ComboBox ItemsSource ={x：Static Member = data：Sex.AllTypes}SelectedItem ={Binding Path = Sex.Value，ValidatesOnDataErrors = True，UpdateSourceTrigger = PropertyChanged，NotifyOnValidationError = True}VerticalAlignment =Top> 
< ComboBox.ItemTemplate> 
< DataTemplate> 
< StackPanel Orientation =Horizo​​ntal> 
< TextBlock Text ={Binding Path = Name}/> 
< / StackPanel> 
< / DataTemplate> 
< /ComboBox.ItemTemplate> 
< / ComboBox> 
  

Sex.Value是我的Person类中的属性：

  public class Person：IDataErrorInfo 
 {
 public string this [string columnName] 
 {
 get 
 
 switch（columnName）
 {
 caseSex：return Sex.Value == null？ 必填字段：null; 
 caseSurname：return string.IsNullOrEmpty（Nachname）？ 必填字段：null; 
} 
} 
} 
 public string错误
 {
 get 
 {
 return null; 
} 
} 
} 
  

问题是输入这个[string columnname]。

当我尝试一个带有名称的TextBox时，它输入这个[string columnname]，一切正常：

< TextBox Style ={StaticResource textBoxInError}Text ={Binding Path = Surname，ValidatesOnDataErrors = True，UpdateSourceTrigger = PropertyChanged，NotifyOnValidationError = True} >


解决方案

Windows中的好方法是添加一个值无）到组合框中，并测试该人是否包含（无）值。 （无）是一个元选项，因为它不是选择的有效值，而是描述了选项本身没有被使用。

正确：

不正确：

验证不适用于您的情况，因为当您想说没有选择性别时没有选择值...

I have a ComboBox with Sex(male, female..):And I demand from user to select a value (the ComboBox has no value by default.)

<ComboBox ItemsSource="{x:Static Member=data:Sex.AllTypes}" SelectedItem="{Binding Path=Sex.Value, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged, NotifyOnValidationError=True}"  VerticalAlignment="Top">
        <ComboBox.ItemTemplate>
             <DataTemplate>
                  <StackPanel Orientation="Horizontal">
                      <TextBlock Text="{Binding Path=Name}" />
                  </StackPanel>
             </DataTemplate>
        </ComboBox.ItemTemplate>
</ComboBox>

Sex.Value is a Property in my Person class:

public class Person : IDataErrorInfo 
{
public string this[string columnName]
        {
            get
            {                
                switch (columnName)
                {                   
                    case "Sex": return Sex.Value == null ? "Required field" : null;
                    case "Surname": return string.IsNullOrEmpty(Nachname) ? "Required field" : null;
                }                
            }
        }
 public string Error
        {
            get
            {
                return null;
            }
        }
}

the problem is that it never enters this[string columnname].

When i try a TextBox with name, it enters this[string columnname] and everything works fine:

<TextBox  Style="{StaticResource textBoxInError}"   Text="{Binding Path=Surname, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged, NotifyOnValidationError=True}"/>

解决方案

The good way in windows is to add a value (None) into the combobox and test if the person contains the (None) value. "(None)" is a meta-option because it is not a valid value for the choice—rather it describes that the option itself isn't being used.

Correct:

Incorrect:

The validation doesn't work in your case because no value is selected when you want to say that no sex is selected...

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