C# CanExecute抛出异常
在我的XAML代码中,我发出了一些命令:C# CanExecute抛出异常,c#,.net,wpf,C#,.net,Wpf,在我的XAML代码中,我发出了一些命令: <Window.CommandBindings> <CommandBinding Command="ApplicationCommands.Open" Executed="OpenCommandHandler" /> <CommandBinding Command="ApplicationCommands.Save" Executed="SaveCommandHandler" CanExecuted="Ca
<Window.CommandBindings>
<CommandBinding Command="ApplicationCommands.Open" Executed="OpenCommandHandler" />
<CommandBinding Command="ApplicationCommands.Save" Executed="SaveCommandHandler" CanExecuted="CanSaveCommandHandler" />
<CommandBinding Command="ApplicationCommands.Delete" Executed="DeleteCommandHandler" CanExecuted="CanDeleteCommandHandler" />
<CommandBinding Command="{x:Static local:MainWindow.AddCommand}" Executed="AddCommandHandler" CanExecuted="CanAddCommandHandler" />
我的CanExecute方法是什么样子的:
private ResearcherObservableCollection list;
public Researcher res;
public static RoutedCommand AddCommand = new RoutedCommand("Add", typeof(WpfApplication3.MainWindow));
private int _errors = 0;
public MainWindow()
{
InitializeComponent();
list = new ResearcherObservableCollection();
res = new Researcher();
this.DataContext = list;
}
private void CanSaveCommandHandler(object sender, CanExecuteRoutedEventArgs e)
{
if (list.Changes == true)
e.CanExecute = true;
else e.CanExecute = false;
}
private void CanAddCommandHandler(object sender, CanExecuteRoutedEventArgs e)
{
{
e.CanExecute = true;
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(Adding); i++)
{
var child = VisualTreeHelper.GetChild(Adding, i);
if (Validation.GetHasError(child)) { e.CanExecute = false; }
}
}
}
private void CanDeleteCommandHandler(object sender, CanExecuteRoutedEventArgs e)
{
if (((Project)this.projlst.SelectedItem) != null) e.CanExecute = true;
else e.CanExecute = false;
}
private researcherobservable收藏列表;
公共研究人员资源;
publicstaticroutedcommand AddCommand=newroutedcommand(“Add”,typeof(WpfApplication3.MainWindow));
私有int_错误=0;
公共主窗口()
{
初始化组件();
列表=新的ResearchRobservableCollection();
res=新研究人员();
this.DataContext=list;
}
私有void CanSaveCommandHandler(对象发送方,CanExecuteRouteEventArgs e)
{
if(list.Changes==true)
e、 CanExecute=true;
否则e.CanExecute=false;
}
私有void CanAddCommandHandler(对象发送方,CanExecuteRoutedEventArgs e)
{
{
e、 CanExecute=true;
for(int i=0;i
当我不使用CanExecute方法而只使用Executed时,一切都正常。但问题是,我必须在执行之前检查一些参数。我有一个例外。也许你也有类似的问题?如何更正代码?我处理了我的问题。我想CanExecute方法在我创建列表之前就被调用了。因此,我们必须检查它们是否为空:
private void CanAddCommandHandler(object sender, CanExecuteRoutedEventArgs e)
{
//if (VisualTreeHelper.GetChild(Adding))
{
e.CanExecute = true;
//for (int i = 0; i < VisualTreeHelper.GetChildrenCount(Adding); i++)
//{
// var child = VisualTreeHelper.GetChild(Adding, i);
// if (Validation.GetHasError(child)) { e.CanExecute = false; }
//}
if (Adding != null)
{
for (int i = 0; i < Adding.Children.Count; i++)
{
var child = Adding.Children[i];
if (Validation.GetHasError(child)) { e.CanExecute = false; break; }
}
}
else e.CanExecute = false;
}
}
private void CanSaveCommandHandler(object sender, CanExecuteRoutedEventArgs e)
{
if (lst != null)
{
if (list.Changes == true)
e.CanExecute = true;
else e.CanExecute = false;
}
else e.CanExecute = false;
}
private void CanDeleteCommandHandler(object sender, CanExecuteRoutedEventArgs e)
{
if (lst != null)
{
if (((Researcher)this.lst.SelectedItem) != null) e.CanExecute = true;
}
else e.CanExecute = false;
}
private void CanadCommandHandler(对象发送方,CanExecuteRouteEventArgs e)
{
//if(VisualTreeHelper.GetChild(添加))
{
e、 CanExecute=true;
//for(int i=0;i
XAML代码中的一些更改:
<Window.CommandBindings>
<CommandBinding Command="ApplicationCommands.Open" Executed="OpenCommandHandler" />
<CommandBinding Command="ApplicationCommands.Save" Executed="SaveCommandHandler" CanExecute="CanSaveCommandHandler" />
<CommandBinding
Command="ApplicationCommands.Delete"
CanExecute="CanDeleteCommandHandler"
Executed="DeleteCommandHandler" />
<CommandBinding Command="{x:Static local:MainWindow.AddCommand}" Executed="AddCommandHandler" CanExecute="CanAddCommandHandler"/>
</Window.CommandBindings>
您能查一下TargetInvocationException的innerexception是什么吗?是否执行了输入错误?当我编译它时,它应该是CanExecute
,Window没有;我没有加载,所以我决定调试,它说TargetInvocationException没有得到处理是的,CanExecute,但它仍然不起作用这是什么?是实例化的吗?请原谅我的英语(