MvvmCross 自定义事件绑定事件参数

Question

我使用 MvvmCross 在 EditText 上为 FocusChange 事件创建了自定义绑定。我可以绑定并触发事件，但我不知道如何传递事件参数。我的自定义绑定是这个

using Android.Views;
using Android.Widget;
using Cirrious.MvvmCross.Binding;
using Cirrious.MvvmCross.Binding.Droid.Target;
using Cirrious.MvvmCross.Binding.Droid.Views;
using Cirrious.MvvmCross.ViewModels;
using System;

namespace MPS_Mobile_Driver.Droid.Bindings
{
    public class MvxEditTextFocusChangeBinding
        : MvxAndroidTargetBinding
    {
        private readonly EditText _editText;
        private IMvxCommand _command;

        public MvxEditTextFocusChangeBinding(EditText editText) : base(editText)
        {
            _editText = editText;
            _editText.FocusChange  += editTextOnFocusChange;
        }

        private void editTextOnFocusChange(object sender, EditText.FocusChangeEventArgs eventArgs)
        {
            if (_command != null)
            {
                _command.Execute( eventArgs );
            }
        }

        public override void SetValue(object value)
        {
            _command = (IMvxCommand)value;
        }

        protected override void Dispose(bool isDisposing)
        {
            if (isDisposing)
            {
                _editText.FocusChange -= editTextOnFocusChange;
            }
            base.Dispose(isDisposing);
        }

        public override Type TargetType
        {
            get { return typeof(IMvxCommand); }
        }

        protected override void SetValueImpl(object target, object value)
        {
        }

        public override MvxBindingMode DefaultMode
        {
            get { return MvxBindingMode.OneWay; }
        }
    }
}

我将它连接到我的 ViewModel 中，如下所示：

public IMvxCommand FocusChange
{
    get
    {
        return new MvxCommand(() =>
            OnFocusChange()
            );
    }
}

private void OnFocusChange()
{
    //Do Something
}

有没有办法做类似

的事情

public IMvxCommand FocusChange
{
    get
    {
        return new MvxCommand((e) =>
            OnFocusChange(e)
            );
    }
}

private void OnFocusChange(EditText.FocusChangeEventArgs e)
{
    //Do Something
}

我在那里尝试做的事情没有用，但我希望有类似的东西可能有用。当命令在使用此行的自定义绑定中触发时，我能够传递 eventargs

            _command.Execute( eventArgs );

我只是想不出在 ViewModel 中捕捉它们的方法。谁能帮我解决这个问题？

吉姆

Answer 1

在尝试了许多不同的安排后，我发现连接 MvxCommand 的正确语法是

public IMvxCommand FocusChange
{
    get
    {
        return new MvxCommand<EditText.FocusChangeEventArgs>(e => OnFocusChange(e));
    }
}

private void OnFocusChange(EditText.FocusChangeEventArgs e)
{
    if (!e.HasFocus)
    {
         //Do Something
    }
}

希望对您有所帮助！

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