Range converter for WPF
A member on the MSDN forums asked how to enable a button based on the index of the currently selected item in a ListBox. If the index was 0, they wanted the Button to be disabled. I whipped up a Converter:
[ValueConversion(typeof(int), typeof(bool))] public class IntToBooleanRangeConverter : IValueConverter { public object Convert(object value, Type targetType,
object parameter, System.Globalization.CultureInfo culture) { string range = parameter as string; int intVal = (int) value; if (!string.IsNullOrEmpty(range)) { string[] nums = range.Split(new char[] { '-' }); int[] checkVal = new int[nums.Length]; for(int i = 0; i < nums.Length; i ++) { int.TryParse(nums[i], out checkVal[i]); }if (nums.Length == 1)
{
return checkVal[0] == intVal;
}
else if (nums.Length == 2)
{
// is it #-# or #-?
if (!string.IsNullOrEmpty(nums[1]))
{
// # - #
return (intVal >= checkVal[0] && intVal <= checkVal[1]);
}
else
{
// #-
return intVal >= checkVal[0];
}
}
else
{
throw new ArgumentOutOfRangeException("IntToBooleanRangeConverter:
Range must be in format #-#, #-, or #");
}
}
throw new ArgumentOutOfRangeException("IntToBooleanRangeConverter:
Range must be in format #-#, #-, or #");
}public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return null;
}}
Here's a demo:
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WiredPrairieNamespace"
xmlns:System="clr-namespace:System;assembly=mscorlib"
x:Class="WiredPrairieNamespace.Window1"
x:Name="Window"
Title="Window1"
Width="640" Height="480">
<Window.Resources>
<local:IntToBooleanRangeConverter x:Key="IntToBooleanRangeConverter" />
</Window.Resources>
<Grid x:Name="LayoutRoot">
<ListBox HorizontalAlignment="Left" Margin="79,72,0,149" Width="191"
IsSynchronizedWithCurrentItem="True" x:Name="myList">
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
<ListBoxItem>Item</ListBoxItem>
</ListBox>
<Button IsEnabled="{Binding Path=SelectedIndex,
Converter={StaticResource IntToBooleanRangeConverter},
ConverterParameter=1-, ElementName=myList}"
HorizontalAlignment="Right" Margin="0,218,181,175"
Width="115" Content="Button" />
</Grid>
</Window>
