Question

我正在使用this blog post来实现动态网格。

但是，当我更改全局类变量的行数和列数时，似乎无法正常工作。

我正在通过上面的链接使用GridHelpers.cs类，而我的@ApplicationScoped int16_t getLastValueFromADC();看起来像这样

volatile uint16_t *ip;

我的CS代码如下：

UserControl

当我在文本框中键入行数和列数并按我的按钮时出现错误时，任何帮助将不胜感激，但是不会调用GridHelpers行数和列数已更改的事件。

我也将属性更改为此，但是在更改事件的xaml类中，<UserControl x:Class="WPFPurpleButtonTest.InstrumentUserControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:local="clr-namespace:WPFPurpleButtonTest" mc:Ignorable="d" d:DesignHeight="450" d:DesignWidth="800"> <Grid> <Label x:Name="colourName" Content="PURPLE" HorizontalAlignment="Left" Height="93" Margin="284,88,0,0" VerticalAlignment="Top" Width="243" FontWeight="Bold" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="50" Foreground="#FFDC00FF"/> <Button x:Name="testButton" Content="Button" HorizontalAlignment="Left" Margin="354,234,0,0" VerticalAlignment="Top" Width="75" Click="TestButton_Click"/> <Label x:Name="label" Content="Row Size" HorizontalAlignment="Left" Margin="222,296,0,0" VerticalAlignment="Top" Foreground="#FFDC00FF"/> <Label x:Name="label_Copy" Content="Column Size" HorizontalAlignment="Left" Margin="438,296,0,0" VerticalAlignment="Top" Foreground="#FFDC00FF"/> <Button x:Name="createGrid" Content="Create Grid" HorizontalAlignment="Left" Margin="357,348,0,0" VerticalAlignment="Top" Width="75" Click="CreateGrid_Click"/> <TextBox x:Name="rowSizeText" HorizontalAlignment="Left" Height="23" Margin="296,299,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="62"/> <TextBox x:Name="columnSizeText" HorizontalAlignment="Left" Height="23" Margin="528,300,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="62"/> <Grid local:GridHelpers.RowCount="{Binding RowCount}" local:GridHelpers.ColumnCount="{Binding ColumnCount}" ></Grid> </Grid> </UserControl>以using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; 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.Navigation; using System.Windows.Shapes; namespace WPFPurpleButtonTest { /// <summary> /// Interaction logic for InstrumentUserControl.xaml /// </summary> public partial class InstrumentUserControl : UserControl { // We should put this in a separate user control, but for now for testing // let's put the grid configuration in here public int RowCount { get; set; } public int ColumnCount { get; set; } public InstrumentUserControl() { InitializeComponent(); DataContext = this; } private void TestButton_Click(object sender, RoutedEventArgs e) { MessageBox.Show("HELLO!", "Greetings", MessageBoxButton.OK, MessageBoxImage.Information); } private void CreateGrid_Click(object sender, RoutedEventArgs e) { if (int.TryParse(rowSizeText.Text, out int rowResult)) { RowCount = rowResult; } if (int.TryParse(columnSizeText.Text, out int columnResult)) { ColumnCount = rowResult; } } } }而不是GridHelpers出现，因此它只是返回。

obj

Answer 1

您必须在ViewModel类上实现INotifyPropertyChanged。在您的情况下，您已设置“ DataContext = this”，因此必须在UserControl类上实现INotifyPropertyChanged。

我已经或多或少地定义了最小可能的实现方式...

using System.Windows;
using System.ComponentModel;

namespace GridHelperTest
{
  /// <summary>
  /// Interaction logic for MainWindow.xaml
  /// </summary>
  public partial class MainWindow : Window, INotifyPropertyChanged
  {
    public int RowCount { get; set; }
    public int ColumnCount { get; set; }

    public MainWindow ( )
    {
      InitializeComponent ();
      DataContext = this ;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void TestButton_Click (object sender, RoutedEventArgs e)
    {
      MessageBox.Show ( "HELLO!", "Greetings", MessageBoxButton.OK, MessageBoxImage.Information );
    }

    private void CreateGrid_Click (object sender, RoutedEventArgs e)
    {
      if (int.TryParse ( rowSizeText.Text, out int rowResult ))
      {
        RowCount = rowResult;
        OnPropertyChanged("RowCount");
      }

      if (int.TryParse ( columnSizeText.Text, out int columnResult ))
      {
        ColumnCount = rowResult;
        OnPropertyChanged("ColumnCount");
      }
    }
    protected virtual void OnPropertyChanged(string propertyName = null)
    {
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
  }
}

设置属性后，

调用OnPropertyChanged。通常，您可能希望使用属性设置器方法进行此操作。

为了测试它，我在网格中定义了一些彩色矩形。它们最初彼此重叠，但是在设置行数和列数之后，它们被放置在单独的单元格中。

<Window x:Class="GridHelperTest.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:GridHelperTest"
        mc:Ignorable="d"
        Title="MainWindow" Height="900" Width="800">

  <Grid>
    <Grid.RowDefinitions>
      <RowDefinition Height="*"/>
      <RowDefinition Height="*"/>
    </Grid.RowDefinitions>

    <Grid Grid.Row="0">
      <Label x:Name="colourName" Content="PURPLE" HorizontalAlignment="Left" Height="93" Margin="284,88,0,0" VerticalAlignment="Top" Width="243" FontWeight="Bold" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="50" Foreground="#FFDC00FF"/>
      <Button x:Name="testButton" Content="Button" HorizontalAlignment="Left" Margin="354,234,0,0" VerticalAlignment="Top" Width="75" Click="TestButton_Click"/>
      <Label x:Name="label" Content="Row Size" HorizontalAlignment="Left" Margin="222,296,0,0" VerticalAlignment="Top" Foreground="#FFDC00FF"/>
      <Label x:Name="label_Copy" Content="Column Size" HorizontalAlignment="Left" Margin="438,296,0,0" VerticalAlignment="Top" Foreground="#FFDC00FF"/>
      <Button x:Name="createGrid" Content="Create Grid" HorizontalAlignment="Left" Margin="357,348,0,0" VerticalAlignment="Top" Width="75" Click="CreateGrid_Click"/>
      <TextBox x:Name="rowSizeText" HorizontalAlignment="Left" Height="23" Margin="296,299,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="62"/>
      <TextBox x:Name="columnSizeText" HorizontalAlignment="Left" Height="23" Margin="528,300,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="62"/>

    </Grid>
    <Grid Grid.Row="1"
          local:GridHelpers.RowCount="{Binding RowCount}"
          local:GridHelpers.ColumnCount="{Binding ColumnCount}">
      <Rectangle Grid.Row="0" Grid.Column="0" Fill="Red" Width="100" Height="100"/>
      <Rectangle Grid.Row="0" Grid.Column="1" Fill="Green" Width="100" Height="100"/>
      <Rectangle Grid.Row="1" Grid.Column="0" Fill="Blue" Width="100" Height="100"/>
      <Rectangle Grid.Row="1" Grid.Column="1" Fill="Yellow" Width="100" Height="100"/>

    </Grid>
  </Grid>
</Window>

那与您的XAML并不完全相同，因为我是在Window而不是UserControl中定义的。

使用XAML的动态网格行数和列数

1 个答案: