IValueConverter and ValidationRule : Validation « Windows Presentation Foundation « C# / C Sharp






IValueConverter and ValidationRule

IValueConverter and ValidationRule
  
<Window x:Class="WpfApplication1.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:sys="clr-namespace:System;assembly=mscorlib"
  xmlns:local="clr-namespace:WpfApplication1" 
  Title="Random Numbers Built to Order">

  <Window.Resources>
    <ObjectDataProvider x:Key="nextRandomNumber" ObjectType="{x:Type sys:Random}"  MethodName="Next">
      <ObjectDataProvider.MethodParameters>
        <sys:Int32>0</sys:Int32>
        <sys:Int32>10</sys:Int32>
      </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
    <local:StringToInt32Converter x:Key="numConverter" />
  </Window.Resources>

  <StackPanel DataContext="{StaticResource nextRandomNumber}">
    <Label>Min</Label>
    <TextBox Name="minTextBox" ToolTip="{Binding ElementName=minTextBox, Path=(Validation.Errors)[0].ErrorContent}">
      <TextBox.Text>
        <Binding Path="MethodParameters[0]" BindsDirectlyToSource="True" Converter="{StaticResource numConverter}">
          <Binding.ValidationRules>
            <local:IntegerValidator />
          </Binding.ValidationRules>
        </Binding>
      </TextBox.Text>
    </TextBox>
    <Label>Max</Label>
    <TextBox Name="maxTextBox" ToolTip="{Binding ElementName=maxTextBox, Path=(Validation.Errors)[0].ErrorContent}">
      <TextBox.Text>
        <Binding Path="MethodParameters[1]" BindsDirectlyToSource="True" Converter="{StaticResource numConverter}">
          <Binding.ValidationRules>
            <local:IntegerValidator />
          </Binding.ValidationRules>
        </Binding>
      </TextBox.Text>
    </TextBox>
    <Label>Random</Label>
    <TextBox Text="{Binding Mode=OneTime}" IsReadOnly="True" />
    <Button Name="nextButton">Next</Button>
  </StackPanel>
</Window>
//File:Window.xaml.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace WpfApplication1 {
  public partial class Window1 : System.Windows.Window {

    public Window1() {
      InitializeComponent();
      nextButton.Click += new RoutedEventHandler(nextButton_Click);
    }

    void nextButton_Click(object sender, RoutedEventArgs e) {
      ((ObjectDataProvider)Resources["nextRandomNumber"]).Refresh();
    }

  }

  public class StringToInt32Converter : IValueConverter {
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
      return ((int)value).ToString();
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
      return int.Parse((string)value);
    }
  }

  public class IntegerValidator : ValidationRule {
    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo) {
      try {
        int.Parse((string)value);
        return ValidationResult.ValidResult;
      }
      catch( Exception ex ) {
        return new ValidationResult(false, ex.Message);
      }
    }
  }
}

   
    
  








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