C# 如何在代码中为DataTemplate分配事件处理程序?
我尝试通过代码动态创建C# 如何在代码中为DataTemplate分配事件处理程序?,c#,wpf,mvvm,datagrid,C#,Wpf,Mvvm,Datagrid,我尝试通过代码动态创建DataGrid的HeaderTemplate,并将其分配给DataGrid。为此,我有一个方法GetDatatemplate(string fromstring),它定义了一个XML文本,然后使用它创建一个DataTemplate。只要在DataTemplate中不包含MouseLeftButtonDown事件处理程序,这就可以正常工作 MyDataTemplate保存在string变量中,该变量名为StringHeaderTemplate,位于MainWindow.xa
DataGrid
的HeaderTemplate
,并将其分配给DataGrid
。为此,我有一个方法GetDatatemplate(string fromstring)
,它定义了一个XML文本,然后使用它创建一个DataTemplate
。只要在DataTemplate
中不包含MouseLeftButtonDown
事件处理程序,这就可以正常工作
MyDataTemplate
保存在string
变量中,该变量名为StringHeaderTemplate
,位于MainWindow.xaml.cs的代码隐藏中:
private string StringHeaderTemplate =@"<DataTemplate>
<DataTemplate.Resources>
<ControlTemplate x:Key=""imgNo"" TargetType=""{x:Type Control}"">
<Image Source = ""pack://application:,,,/Images/upArrow.png"" />
</ControlTemplate >
<ControlTemplate x:Key=""imgUp"" TargetType=""{x:Type Control}"">
<Image Source = ""pack://application:,,,/Images/upArrow.png"" />
</ControlTemplate >
<ControlTemplate x:Key=""imgDown"" TargetType=""{x:Type Control}"" >
<Image Source = ""pack://application:,,,/Images/downArrow.png"" />
</ControlTemplate >
</DataTemplate.Resources>
<Grid Background=""Transparent"" MouseLeftButtonDown=""Grid_MouseLeftButtonDown"">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Content=""Hello""/>
<TextBlock Grid.Row=""1"" HorizontalAlignment= ""Center"" Text = ""TextBlock"" />
<CheckBox Grid.Row= ""2"" HorizontalAlignment= ""Center"" IsChecked= ""True"" />
</Grid >
</DataTemplate>";
然后我将这个DataTemplate
应用到DataGrid
的HeaderTemplate
:
private void dg_AutoGeneratingColumn_1(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
DataTemplate dtCell = null;
DataTemplate dtHeader = null;
string dtString = string.Empty;
string dtHeaderString = string.Empty;
switch(Type.GetTypeCode(e.PropertyType))
{
case TypeCode.String:
dtString = StringTemplate.Replace("xxColumnxx", e.PropertyName);
dtHeaderString=StringHeaderTemplate;
break;
}
if(!string.IsNullOrEmpty(dtString))
{
dtCell = GetDataTemplateForDataGrid(dtCellString);
dtHeader = GetDataTemplateForDataGrid(dtHeaderString);
DataGridTemplateColumn c = new DataGridTemplateColumn()
{
CellTemplate = dtCell,
HeaderTemplate = dtHeader,
};
e.Column = c;
}
}
事件处理程序非常简单:
private void Grid_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
MessageBox.Show(DateTime.Now.ToString());
}
我得到的异常是一个XamlParseException,它的InnerException类型为ArgumentException,表示:
“无法绑定到目标方法,因为其签名或安全性
透明度与委托类型的透明度不兼容。“
你知道怎么做吗
更新:
我试图通过命令
进行绑定,但是没有调用调用排序命令
。也许你知道我做错了什么
<Grid Background=""Transparent"">
<i:Interaction.Triggers>
<i:EventTrigger EventName=""MouseLeftButtonDown"">
<prism:InvokeCommandAction Command = ""{Binding
RelativeSource={RelativeSource AncestorType=Window,
Mode=FindAncestor}, Path=DataContext.CallSortingCommand}"" />
</i:EventTrigger>
</i:Interaction.Triggers>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Content=""Hello""/>
<TextBlock Grid.Row=""1"" HorizontalAlignment= ""Center"" Text = ""TextBlock"" />
CheckBox Grid.Row= ""2"" HorizontalAlignment= ""Center"" IsChecked= ""True"" />
</Grid >
复选框Grid.Row=”“2”“HorizontalAlignment=”“Center”“IsChecked=”“True”“/>
这是一个有趣的问题,因为可能的解决方案是在应用数据模板后,在可视化树中查找要订阅的对象。但它是一个列,在这种情况下很难访问可视化树
我建议使用交互,它允许在XAML中定义事件触发器。请查看以下代码:
private string StringHeaderTemplate = @"<DataTemplate>
<Grid Background=""Transparent"">
<i:Interaction.Triggers>
<i:EventTrigger EventName=""MouseLeftButtonDown"">
<si:CallMethodAction MethodName = ""Grid_MouseLeftButtonDown"" TargetObject=""{Binding RelativeSource={RelativeSource AncestorType=Window}}""/>
</i:EventTrigger>
</i:Interaction.Triggers>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Content=""Hello""/>
<TextBlock Grid.Row=""1"" HorizontalAlignment= ""Center"" Text = ""TextBlock"" />
<CheckBox Grid.Row= ""2"" HorizontalAlignment= ""Center"" IsChecked= ""True"" />
</Grid >
</DataTemplate>";
public void Grid_MouseLeftButtonDown(object sender, RoutedEventArgs e)
{
MessageBox.Show(DateTime.Now.ToString());
}
private DataTemplate GetDatatemplate(string fromstring)
{
ParserContext context = new ParserContext();
context.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
context.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");
context.XmlnsDictionary.Add("i", "clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity");
context.XmlnsDictionary.Add("si", "clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions");
return (DataTemplate)XamlReader.Parse(fromstring, context);
}
私有字符串StringHeaderTemplate=@”
";
公共无效网格\u MouseLeftButtonDown(对象发送器,RoutedEventArgs e)
{
Show(DateTime.Now.ToString());
}
私有数据模板GetDatatemplate(string fromstring)
{
ParserContext上下文=新的ParserContext();
context.xmlnsdirectionary.Add(“,”http://schemas.microsoft.com/winfx/2006/xaml/presentation");
context.xmlnsdirectionary.Add(“x”http://schemas.microsoft.com/winfx/2006/xaml");
Add(“i”,“clr命名空间:System.Windows.Interactivity;assembly=System.Windows.Interactivity”);
添加(“si”,“clr命名空间:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions”);
return(DataTemplate)XamlReader.Parse(fromstring,context);
}
另外,请注意Grid_MouseLeftButtonDown事件处理程序的公共访问修饰符,使用private将无法工作
更新
完整源代码:
XAML
C#
公共部分类主窗口:窗口
{
公共主窗口()
{
初始化组件();
DataContext=新的MainWindowViewModel();
}
私有字符串StringHeaderTemplate=@”
";
私有字符串DateTimeWithCommandHeaderTemplate=@”
";
专用字符串TimeCellTemplate=@”
";
私有字符串DescCellTemplate=@”
";
公共无效网格\u MouseLeftButtonDown(对象发送器,RoutedEventArgs e)
{
//Show(DateTime.Now.ToString());
var vm=作为MainWindowViewModel的DataContext;
vm.Items[0].Desc+=“+”;
}
私有数据模板GetDatatemplate(string fromstring)
{
ParserContext上下文=新的ParserContext();
context.xmlnsdirectionary.Add(“,”http://schemas.microsoft.com/winfx/2006/xaml/presentation");
context.xmlnsdirectionary.Add(“x”http://schemas.microsoft.com/winfx/2006/xaml");
Add(“i”,“clr命名空间:System.Windows.Interactivity;assembly=System.Windows.Interactivity”);
添加(“si”,“clr命名空间:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions”);
return(DataTemplate)XamlReader.Parse(fromstring,context);
}
私有void dg_AutoGeneratingColumn(对象发送方,DataGridAutoGeneratingColumnEventArgs e)
{
DataTemplate dtHeader=null;
string dtString=string.Empty;
字符串dtHeaderString=string.Empty;
DataGridTemplateColumn=null;
开关(Type.GetTypeCode(e.PropertyType))
{
大小写类型代码。字符串:
{
column=新的DataGridTemplateColumn()
{
CellTemplate=GetDatatemplate(DescCellTemplate),
HeaderTemplate=GetDatatemplate(StringHeaderTemplate),
};
}
打破
案例类型代码.DateTime:
{
column=新的DataGridTemplateColumn()
{
CellTemplate=GetDatatemplate(TimeCellTemplate),
HeaderTemplate=GetDatatemplate(DateTimeWithCommandHeaderTemplate),
};
}
打破
}
if(列!=null)
{
e、 列=列;
}
}
}
公共类MainWindowViewModel:INotifyPropertyChanged
{
公共事件属性更改事件处理程序属性更改;
公共主窗口视图模型()
{
private string StringHeaderTemplate = @"<DataTemplate>
<Grid Background=""Transparent"">
<i:Interaction.Triggers>
<i:EventTrigger EventName=""MouseLeftButtonDown"">
<si:CallMethodAction MethodName = ""Grid_MouseLeftButtonDown"" TargetObject=""{Binding RelativeSource={RelativeSource AncestorType=Window}}""/>
</i:EventTrigger>
</i:Interaction.Triggers>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Content=""Hello""/>
<TextBlock Grid.Row=""1"" HorizontalAlignment= ""Center"" Text = ""TextBlock"" />
<CheckBox Grid.Row= ""2"" HorizontalAlignment= ""Center"" IsChecked= ""True"" />
</Grid >
</DataTemplate>";
public void Grid_MouseLeftButtonDown(object sender, RoutedEventArgs e)
{
MessageBox.Show(DateTime.Now.ToString());
}
private DataTemplate GetDatatemplate(string fromstring)
{
ParserContext context = new ParserContext();
context.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
context.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");
context.XmlnsDictionary.Add("i", "clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity");
context.XmlnsDictionary.Add("si", "clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions");
return (DataTemplate)XamlReader.Parse(fromstring, context);
}
<Window x:Class="DataGridDataTemplateInCode.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:DataGridDataTemplateInCode"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Grid>
<DataGrid Name="dg" ItemsSource="{Binding Items}" AutoGeneratingColumn="dg_AutoGeneratingColumn" />
</Grid>
</Window>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainWindowViewModel();
}
private string StringHeaderTemplate = @"<DataTemplate>
<Grid Background=""Transparent"">
<i:Interaction.Triggers>
<i:EventTrigger EventName=""PreviewMouseLeftButtonDown"">
<si:CallMethodAction MethodName = ""Grid_MouseLeftButtonDown"" TargetObject=""{Binding RelativeSource={RelativeSource AncestorType=Window}}""/>
</i:EventTrigger>
</i:Interaction.Triggers>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Content=""Hello""/>
<TextBlock Grid.Row=""1"" HorizontalAlignment= ""Center"" Text = ""Grid_MouseLeftButtonDown"" />
<CheckBox Grid.Row= ""2"" HorizontalAlignment= ""Center"" IsChecked= ""True"" />
</Grid >
</DataTemplate>";
private string DateTimeWithCommandHeaderTemplate = @"<DataTemplate>
<Grid Background=""Transparent"">
<i:Interaction.Triggers>
<i:EventTrigger EventName=""MouseLeftButtonDown"">
<i:InvokeCommandAction Command = ""{Binding DataContext.CallSortingCommand, RelativeSource={RelativeSource AncestorType=Window}}""/>
</i:EventTrigger>
</i:Interaction.Triggers>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Content=""Hello""/>
<TextBlock Grid.Row=""1"" HorizontalAlignment= ""Center"" Text = ""CallSortingCommand"" />
<CheckBox Grid.Row= ""2"" HorizontalAlignment= ""Center"" IsChecked= ""True"" />
</Grid >
</DataTemplate>";
private string TimeCellTemplate = @"<DataTemplate>
<TextBlock HorizontalAlignment= ""Center"" Text = ""{Binding Time}"" />
</DataTemplate>";
private string DescCellTemplate = @"<DataTemplate>
<TextBlock HorizontalAlignment= ""Center"" Text = ""{Binding Desc}"" />
</DataTemplate>";
public void Grid_MouseLeftButtonDown(object sender, RoutedEventArgs e)
{
//MessageBox.Show(DateTime.Now.ToString());
var vm = DataContext as MainWindowViewModel;
vm.Items[0].Desc += "+";
}
private DataTemplate GetDatatemplate(string fromstring)
{
ParserContext context = new ParserContext();
context.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
context.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");
context.XmlnsDictionary.Add("i", "clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity");
context.XmlnsDictionary.Add("si", "clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions");
return (DataTemplate)XamlReader.Parse(fromstring, context);
}
private void dg_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
DataTemplate dtHeader = null;
string dtString = string.Empty;
string dtHeaderString = string.Empty;
DataGridTemplateColumn column = null;
switch (Type.GetTypeCode(e.PropertyType))
{
case TypeCode.String:
{
column = new DataGridTemplateColumn()
{
CellTemplate = GetDatatemplate(DescCellTemplate),
HeaderTemplate = GetDatatemplate(StringHeaderTemplate),
};
}
break;
case TypeCode.DateTime:
{
column = new DataGridTemplateColumn()
{
CellTemplate = GetDatatemplate(TimeCellTemplate),
HeaderTemplate = GetDatatemplate(DateTimeWithCommandHeaderTemplate),
};
}
break;
}
if (column != null)
{
e.Column = column;
}
}
}
public class MainWindowViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public MainWindowViewModel()
{
for (int i = 0; i < 10; i++)
{
_collection.Add(new MyObject() { Time = DateTime.Now.AddSeconds(i), Desc = i.ToString() });
}
CallSortingCommand = new DelegateCommand(OnCallSortingCommand, (o) => true);
}
private void OnCallSortingCommand(object obj)
{
MessageBox.Show("From OnCallSortingCommand");
}
public ICommand CallSortingCommand { get; set; }
private ObservableCollection<MyObject> _collection = new ObservableCollection<MyObject>();
public ObservableCollection<MyObject> Items
{
get
{
return _collection;
}
}
protected void OnPropertyChanged([CallerMemberName] string property = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
}
}
public class MyObject : INotifyPropertyChanged
{
public DateTime Time { get; set; }
private string _desc;
public string Desc
{
get { return _desc; }
set { _desc = value; PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Desc))); }
}
public event PropertyChangedEventHandler PropertyChanged;
}
public class DelegateCommand : ICommand
{
private readonly Action<object> _execute;
private readonly Func<object, bool> _canExecute;
public event EventHandler CanExecuteChanged;
public DelegateCommand(Action<object> execute, Func<object, bool> canExecute)
{
_execute = execute;
_canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
return _canExecute(parameter);
}
public void Execute(object parameter)
{
_execute(parameter);
}
}