0.Description

CommunityToolkit.Mvvm8.1 has a major update function: the source generator function, which greatly simplifies our mvvm code

But this article summarizes the original writing method first, and then summarizes the source generator function in the next article

1. Model definition

Must inherit: ObservableObject

2. viewmodel code implementation

A few key points:

SetProperty is to assign values to properties and notify change notifications
ButtonClickCommand.NotifyCanExecuteChanged(); //Notification command has changed
RelayCommand ButtonClickCommand //Definition command

namespace WpfDemoNet6.Demo
 {
     public class DataViewModel1 : ObservableObject
     {
         private string title = "hello";

         public string Title
         {
             get
             {
                 return title;
             }
             set
             {
                 //title = value;
                 //PropertyChanged?.Invoke( this , new PropertyChangedEventArgs( "Name" ) );

                 //SetProperty is equivalent to setting the value, and the PropertyChanged notification call
                 SetProperty( ref title , value );
             }
         }

         private bool isEnabled = false;

         /// 
         /// Is it possible to use
         /// 
         public bool IsEnabled
         {
             get => isEnabled;
             set
             {
                 SetProperty( ref isEnabled , value );

                 // Notify that the command has changed
                 ButtonClickCommand. NotifyCanExecuteChanged();
             }
         }

         /// 
         /// Order
         /// 
         public RelayCommand ButtonClickCommand
         {
             get;
         }

         public DataViewModel1 ()
         {
             //The first parameter of RelayCommand is the command call statement
             // Whether the second parameter (optional) is allowed to be used
             ButtonClickCommand = new RelayCommand( () =>
             {
                 //Click the button to modify the title
                 Title = "hello(change)";
             } , () =>
             {
                 return IsEnabled;
             } );

             ButtonClickCommandPar = new RelayCommand( ( double val ) =>
             {
                 Title = $"hello(change):{val}";
             } );
         }


         public RelayCommand ButtonClickCommandPar
         {
             get;
         }
     }
 }

3. Asynchronous command

The asynchronous command will automatically control the visibility of the control, and provide an IsRunning property to determine whether the asynchronous is complete

public DataViewModel1 ()
 {
     AsyncButtonClickCommand = new AsyncRelayCommand( RunTxtAsync );
     AsyncButtonParClickCommand = new AsyncRelayCommand( RunTxtParAsync );
 }

 /*
 Special Note: The asynchronous command will automatically control the visibility of the control, and provide an IsRunning property to determine whether the asynchronous command is complete
 */

 /// 
 /// Order
 /// 
 public IAsyncRelayCommand AsyncButtonClickCommand
 {
     get;
 }

 private async Task RunTxtAsync()
 {
     await Task. Delay( 4800 );
     Title = "hello(Task changed)";
 }


 /// 
 /// command (with parameters)
 /// 
 public IAsyncRelayCommand AsyncButtonParClickCommand
 {
     get;
 }

 private async Task RunTxtParAsync ( double val )
 {
     await Task. Delay( 4800 );
     Title = $"hello(Task change):{val}";
 }

My Series
A.Sql Server2005 Transact-SQL new weapon learning
B.MCAD learning
C.Code Reading Summary
D.ASP.NET State Management
E.DB (database)
F.WAP
G.WinForm STRONG>

H.Flex

I hope the knowledge mentioned above can give you some hints, and welcome to exchange and correct.
Author: aierong
Source: http://www.cnblogs.com/aierong
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