Devexress Mvvm CodeGenerator

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• Devexress Mvvm CodeGenerator에 대해서 정리합니다.

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CodeGenerator?

• 컴파일 시점에서 ViewModel에 대한 보일러플레이트 코드를 생성
• 이렇게 생성된 ViewModel은 INotifyPropertyChanged, INotifyPropertyChanging, IDataErrorInfo, ISupportServices 등의 구현을 포함
  • CodeGenerator 사이트 : https://github.com/DevExpress/DevExpress.Mvvm.CodeGenerators

사전 요건

• C# 9+ (VB는 지원되지 않음)
• .NET Framework v4.6.1+ 또는 .NET Core v3.0+
• Visual Studio v16.9.0+

Nuget 설치

• DevExpress.Mvvm.v21.1+에 대한 참조를 추가하거나 DevExpress.Mvvm NuGet 패키지를 설치합니다.
• 프로젝트에 DevExpress.Mvvm.CodeGenerators NuGet 패키지를 설치합니다.
  • CodeGenerator의 버전은 기존의 DevExpress 버전과 무관합니다.
    

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CodeGenerator 사용하기

using DevExpress.Mvvm.CodeGenerators;

[GenerateViewModel]
partial class ViewModel {
    [GenerateProperty]
    string username;

    [GenerateProperty]
    string status;

    [GenerateCommand]
    void Login() => Status = "User: " + Username;

    bool CanLogin() => !string.IsNullOrEmpty(Username);
}

• 대비되는 코드는 다음과 같습니다.

  partial class ViewModel : INotifyPropertyChanged {
  public event PropertyChangedEventHandler? PropertyChanged;
  
  protected void RaisePropertyChanged(PropertyChangedEventArgs e) => PropertyChanged?.Invoke(this, e);
  
  public string? Username {
      get => username;
      set {
          if(EqualityComparer<string?>.Default.Equals(username, value)) return;
          username = value;
          RaisePropertyChanged(UsernameChangedEventArgs);
      }
  }
  
  public string? Status {
      get => status;
      set {
          if(EqualityComparer<string?>.Default.Equals(status, value)) return;
          status = value;
          RaisePropertyChanged(StatusChangedEventArgs);
      }
  }
  
  DelegateCommand? loginCommand;
  
  public DelegateCommand LoginCommand {
      get => loginCommand ??= new DelegateCommand(Login, CanLogin, true);
  }
  
  static PropertyChangedEventArgs UsernameChangedEventArgs = new PropertyChangedEventArgs(nameof(Username));
  static PropertyChangedEventArgs StatusChangedEventArgs = new PropertyChangedEventArgs(nameof(Status));
  }

• 영상 제공 : https://github.com/DevExpress/DevExpress.Mvvm.CodeGenerators

• View Models Generated at Compile Time

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심화

• CodeGenerator 문서 : https://docs.devexpress.com/WPF/402989/mvvm-framework/viewmodels/compile-time-generated-viewmodels

String Length

• Usage

  [GenerateViewModel]
  partial class ViewModel {
  [GenerateProperty]
  [StringLength(100, MinimumLength = 5)] // this point
  string username;
  }

• Original

  partial class ViewModel : INotifyPropertyChanged {
  public event PropertyChangedEventHandler? PropertyChanged;
  
  protected void RaisePropertyChanged(PropertyChangedEventArgs e) => PropertyChanged?.Invoke(this, e);
  
  [System.ComponentModel.DataAnnotations.StringLengthAttribute(100, MinimumLength = 5)]  // this point
  public string? Username {
      get => username;
      set {
          if(EqualityComparer<string?>.Default.Equals(username, value)) return;
          username = value;
          RaisePropertyChanged(UsernameChangedEventArgs);
      }
  }
  
  static PropertyChangedEventArgs UsernameChangedEventArgs = new PropertyChangedEventArgs(nameof(Username));
  }

OnChangeMethod

• Usage

  [GenerateViewModel]
  public partial class ViewModel {
      [GenerateProperty(OnChangedMethod = nameof(CustomName))]  // this point
      string username;
  
      void CustomName() { }
  }

• Original

  partial class ViewModel : INotifyPropertyChanged {
  public event PropertyChangedEventHandler? PropertyChanged;
  
  protected void RaisePropertyChanged(PropertyChangedEventArgs e) => PropertyChanged?.Invoke(this, e);
  
  public string? Username {
      get => username;
      set {
          if(EqualityComparer<string?>.Default.Equals(username, value)) return;
          username = value;
          RaisePropertyChanged(UserNameChangedEventArgs);
          CustomName();  // this point
      }
  }
  
  static PropertyChangedEventArgs UsernameChangedEventArgs = new PropertyChangedEventArgs(nameof(Username));
  }

Async Command (1)

• Usage

  [GenerateViewModel]
  partial class ViewModel {
  [GenerateCommand (AllowMultipleExecution = true)]
  async Task CalculateAsync() {
      //...
  }
  }

• Original

  partial class ViewModel : INotifyPropertyChanged {
  public event PropertyChangedEventHandler? PropertyChanged;
  
  protected void RaisePropertyChanged(PropertyChangedEventArgs e) => PropertyChanged?.Invoke(this, e);
  
  AsyncCommand? calculateAsyncCommand;
  public AsyncCommand CalculateAsyncCommand {
      get => calculateAsyncCommand ??= new AsyncCommand(CalculateAsync, null, true, true);
  }
  }

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연동 가능

• 다음 내용과 연동 가능합니다.
  • 사이트 : https://docs.devexpress.com/WPF/402989/mvvm-framework/viewmodels/compile-time-generated-viewmodels#third-party-library-support
• https://prismlibrary.com/
• https://github.com/lbugnion/mvvmlight

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Example

• DevExpress MVVM CodeGenerator
  • DevExpressMVVMExample.zip
• https://github.com/SagiK-Repository/POC_.Net_DevExpress/tree/main/DevExpressMVVMExample