[英]Overloaded method for DelegateCommand
I have a DelegateCommand class and within it 2 constructors. 我有一个DelegateCommand类,其中有2个构造函数。 When I pass my property to the constructor of that class I get an error message that says:
当我将属性传递给该类的构造函数时,我收到一条错误消息,内容为:
Error 1 The best overloaded method match for 'QMAC.ViewModels.DelegateCommand.DelegateCommand(System.Action<object>)' has some invalid arguments
Error 2 Argument 1: cannot convert from 'System.Windows.Input.ICommand' to 'System.Action<object>'
For my DelegateCommand, here is what I have (without comments to keep it short): 对于我的DelegateCommand,这是我所拥有的(不加任何评论以使其简短):
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Input;
namespace QMAC.ViewModels
{
class DelegateCommand : ICommand
{
private Action<object> _execute;
private Predicate<object> _canExecute;
public DelegateCommand(Action<object> execute) : this(execute, null)
{
}
public DelegateCommand(Action<object> execute, Predicate<object> canExecute)
{
_execute = execute;
_canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
if (_canExecute.Equals(null))
{
return true;
}
return _canExecute(parameter);
}
public void Execute(object parameter)
{
_execute(parameter);
}
public void RaiseCanExecuteChanged()
{
if (CanExecuteChanged != null)
{
CanExecuteChanged(this, EventArgs.Empty);
}
}
}
}
Here is the property and the function that I am trying to pass: 这是我要传递的属性和功能:
using QMAC.Models;
using System;
using System.Collections.Generic;
using System.Net.NetworkInformation;
using System.Text;
using System.Windows.Input;
using System.Windows.Threading;
namespace QMAC.ViewModels
{
class MainViewModel: ViewModelBase
{
Address address;
Location location;
private string _locationPicked;
private string _ipAddress;
private DelegateCommand _exportCommand;
public MainViewModel()
{
address = new Address();
location = new Location();
_ipAddress = address.IPAddress;
_exportCommand = new DelegateCommand(ExportCommand);
}
public ICommand ExportCommand
{
get { return _exportCommand; }
}
public void ExportList()
{
}
}
}
Because the 1st error has to deal with an overloaded method I know I'm just overlooking something really simple. 因为第一个错误必须处理重载方法,所以我知道我只是忽略了一些非常简单的东西。 As for the second error, what would be a better way to handle that since I can't pass that Property.
至于第二个错误,由于我无法传递该Property,因此是一种更好的处理方法。
Your constructor for the DelegateCommand
is configured to take and Action<object>
not you are instead passing an ICommand
instance. 您的
DelegateCommand
构造函数已配置为采用Action<object>
而不是传递ICommand
实例。
You should be constructing with the action that should be taking place. 您应该使用应该采取的措施进行构建。 For example, I think you mean to call "ExportList" instead:
例如,我认为您的意思是调用“ ExportList”:
_exportCommand = new DelegateCommand((o) => this.ExportList());
Note: because ExportList doesn't actually have an object parameter you need to use an anonymous method to make the call. 注意:由于ExportList实际上没有对象参数,因此您需要使用匿名方法进行调用。
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