禁用IDataErrorInfo中的按钮验证

问题描述：

我在我的视图模型上有两个命令，在我的View上有两个按钮“Search”和“Clear”。我在我的ViewModel上实现了IDataErrorInfo并验证了输入字段。我如何禁用“清除”按钮的验证？禁用IDataErrorInfo中的按钮验证

<TextBox Text="{Binding SearchText, Mode=TwoWay, ValidatesOnDataErrors=True, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 
Validation.ErrorTemplate="{StaticResource ErrorTemplate}"/> 
<Button Content="Search" Command="{Binding SearchCommand}" /> 
<Button Content="Clear" Command="{Binding ClearCommand}" />

你的要求不是更清晰。您是否希望根据Seach文本框中的文本禁用清除按钮。示例如果seach不为空或为空，请启用清除按钮。请解释 – 2015-02-08 22:04:25

答

我假设您想要启用/禁用基于搜索文本框中的验证的清除按钮。我已经使用MvvmLight继电器命令来使用命名空间使用GalaSoft.MvvmLight.CommandWpf命令从最新的MVVMLight;请参阅下面的代码。

<Window x:Class="DataTemplateSelector_Learning.Window3" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Title="Window3" Height="300" Width="300">  
<Grid> 
    <StackPanel> 
     <StackPanel Orientation="Horizontal"> 
      <TextBlock Text="Search Text"/> 
      <TextBox Width="100" Text="{Binding SearchText, UpdateSourceTrigger=PropertyChanged,Mode=TwoWay, 
       ValidatesOnDataErrors=True, NotifyOnValidationError=True, ValidatesOnExceptions=True}" /> 
     </StackPanel> 
     <Button Content="Search" Command="{Binding SearchCommand}" /> 
     <Button Content="Clear" Command="{Binding ClearCommand}" /> 
    </StackPanel> 
</Grid>

public partial class Window3 : Window 
{ 
    public Window3() 
    { 
     InitializeComponent(); 
     this.DataContext = new ViewModel(); 
    } 
} 
class ViewModel:INotifyPropertyChanged,IDataErrorInfo 
{ 
    private string searchText; 
    private bool enableClear; 

    public string SearchText 
    { 
     get { return searchText; } 
     set { searchText = value; Notify("SearchText"); } 
    } 

    public ICommand SearchCommand { get; set; } 
    public ICommand ClearCommand { get; set; } 

    public ViewModel() 
    { 
     ClearCommand = new RelayCommand(OnClear, CanClear); 
    } 

    private bool CanClear() 
    { 
     return enableClear; 
    } 

    private void OnClear() 
    { 

    } 

    public event PropertyChangedEventHandler PropertyChanged; 

    private void Notify(string propName) 
    { 
     if (PropertyChanged != null) 
     { 
      PropertyChanged(this, new PropertyChangedEventArgs(propName)); 
     }    

    } 

    public string Error 
    { 
     get { return String.Empty; } 
    } 

    public string this[string columnName] 
    { 
     get 
     { 
      String errorMessage = String.Empty; 
      if (!string.IsNullOrEmpty(SearchText)) 
      { 
       if (SearchText.Length > 0) 
       { 
        enableClear = true; 
       } 
       else 
       { 
        enableClear = false; 
       } 
      } 

      return errorMessage; 
     } 
    } 
}

禁用IDataErrorInfo中的按钮验证

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