向 ICommand 添加新方法 (C# WPF)

Question

这是我的助手 class，可用于我项目中的不同 ViewModelClass；

public class MOpenFileDialog : ViewModelBase
    {
        #region Properties

        private OpenFileDialog _openDialog;
        public OpenFileDialog Dialog
        {
            get { return _openDialog; }
            set 
            { 
                _openDialog = value;
                RaisePropertyChanged(nameof(Dialog));
            }
        }

        // some other properties

        #endregion

        #region Constructors

        public MOpenFileDialog()
        {            
            OpenFileCommand = new RelayCommand<object>(OpenFile);

            Dialog = new OpenFileDialog()
            {
                FileName = "Documen",
                Filter = "All Files|*.*",
            };
        }


        #endregion

        #region Methods

        public void OpenFile(object param)
        {
           // somecode
        }

        // some other methods

        #endregion

        #region Commands
        public ICommand OpenFileCommand { get; set; }

        #endregion


    }

在 myClassVM 中，我有一个 MOpenFileDialog 的瞬间，我正在尝试添加 OpenFileCommand 的新方法；

public class myClassVM : ViewModelBase
    {
        #region Properties

        public MOpenFileDialog Opendial { get; set; }

        #endregion

        #region Constructor

        public CollectNamesVM()
        {
            Opendial = new MOpenFileDialog() { };
            Opendial.Dialog.Multiselect = true;
            //Opendial.OpenFileCommand += CollectFilesFolder; // Wrong Way

        }

        #endregion

        #region Methods

        public void CollectFilesFolder()
        {
            // toDo
        }

       }

我想添加另一个在 openFileCommand 触发时执行的方法，我试错了，只是为了解释我想做什么。

任何帮助将不胜感激。

Answer 1

在下面的5步中使用delegate：

步骤 1。创建一个delegate。您想要使用代码传递 string[] (string 数组，data type of FileNames 的示例：Opendial.Dialog.Multiselect = true)

步骤 2。使用步骤 1

中的 delegate 创建一个 event

步骤 3。随时在 MOpenFileDialog

中提高在步骤 2 中创建的 event

步骤 4。我不知道你想要什么，但它和这个一样

步骤 5。 CollectFilesFolder 方法的参数与委托的参数相同

    // 1. Create a delegate. Example you want to pass an string array
    public delegate void OpenFileCommand(string[] fileNames);
    public class MOpenFileDialog : ViewModelBase
    {
        // 2. Create a event using the delegate in step 1
        public event OpenFileCommand OnOpenFileCommand;

        // 3. Raise the event created in step 2 everywhen you want
        public void SomeMethod(string[] fileNames)
        {
            this.OnOpenFileCommand.Invoke(fileNames);
        }

        #region Properties

        private OpenFileDialog _openDialog;
        public OpenFileDialog Dialog
        {
            get { return _openDialog; }
            set 
            { 
                _openDialog = value;
                RaisePropertyChanged(nameof(Dialog));
            }
        }

        // some other properties

        #endregion

        #region Constructors

        public MOpenFileDialog()
        {            
            OpenFileCommand = new RelayCommand<object>(OpenFile);

            Dialog = new OpenFileDialog()
            {
                FileName = "Documen",
                Filter = "All Files|*.*",
            };
        }


        #endregion

        #region Methods

        public void OpenFile(object param)
        {
           // somecode
        }

        // some other methods

        #endregion

        #region Commands
        public ICommand OpenFileCommand { get; set; }

        #endregion
    }

    public class myClassVM : ViewModelBase
    {
        #region Properties

        public MOpenFileDialog Opendial { get; set; }

        #endregion

        #region Constructor

        public CollectNamesVM()
        {
            Opendial = new MOpenFileDialog() { };
            Opendial.Dialog.Multiselect = true;
            // 4. I cant know what do you want here, but Its same as this
            Opendial.OnOpenFileCommand += CollectFilesFolder(Opendial.Dialog.FileNames); // Wrong Way

        }

        #endregion

        #region Methods
        // 5. CollectFilesFolder has params same as the delegate
        public void CollectFilesFolder(string[] fileNames)
        {
            // toDo
        }
    }

向 ICommand 添加新方法 (C# WPF)

adding a new method to ICommand (C# WPF)

c#

wpf

mvvm

relaycommand