WPF
使用 SVG
-
通过 SvgToXaml 工具 将 SVG 图片转为 xaml 资源
-
打开工具，在底部选择 SVG 图片
- 在弹出的窗口中，切换到 XAML 查看代码
- 集成到资源字典，接下来我们可以把转换得到了xaml 集成到资源字典中，以下是直接放在
App.xaml中（可创建一个资源文件来存放）：
<Application x:Class="WpfApp3.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApp3"
StartupUri="MainWindow.xaml">
<Application.Resources>
<DrawingImage x:Key="XX">
<DrawingImage.Drawing>
<DrawingGroup ClipGeometry="M0,0 V25 H120 V0 H0 Z">
<GeometryDrawing Brush="#FFFFFFFF" Geometry="F1 M120,25z M0,0z M0,25L120,25 120,0 0,0 0,25z" />
<DrawingGroup Opacity="1">
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</DrawingGroup>
</DrawingGroup>
</DrawingImage.Drawing>
</DrawingImage>
</Application.Resources>
</Application>
- 前端使用，实现 TextBox 的水印功能（最好定义一个 image 的资源）
<Window x:Class="WpfApp3.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp3"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.Resources>
<ImageBrush x:Key="watermark" ImageSource="{StaticResource XX}" AlignmentX="Center" Stretch="None" />
</Window.Resources>
<StackPanel>
<TextBox Name="myTextBox" TextChanged="OnTextBoxTextChanged" Width="200" Height="25" Background="{StaticResource watermark}" />
</StackPanel>
</Window>
后端添加文本changed处理事件
private void OnTextBoxTextChanged(object sender, TextChangedEventArgs e)
{
if (sender is TextBox box)
{
if (string.IsNullOrEmpty(box.Text))
box.Background = (ImageBrush)FindResource("watermark");
else
box.Background = null;
}
}
剪切板错误
❌ WPF剪切板问题-OpenClipboard HRESULT:0x800401D0 (CLIPBRD_E_CANT_OPEN))
错误示例：
原实现：
Clipboard.SetText(content);
解决方法：
Clipboard.SetDataObject(content);
参考（其中的处理方式不优）
WPF剪切板问题-OpenClipboard HRESULT:0x800401D0 (CLIPBRD_E_CANT_OPEN))
元素焦点问题
Focus() 函数常常设置失败
通过以下方式可设置成功 pwdBoxPWD 需要设置的UI元素
Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Render,
new Action(() => pwdBoxPWD.Focus()));
WPF hardware acceleration in RDP
在 .net 8.0 后出现的问题
调试模式正常运行，发布后无法运行，提示设置硬件加速
解决方案：
在项目中配置此设置RuntimeHostConfigurationOption：
<Project Sdk="Microsoft.NET.Sdk">
<ItemGroup>
<RuntimeHostConfigurationOption Include="Switch.System.Windows.Media.EnableHardwareAccelerationInRdp" Value="true" />
</ItemGroup>
</Project>
删除所有的文件，再生成
项目示例：
在某项目中，有一组菜单按钮，一个菜单对应一个页面，假设A按钮对应A页面，B按钮对应B页面，同时有个需求，在A页面，按下空格键后代码控制跳转到B页面。
出现问题：当点击A按钮后，然后按下空格键，不会跳到B页面。
调试结果：按下空格键后执行代码跳转到B页面后，会再次跳转到A页面。
分析原因：
- 点击A按钮，此时A按钮获得键盘焦点。
- 按下空格键，执行跳转到B的代码逻辑，跳转到B页面。
- 执行完成后，由于A按钮具有焦点会响应键盘，所以会执行A按钮的点击事件，既点击了A按钮，跳转到A页面。
Label 控件格式化
单独使用 ContentStringFormat
格式化日期
<Label Width="100" Height="30" Content="{Binding Path=DateTime.Now}" ContentStringFormat='{}{0:yyyy-MM-dd}'></Label>
格式化时间
<Label Width="100" Height="30" Content="{Binding Path=DateTime.Now}" ContentStringFormat='{}{0:hh:mm:ss}'></Label>
上下文菜单
在资源文件中定义菜单内容
在资源文件中绑定上下文
（1）定义菜单绑定的上下文 MenuViewModel.cs
namespace MenuDemo
{
/// <summary>
/// 菜单绑定上下文
/// </summary>
public class MenuData
{
//这里可改为通知属性
public string Name{get;set;} = "Name01";
public string ItemName{get;set;}= "Item01";
}
}
（2）定义页面绑定的上下文 MainWindowViewModel.cs
namespace MenuDemo
{
/// <summary>
/// 菜单绑定上下文
/// </summary>
public class MainWindowViewModel
{
//这里可改为通知属性
public MenuData Menu{get;set;} = new MenuData();
}
}
（3）定义菜单资源文件方式一（每项都指定对象Menu）：，路径： MenuViews.xaml
⚠️ 这里固定了 属性名称必须为Menu ，要解决参照: 使用附加属性绑定菜单的上下文
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ContextMenu x:Key="_menu">
<MenuItem Header="{Binding Menu.Name}" />
<Separator />
<MenuItem Header="{Binding Menu.ItemName}" />
</ContextMenu>
</ResourceDictionary>
（4）定义菜单资源文件方式二（在根节点上指定 Menu）：，路径： MenuViews.xaml
DataContext="{Binding RelativeSource={RelativeSource Self}, Path=PlacementTarget.DataContext.Menu}"
因为 ContextMenu 不直接属于视觉树里面的元素，所以要特殊处理
不能这样 DataContext="{Binding Menu}"
⚠️ 这里固定了 属性名称必须为Menu，要解决参照: 使用附加属性绑定菜单的上下文
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ContextMenu x:Key="_menu" DataContext="{Binding RelativeSource={RelativeSource Self}, Path=PlacementTarget.DataContext.Menu}">
<MenuItem Header="{Binding Name}" />
<Separator />
<MenuItem Header="{Binding ItemName}" />
</ContextMenu>
</ResourceDictionary>
(5) MainWindow.xaml
<Window x:Class="MenuDemo.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:MenuDemo"
xmlns:prism="http://prismlibrary.com/" >
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/MenuDemo;component/MenuViews.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>
<Grid Margin="12">
<Button ContextMenu="{StaticResource _menu}" >
</Button>
</Grid>
</Window>
(6) MainWindow.cs
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainWindowViewModel();
}
}
控制菜单的显示隐藏
需求描述
可禁止和激活菜单功能（即控制显示和不显示）
知识点
- 不要使用
Visibility来实现，因为右键的时都会创建PopupRoot, 由于未显示，他们不会触发失去焦点，不会自动关闭，所以右键多个对象后，都会创建 PopupRoot,若此时激活菜单，那么界面上会出现很多菜单 - 使用
ContextMenuOpening来控制，- 若上下文菜单直接在 UserControl 或者 Windows 中定义，那么可直接添加
ContextMenuOpening的处理事件 - 若菜单的条目在一个资源中定义，可使用一个静态变量来进行绑定，本节主要介绍这种方式。
- 若上下文菜单直接在 UserControl 或者 Windows 中定义，那么可直接添加
控制菜单 Active 的静态脚本 ContextMenuHelper
namespace MenuDemo
{
/// <summary>
/// 上下文菜单帮助类
/// </summary>
public static class ContextMenuHelper
{
//菜单状态
private static bool _menuActiveState;
/// <summary>
/// 提供此静态属性给 前端 ContextMenuOpening 进行绑定，不能直接绑定函数 ContextMenuOpeningHandler
/// 使用案例
/// 根节点引入命名空间： xmlns:local="clr-namespace:MenuDemo;assembly=MenuDemo"
/// 在需要上下文菜单的元素节点使用 ContextMenuOpening="{x:Static local:ContextMenuHelper.ContextMenuOpeningHandler}"
/// </summary>
public static ContextMenuEventHandler ContextMenuOpening
{
get; internal set;
}
static ContextMenuHelper()
{
ContextMenuOpening = ContextMenuOpeningHandler;
}
//切换菜单功能，更新状态
public static void SwitchActive(bool active)
{
_menuActiveState = active;
}
private static void ContextMenuOpeningHandler(object sender, ContextMenuEventArgs e)
{
e.Handled = !_menuActiveState;//根据变量判断是否取消事件。 _menuActiveState：false 时 e.Handled = true 表示取消
}
}
}
前端绑定,注意在根目录引入：xmlns:local="clr-namespace:MenuDemo;assembly=MenuDemo"
<Button ContextMenu="{StaticResource _menu}"
ContextMenuOpening="{x:Static local:ContextMenuHelper.ContextMenuOpening}">
</Button>
无法引用静态资源同时绑定上下文
这样能使用资源，但是无法绑定上下文
<Button DataContext="{Binding PlatformDemo}"
ContextMenu="{StaticResource zt}" >
<!--没有提供 ContextMenu.DataContext-->
</Button>
这样能绑定上下文，但是无法使用资源
<Button>
<Button.ContextMenu>
<ContextMenu DataContext="{Binding RelativeSource={RelativeSource Self}, Path=PlacementTarget.DataContext.Menu}">
<!--只能在这里添加item 或者 绑定 ItemSources(推荐)-->
</ContextMenu>
</Button.ContextMenu>
</Button>
通过嵌套元素来绑定菜单的上下文
前面章节存在下面问题
⚠️ 这里固定了 属性名称必须为Menu
下面通过嵌套来处理这个问题，把菜单放在 Button 的子元素，如下放在 TextBlock 上，这样在子元素上绑定 DataContext 为 Menu
<Button DataContext="{Binding PlatformDemo}">
<Grid DataContext="{Binding Menu}" ContextMenu="{StaticResource zt}">
<TextBlock Text="Button 的子元素上来绑定菜单 " />
<Grid/>
</Button>
上面只能应对简单情况，如果子元素上又有元素绑定 PlatformDemo 中的对象呢，如下 TextBlock 需要绑定 PlatformDemo 中的 SomeName
<Button DataContext="{Binding PlatformDemo}">
<Grid DataContext="{Binding Menu}" ContextMenu="{StaticResource zt}">
<TextBlock Text="{Binding SomeName}" />
<Grid/>
</Button>
使用附加属性绑定菜单的上下文（推荐）
使用场景
- 菜单内容在资源文件中定义
- 菜单中的属性或者命令绑定了属性
- 整个菜单需要绑定一个属性
- 解决默认下不能同时引用资源又绑定菜单上下文的问题
附件属性脚本
using ESUI.Services.api;
using System;
using System.Windows;
using System.Windows.Controls;
using System.Reflection;
using System.Diagnostics;
using System.Windows.Data;
namespace ESUI.Utilities
{
/// <summary>
/// 上下文菜单帮助类
/// </summary>
public static class ContextMenuHelper
{
#region 附加属性
public static readonly DependencyProperty DataContextProperty =
DependencyProperty.RegisterAttached(
"DataContext",
typeof(object),
typeof(ContextMenuHelper),
new PropertyMetadata(null, OnDataContextChanged));
public static void SetDataContext(UIElement element, object value)
{
element.SetValue(DataContextProperty, value);
}
public static object GetDataContext(UIElement element)
{
return element.GetValue(DataContextProperty);
}
private static void OnDataContextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (d is UIElement element && element is FrameworkElement frameworkElement)
{
// 获取绑定的值
var contextMenu = frameworkElement.ContextMenu;
if (contextMenu != null)
{
contextMenu.SetBinding(ContextMenu.DataContextProperty,
new Binding { Source = e.NewValue });
}
}
}
#endregion
private static IESUIService _service;
/// <summary>
/// 提供此静态属性给 前端 xaml 进行绑定
/// 使用案例
/// 根节点引入命名空间： xmlns:esui_util="clr-namespace:ESUI.Utilities;assembly=ESUI"
/// 在需要上下文菜单的元素节点使用 ContextMenuOpening="{x:Static esui_util:ContextMenuHelper.ContextMenuOpeningHandler}"
/// </summary>
public static ContextMenuEventHandler ContextMenuOpening
{
get; internal set;
}
static ContextMenuHelper()
{
ContextMenuOpening = ContextMenuOpeningHandler;
}
internal static void Init(IESUIService service)
{
_service = service;
}
private static void ContextMenuOpeningHandler(object sender, ContextMenuEventArgs e)
{
e.Handled = !_service.IsMenuActive;
}
}
}
菜单资源定义
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ContextMenu x:Key="_menu">
<MenuItem Header="{Binding Menu.Name}" />
<Separator />
<MenuItem Header="{Binding Menu.ItemName}" />
</ContextMenu>
</ResourceDictionary>
前端引用资源
<Button DataContext="{Binding PlatformDemo}" Content="{Binding Describe}"
esui_util:ContextMenuHelper.DataContext="{Binding ContextMenu.PlacementTarget.DataContext.Menu2, RelativeSource={RelativeSource Self}}"
ContextMenu="{StaticResource _menu}"
ContextMenuOpening="{x:Static esui_util:ContextMenuHelper.ContextMenuOpening}" >
</Button>
- 指定对象的上下文
DataContext="{Binding PlatformDemo}"，PlatformDemo中包含Menu属性 - 附件属性的使用
esui_util:ContextMenuHelper.DataContext="{Binding ContextMenu.PlacementTarget.DataContext.Menu, RelativeSource={RelativeSource Self}}"，其中的Menu名称就可以自定义了 - 资源引用
ContextMenu="{StaticResource _menu}" - 控制菜单激活
ContextMenuOpening="{x:Static esui_util:ContextMenuHelper.ContextMenuOpening}"
动态查找资源（拓展，没必要）
/// <summary>
/// FindResource
/// </summary>
/// <param name="fileName"></param>
/// <param name="resKey"></param>
/// <exception cref="Exception"></exception>
private static T FindResource<T>(string fileName,string resKey)
{
// 获取资源文件的路径
string resourceFilePath = $"pack://application:,,,/ESUI;component/MenuViews/{fileName}.xaml";
// 创建一个ResourceDictionary并加载该资源文件
ResourceDictionary resourceDictionary = new ResourceDictionary();
resourceDictionary.Source = new Uri(resourceFilePath, UriKind.Absolute);
if (resourceDictionary.Count == 0)
{
throw new Exception($"“{resourceFilePath}” 中未定义资源");
}
if(resourceDictionary.Contains(resKey)) //注意 中包含了自身定义的资源也包含引入的
{
return (T)resourceDictionary[resKey];
}
else
{
throw new Exception($"“{resourceFilePath}” 中未找到 “{resKey}” 资源");
}
}
// 动态绑定菜单资源
private static void ContextMenuOpeningHandler(object sender, ContextMenuEventArgs e)
{
if(_service.IsMenuActive)
{
FrameworkElement el = sender as FrameworkElement;
// "fileName", "key" 两个值通过 tag 或者 uid 传进来
el.ContextMenu = FindResource<ContextMenu>("fileName", "key");
if (el.ContextMenu.DataContext == null)
{
string vmName = el.Tag == null ? "Menu" : el.Tag.ToString();
BindingFlags bindingFlags = BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance;
var d = el.DataContext.GetType().GetProperty(vmName, bindingFlags);
object vm = null;
vm = d.GetValue(el.DataContext);
el.ContextMenu.DataContext = vm;
}
}
e.Handled = !_service.IsMenuActive;
}