IEditableObject Gränssnitt

Definition

Namnområde:

System.ComponentModel

Sammansättning:

System.dll

Tillhandahåller funktioner för att checka in eller återställa ändringar i ett objekt som används som datakälla.

public interface class IEditableObject

public interface IEditableObject

type IEditableObject = interface

Public Interface IEditableObject

Härledda

System.Data.DataRowView

Exempel

Följande exempel innehåller en enkel implementering av IEditableObject gränssnittet. Klassen Customer lagrar kundinformation och kan användas som en samling för en kunddatabas. Det här exemplet förutsätter att du har använt klassen CustomerList som finns i exemplet i IBindingList klassen.

public ref class Customer: public IEditableObject
{
private:
   ref struct CustomerData
   {
   internal:
      String^ id;
      String^ firstName;
      String^ lastName;
   };

internal:
   CustomersList^ parent;
   CustomerData^ custData;
   CustomerData^ backupData;
   bool inTxn;

   // Implements IEditableObject
public:
   virtual void BeginEdit()
   {
      Console::WriteLine( "Start BeginEdit" );
      if (  !inTxn )
      {
         this->backupData = custData;
         inTxn = true;
         Console::WriteLine( "BeginEdit - {0}", this->backupData->lastName );
      }

      Console::WriteLine( "End BeginEdit" );
   }

   virtual void CancelEdit()
   {
      Console::WriteLine( "Start CancelEdit" );
      if ( inTxn )
      {
         this->custData = backupData;
         inTxn = false;
         Console::WriteLine( "CancelEdit - {0}", this->custData->lastName );
      }

      Console::WriteLine( "End CancelEdit" );
   }

   virtual void EndEdit()
   {
      Console::WriteLine( "Start EndEdit{0}{1}", this->custData->id, this->custData->lastName );
      if ( inTxn )
      {
         backupData = gcnew CustomerData;
         inTxn = false;
         Console::WriteLine( "Done EndEdit - {0}{1}", this->custData->id, this->custData->lastName );
      }

      Console::WriteLine( "End EndEdit" );
   }


public:

   Customer( String^ ID )
   {
      this->custData = gcnew CustomerData;
      this->custData->id = ID;
      this->custData->firstName = "";
      this->custData->lastName = "";
      inTxn = false;
   }

   property String^ ID 
   {
      String^ get()
      {
         return this->custData->id;
      }

   }

   property String^ FirstName 
   {
      String^ get()
      {
         return this->custData->firstName;
      }

      void set( String^ value )
      {
         this->custData->firstName = value;
         this->OnCustomerChanged();
      }

   }

   property String^ LastName 
   {
      String^ get()
      {
         return this->custData->lastName;
      }

      void set( String^ value )
      {
         this->custData->lastName = value;
         this->OnCustomerChanged();
      }

   }

internal:

   property CustomersList^ Parent 
   {
      CustomersList^ get()
      {
         return parent;
      }

      void set( CustomersList^ value )
      {
         parent = value;
      }

   }

   void OnCustomerChanged()
   {
      if (!inTxn && Parent != nullptr)
      {
          Parent->CustomerChanged(this);
      }
   }

public:
   virtual String^ ToString() override
   {
      StringWriter^ sb = gcnew StringWriter;
      sb->Write( this->FirstName );
      sb->Write( " " );
      sb->Write( this->LastName );
      return sb->ToString();
   }
};

public class Customer : IEditableObject
{
    struct CustomerData
    {
        internal string id;
        internal string firstName;
        internal string lastName;
    }

    CustomerData custData;
    CustomerData backupData;
    bool inTxn;

    // Implements IEditableObject
    void IEditableObject.BeginEdit()
    {
        Console.WriteLine("Start BeginEdit");
        if (!inTxn)
        {
            backupData = custData;
            inTxn = true;
            Console.WriteLine("BeginEdit - " + backupData.lastName);
        }
        Console.WriteLine("End BeginEdit");
    }

    void IEditableObject.CancelEdit()
    {
        Console.WriteLine("Start CancelEdit");
        if (inTxn)
        {
            custData = backupData;
            inTxn = false;
            Console.WriteLine("CancelEdit - " + custData.lastName);
        }
        Console.WriteLine("End CancelEdit");
    }

    void IEditableObject.EndEdit()
    {
        Console.WriteLine("Start EndEdit" + custData.id + custData.lastName);
        if (inTxn)
        {
            backupData = new CustomerData();
            inTxn = false;
            Console.WriteLine("Done EndEdit - " + custData.id + custData.lastName);
        }
        Console.WriteLine("End EndEdit");
    }

    public Customer(string ID) : base() => custData = new CustomerData
    {
        id = ID,
        firstName = "",
        lastName = ""
    };

    public string ID => custData.id;

    public string FirstName
    {
        get => custData.firstName;
        set
        {
            custData.firstName = value;
            OnCustomerChanged();
        }
    }

    public string LastName
    {
        get => custData.lastName;
        set
        {
            custData.lastName = value;
            OnCustomerChanged();
        }
    }

    internal CustomersList Parent { get; set; }

    void OnCustomerChanged()
    {
        if (!inTxn && Parent != null)
        {
            Parent.CustomerChanged(this);
        }
    }

    public override string ToString()
    {
        StringWriter sb = new();
        sb.Write(FirstName);
        sb.Write(" ");
        sb.Write(LastName);
        return sb.ToString();
    }
}

Public Class Customer
    Implements IEditableObject

    Structure CustomerData
        Friend id As String
        Friend firstName As String
        Friend lastName As String
    End Structure 

    Public parent As CustomersList
    Private custData As CustomerData
    Private backupData As CustomerData
    Private inTxn As Boolean = False


    ' Implements IEditableObject
    Sub BeginEdit() Implements IEditableObject.BeginEdit
        Console.WriteLine("Start BeginEdit")
        If Not inTxn Then
            Me.backupData = custData
            inTxn = True
            Console.WriteLine(("BeginEdit - " + Me.backupData.lastName))
        End If
        Console.WriteLine("End BeginEdit")
    End Sub 


    Sub CancelEdit() Implements IEditableObject.CancelEdit
        Console.WriteLine("Start CancelEdit")
        If inTxn Then
            Me.custData = backupData
            inTxn = False
            Console.WriteLine(("CancelEdit - " + Me.custData.lastName))
        End If
        Console.WriteLine("End CancelEdit")
    End Sub 


    Sub EndEdit() Implements IEditableObject.EndEdit
        Console.WriteLine(("Start EndEdit" + Me.custData.id + Me.custData.lastName))
        If inTxn Then
            backupData = New CustomerData()
            inTxn = False
            Console.WriteLine(("Done EndEdit - " + Me.custData.id + Me.custData.lastName))
        End If
        Console.WriteLine("End EndEdit")
    End Sub 


    Public Sub New(ByVal ID As String)
        Me.custData = New CustomerData()
        Me.custData.id = ID
        Me.custData.firstName = ""
        Me.custData.lastName = ""
    End Sub 


    Public ReadOnly Property ID() As String
        Get
            Return Me.custData.id
        End Get
    End Property


    Public Property FirstName() As String
        Get
            Return Me.custData.firstName
        End Get
        Set(ByVal Value As String)
            Me.custData.firstName = Value
            Me.OnCustomerChanged()
        End Set
    End Property


    Public Property LastName() As String
        Get
            Return Me.custData.lastName
        End Get
        Set(ByVal Value As String)
            Me.custData.lastName = Value
            Me.OnCustomerChanged()
        End Set
    End Property


    Friend Property Parents() As CustomersList
        Get
            Return Parent
        End Get
        Set(ByVal Value As CustomersList)
            parent = Value
        End Set
    End Property


    Private Sub OnCustomerChanged()
        If Not inTxn And (Parent IsNot Nothing) Then
            Parent.CustomerChanged(Me)
        End If
    End Sub 

    
    Public Overrides Function ToString() As String
        Dim sb As New StringWriter()
        sb.Write(Me.FirstName)
        sb.Write(" ")
        sb.Write(Me.LastName)
        Return sb.ToString()
    End Function 
End Class

Kommentarer

Det här gränssnittet används vanligtvis för att avbilda BeginEdit, EndEditoch CancelEdit semantik för en DataRowView.

Metoder

Name	Description
BeginEdit()	Påbörjar en redigering av ett objekt.
CancelEdit()	Tar bort ändringar sedan det senaste BeginEdit() anropet.
EndEdit()	Push-överför ändringar sedan det senaste BeginEdit() eller AddNew() anropet till det underliggande objektet.