ImageEditorAttribute Class

Applied to business class properties of the byte array type. Specifies that the target property persists an image. Attribute parameters specify settings to be used by Image Property Editors when displaying images persisted by the target property.

Namespace: DevExpress.Persistent.Base

Assembly: DevExpress.ExpressApp.v24.1.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, Inherited = true, AllowMultiple = false)]
public class ImageEditorAttribute :
    ModelExportedValuesAttribute

VB.NET

<AttributeUsage(AttributeTargets.Property Or AttributeTargets.Field, Inherited:=True, AllowMultiple:=False)>
Public Class ImageEditorAttribute
    Inherits ModelExportedValuesAttribute

Remarks

By default, byte[] properties are displayed via Default Property Editor as a collection of bytes. If the ImageEditorAttribute attribute is applied, Image Property Editors are used. The ImagePropertyEditor is used in XAF Windows Forms applications, the ASPxImagePropertyEditor is used in XAF ASP.NET Web Forms applications. These Property Editors are instantiated using default settings when the ImageEditorAttribute attribute is applied without parameters. However, it is often necessary to specify different settings for the Property Editors that display images represented by different properties. To do this, pass the settings as the parameters. This will make all the Image Property Editors use the specified settings when displaying images.

Basically, there are two groups of settings - the settings that affect the Image Property Editors used in Detail Views and the settings that affect the inplace Image Property Editors used in List Views. The following table lists the ImageEditorAttribute class’ public properties that can be passed as named parameters in the attribute’s constructor:

Name	Description
ImageEditorAttribute.DetailViewImageEditorFixedHeight	Specifies the fixed height of Image Property Editors in Detail Views.
ImageEditorAttribute.DetailViewImageEditorFixedWidth	Specifies the fixed width of Image Property Editors in Detail Views.
ImageEditorAttribute.DetailViewImageEditorMode	Specifies how images represented by the target Image property must be displayed in Detail Views.
ImageEditorAttribute.ImageSizeMode	Specifies how images represented by the target Image property must be resized in Image Property Editors.
ImageEditorAttribute.ListViewImageEditorCustomHeight	Specifies the height of inplace Image Property Editors in List Views.
ImageEditorAttribute.ListViewImageEditorMode	Specifies how images represented by the target Image property must be displayed in List Views.

These parameters have the corresponding properties in the Application Model‘s IModelMember node. When the ImageEditorAttribute is applied to a property, the parameter’s values are assigned to the Application Model’s property of the node that represents the target property. These Application Model properties values, in turn, are set to the relative properties of the IModelColumn and IModelPropertyEditor nodes that also correspond to the target property.

The following code snippets demonstrate the ImageEditorAttribute usage.

• All the Property Editors that represent the Photo property will display images in drop-down windows:

  C# (EF Core)

  using System.Drawing;  
  //...
  public class Contact : BaseObject {
      //...        
      [ImageEditor(ListViewImageEditorMode = ImageEditorMode.DropDownPictureEdit, 
          DetailViewImageEditorMode = ImageEditorMode.DropDownPictureEdit)]
      public virtual byte[] Photo { get; set; }
      //...
  }
  
  // Make sure that you use options.UseChangeTrackingProxies() in your DbContext settings.
  

  C# (XPO)

  using System.Drawing;
  using DevExpress.Persistent.Base;
  
  //...
  
  public class Contact : BaseObject {
  //...
  
      [ImageEditor(ListViewImageEditorMode = ImageEditorMode.DropDownPictureEdit, 
          DetailViewImageEditorMode = ImageEditorMode.DropDownPictureEdit)]
      public byte[] Photo {
          get { return GetPropertyValue<byte[]>(nameof(Photo)); }
          set { SetPropertyValue<byte[]>(nameof(Photo), value); }
      }
  
  //...
  }
  

  VB.NET (XPO)

  Imports System.Drawing
  Imports DevExpress.Persistent.Base
  
  '...
  
  Public Class Contact
    Inherits BaseObject
  '...
      <ImageEditor(ListViewImageEditorMode := ImageEditorMode.DropDownPictureEdit, _
      DetailViewImageEditorMode := ImageEditorMode.DropDownPictureEdit)> _
      Public Property Photo() As Byte()
          Get
              Return GetPropertyValue(Of Byte())(NameOf(Photo))
          End Get
          Set(ByVal value As Image)
              SetPropertyValue(Of Byte())(NameOf(Photo), value)
          End Set
      End Property
  '...
  End Class
  

• All the Property Editors that represent the Photo property in Detail Views will have a fixed width of 40 pixels :

  C# (EF Core)

  using System.Drawing;
  //...
  public class Contact : BaseObject {
      //...
  
      [ImageEditor(DetailViewImageEditorMode = ImageEditorMode.PictureEdit, 
          DetailViewImageEditorFixedWidth = 40)]
      public virtual byte[] Photo { get; set; }
      //...
  }
  
  // Make sure that you use options.UseChangeTrackingProxies() in your DbContext settings.
  

  C# (XPO)

  using System.Drawing;
  using DevExpress.Persistent.Base;
  //...
  public class Contact : BaseObject {
  //...
  
      [ImageEditor(DetailViewImageEditorMode = ImageEditorMode.PictureEdit, 
          DetailViewImageEditorFixedWidth = 40)]
      public byte[] Photo {
          get { return GetPropertyValue<byte[]>(nameof(Photo)); }
          set { SetPropertyValue<byte[]>(nameof(Photo), value); }
      }
  //...
  }
  

  VB.NET (XPO)

  Imports System.Drawing
  Imports DevExpress.Persistent.Base
  
  '...
  
  Public Class Contact
    Inherits BaseObject
  '...
  
      <ImageEditor(DetailViewImageEditorMode := ImageEditorMode.PictureEdit, _
      DetailViewImageEditorFixedWidth := 40)> _
      Public Property Photo() As Byte()
          Get
              Return GetPropertyValue(Of Byte())(NameOf(Photo))
          End Get
          Set(ByVal value As Image)
              SetPropertyValue(Of Byte())(NameOf(Photo), value)
          End Set
      End Property
  
  '...
  End Class
  

Inheritance

Object

Attribute

DevExpress.Persistent.Base.ModelExportedValuesAttribute

ImageEditorAttribute