WPF的转换器中使用Brush应注意问题
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WPF的转换器中使用Brush应注意问题
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1、Brushes用錯了命名空間將導致程序無法正確工作。筆者曾寫了一個flag值轉換為相應的Brush,由于不小心Using了一個錯誤的命名空間(System.Drawing)導致Xaml文件界面元素Fill綁定屬性總出不來應有的效果。最后費了好大勁才發現,替換為正確的命名空間(System.Windows.Media)后立馬就解決了。特此留下隨筆備忘。
2、下面是一個IMultiValueConverter的例子:
<Window x:Class="WpfApplication16.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:my="clr-namespace:WpfApplication16" Title="Window1" Height="300" Width="300"> <Window.Resources> <my:RgbConverter x:Key="RgbConverter" /> </Window.Resources> <Window.Background> <SolidColorBrush> <SolidColorBrush.Color> <MultiBinding Converter="{StaticResource RgbConverter}"> <Binding Path="Value" ElementName="redSlider" /> <Binding Path="Value" ElementName="greenSlider" /> <Binding Path="Value" ElementName="blueSlider" /> </MultiBinding> </SolidColorBrush.Color> </SolidColorBrush> </Window.Background> <StackPanel> <Slider Minimum="0" Maximum="255" x:Name="redSlider" /> <Slider Minimum="0" Maximum="255" x:Name="greenSlider" /> <Slider Minimum="0" Maximum="255" x:Name="blueSlider" /> </StackPanel> </Window> public class RgbConverter : IMultiValueConverter { #region IMultiValueConverter Members public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture) { var r = System.Convert.ToByte(values[0]); var g = System.Convert.ToByte(values[1]); var b = System.Convert.ToByte(values[2]); return Color.FromRgb(r, g, b); } public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } #endregion }?3、多值參數如何處理,譬如:希望value為真時返回ConvertParameter指定R,G,B的顏色值Brush,否則返回透明Brush。
<Border Grid.ColumnSpan="3" BorderBrush="{Binding Converter={StaticResource BoolToSolidColorBrushConverter}, ConverterParameter='255,0,0', Path=IsInclusive}" BorderThickness="2"><Image Source="{Binding Image}" Opacity="{Binding ImageOpacity}" /> </Border> public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {Brush result = Brushes.Red;if (parameter != null){string[] rgb = parameter.ToString().Split(',');if (rgb.Length == 3){byte r = 0;byte.TryParse(rgb[0], out r);byte g = 0;byte.TryParse(rgb[1], out g);byte b = 0;byte.TryParse(rgb[2], out b);result = new SolidColorBrush(Color.FromRgb(r, g, b));}}if (value == null) return Brushes.Transparent;string valueString = value.ToString();if (value.ToString() == "1"){valueString = "True";}else if (value.ToString() == "0"){valueString = "False";}bool boolValue = false;if (!bool.TryParse(valueString, out boolValue)){boolValue = false;}if (boolValue) return result;return Brushes.Transparent; }?
轉載于:https://www.cnblogs.com/chriskwok/archive/2012/08/17/2644201.html
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