wpf 相关问题

Windows Presentation Foundation或WPF是用于在基于Windows的应用程序中呈现用户界面的子系统。

我正在尝试将商品计数圆圈放置在购物车图标上。当我设置边距来调整项目圆圈时，它会开箱即用。见下图：这是带有

wpf xaml button margin ellipse

回答 1 投票 0

我有一个简单的组合框模板，其结构如下：我有一个以这种方式构造的组合框的简单模板： <ComboBox DockPanel.Dock="Left" MinWidth="100" MaxHeight="24" ItemsSource="{Binding Actions}"> <ComboBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Name}" Width="100" /> <Image Source="{Binding Converter={StaticResource TypeConverter}}" /> </StackPanel> </DataTemplate> </ComboBox.ItemTemplate> </ComboBox> 所以，如果我使用这段代码，一切都会正常： <TextBlock Text="{Binding Name}" Width="100" />  <Image Source="{StaticResource SecurityImage}" /> 但是如果我使用转换器，它就不再起作用了。这是转换器，但我不知道如何从那里引用静态资源... public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { var type = (Action)value; var img = new BitmapImage(); switch (type.ActionType) { case ActionType.Security: img.UriSource = new Uri("StructureImage", UriKind.Relative); break; case ActionType.Structural: img.UriSource = new Uri("SecurityImage", UriKind.Relative); break; } return img; } 尝试使用 Josh 编写的 Switch Converter，应该对你有用： SwitchConverter – XAML 的“switch 语句”- http://josheinstein.com/blog/index.php/2010/06/switchconverter-a-switch-statement-for-xaml/ 无需编写转换器，您的代码将如下所示 - <Grid.Resources> <e:SwitchConverter x:Key="ActionIcons"> <e:SwitchCase When="Security" Then="SecurithImage.png" /> <e:SwitchCase When="Structural" Then="StructureImage.png" /> </e:SwitchConverter> </Grid.Resources> <Image Source="{Binding Converter={StaticResource ActionIcons}}" /> 更新1：这是 SwitchConverter 的代码，因为 Josh 的网站似乎已关闭 - /// <summary> /// A converter that accepts <see cref="SwitchConverterCase"/>s and converts them to the /// Then property of the case. /// </summary> [ContentProperty("Cases")] public class SwitchConverter : IValueConverter { // Converter instances. List<SwitchConverterCase> _cases; #region Public Properties. /// <summary> /// Gets or sets an array of <see cref="SwitchConverterCase"/>s that this converter can use to produde values from. /// </summary> public List<SwitchConverterCase> Cases { get { return _cases; } set { _cases = value; } } #endregion #region Construction. /// <summary> /// Initializes a new instance of the <see cref="SwitchConverter"/> class. /// </summary> public SwitchConverter() { // Create the cases array. _cases = new List<SwitchConverterCase>(); } #endregion /// <summary> /// Converts a value. /// </summary> /// <param name="value">The value produced by the binding source.</param> /// <param name="targetType">The type of the binding target property.</param> /// <param name="parameter">The converter parameter to use.</param> /// <param name="culture">The culture to use in the converter.</param> /// <returns> /// A converted value. If the method returns null, the valid null value is used. /// </returns> public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { // This will be the results of the operation. object results = null; // I'm only willing to convert SwitchConverterCases in this converter and no nulls! if (value == null) throw new ArgumentNullException("value"); // I need to find out if the case that matches this value actually exists in this converters cases collection. if (_cases != null && _cases.Count > 0) for (int i = 0; i < _cases.Count; i++) { // Get a reference to this case. SwitchConverterCase targetCase = _cases[i]; // Check to see if the value is the cases When parameter. if (value == targetCase || value.ToString().ToUpper() == targetCase.When.ToString().ToUpper()) { // We've got what we want, the results can now be set to the Then property // of the case we're on. results = targetCase.Then; // All done, get out of the loop. break; } } // return the results. return results; } /// <summary> /// Converts a value. /// </summary> /// <param name="value">The value that is produced by the binding target.</param> /// <param name="targetType">The type to convert to.</param> /// <param name="parameter">The converter parameter to use.</param> /// <param name="culture">The culture to use in the converter.</param> /// <returns> /// A converted value. If the method returns null, the valid null value is used. /// </returns> public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } } /// <summary> /// Represents a case for a switch converter. /// </summary> [ContentProperty("Then")] public class SwitchConverterCase { // case instances. string _when; object _then; #region Public Properties. /// <summary> /// Gets or sets the condition of the case. /// </summary> public string When { get { return _when; } set { _when = value; } } /// <summary> /// Gets or sets the results of this case when run through a <see cref="SwitchConverter"/> /// </summary> public object Then { get { return _then; } set { _then = value; } } #endregion #region Construction. /// <summary> /// Switches the converter. /// </summary> public SwitchConverterCase() { } /// <summary> /// Initializes a new instance of the <see cref="SwitchConverterCase"/> class. /// </summary> /// <param name="when">The condition of the case.</param> /// <param name="then">The results of this case when run through a <see cref="SwitchConverter"/>.</param> public SwitchConverterCase(string when, object then) { // Hook up the instances. this._then = then; this._when = when; } #endregion /// <summary> /// Returns a <see cref="System.String"/> that represents this instance. /// </summary> /// <returns> /// A <see cref="System.String"/> that represents this instance. /// </returns> public override string ToString() { return string.Format("When={0}; Then={1}", When.ToString(), Then.ToString()); } } 更新2：来自 Microsoft 参考源的另一个 SwitchConverter 实现。使用Image.UriSource时，如果图像已添加到您的项目中并且其“构建操作”已设置为“资源”，则需要指定图像的相对文件路径。例如。如果您已将图像放在 Visual Studio 中名为“images”的项目文件夹中，则可以通过以下方式引用图像： img.UriSource = new Uri("/Images/StructureImage.png", UriKind.Relative); 如果图像未构建为资源，则必须使用完整文件路径，即 img.UriSource = new Uri("http://server/Images/StructureImage.png", UriKind.Absolute); 编辑：如果您将图像放入应用程序资源字典中，您始终可以通过以下方式访问它： Application.Current.Resources["StructureImage"]; 如果您将资源放在其他地方，您可以使用 IMultiValueConverter 而不是 IValueConverter 作为转换器。那么你的类型转换器将如下所示： class TestValueConverter : IMultiValueConverter { #region IMultiValueConverter Members public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture) { // Validation of parameters goes here... var type = (Action) values[0]; var image1 = values[1]; var image2 = values[2]; if (type.ActionType == ActionType.Security) { return image1; } else { return image2; } } public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } #endregion } 您的 XAML 看起来与此类似： <Image> <Image.Source> <MultiBinding Converter="{StaticResource testValueConverter}"> <Binding Path="Action" /> <Binding Source="{StaticResource SecurityImage}" /> <Binding Source="{StaticResource StructureImage}" /> </MultiBinding> </Image.Source> </Image> 最后，这就是您定义资源的方式： <imaging:BitmapImage x:Key="StructureImage" UriSource="StructureImage.png" /> <imaging:BitmapImage x:Key="SecurityImage" UriSource="SecurityImage.png" /> <local:TestValueConverter x:Key="testValueConverter" /> 以上代码未经测试！虽然接受的答案很好，但我通常会避免“组合框”中带有图像的转换器的复杂性。我通常将图像源 (uri) 的数据类型定义为字符串。这样，就不需要转换器了。下面是一个分步示例：第1步：创建语言对象类 public class Language { public int Id { get; set; } public string Code { get; set; } = string.Empty; public string Name { get; set; } = string.Empty; public string Uri { get; set; } = string.Empty; } 第 2 步：在视图模型或隐藏代码中创建语言对象的数组 public class ExampleViewModel { private ObservableCollection<Language>? _languages; public IEnumerable<Language>? Languages => _languages; public ExampleViewModel() { string baseUri = "pack://application:,,,/;component/Images"; // The following static data can also come from the database _languages = [ new() { Id = 2, Code = "en-GB", Name = "English", Uri = $"{baseUri}/gb.png" }, new() { Id = 1, Code = "de-DE", Name = "German", Uri = $"{baseUri}/de.png" } ]; } } 第3步：在视图中创建组合框 XAML: <ComboBox x:Name="cbxLanguageSelection" Margin="0,0,0,0" HorizontalAlignment="Left" Background="Transparent" BorderThickness="0" ItemsSource="{Binding Languages}" SelectedItem="{Binding SelectedLanguage, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Style="{StaticResource ResourceKey=ComboBoxStyle}" ToolTip="Language Selection" Visibility="Visible"> <ComboBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal" Style="{StaticResource ResourceKey=DropDownStyle}"> <Image Height="18" Margin="0,0,5,0" Source="{Binding Path=Uri}" /> <TextBlock Text="{Binding Path=Name}" /> </StackPanel> </DataTemplate> </ComboBox.ItemTemplate> </ComboBox> *）请注意，样式和“SelectedLanguage”是可选的。 “SelectedLanguage”属性应在实现时在视图模型或代码隐藏中创建。

c# .net wpf converters resourcedictionary

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WPF - 适合嵌套网格的控件大小

使用 WPF，我的布局是一系列嵌套网格，因为我的理解是，这比使用 RowSpan 更能保留我想要的外观。每个生成的网格部分都是一个区域，

wpf xaml wpf-controls wpf-grid

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在 DependencyProperty 的 CoerceValueCallback 中取消更新时如何更新绑定的源？

我有一个控件（在下面的示例中名为 GridView）和一个视图模型，它们通过其 SelectedValue 属性上的 2 路绑定进行绑定。我想禁止

wpf mvvm binding

回答 2 投票 0

WPF DataGrid 上下文菜单无需右键单击该行即可显示

WPF 应用程序有 2 种模式：基本模式和高级模式。有一个数据网格，用户可以使用上下文菜单重新运行或删除当前项目。此上下文菜单仅在高级模式为