AppearanceAttribute.AppearanceItemType Property

Specifies the type of UI elements affected by the conditional appearance rule created using this attribute.

Namespace: DevExpress.ExpressApp.ConditionalAppearance

Assembly: DevExpress.Persistent.Base.v23.1.dll

NuGet Package: DevExpress.Persistent.Base

Declaration

C#

public string AppearanceItemType { get; set; }

VB.NET

Public Property AppearanceItemType As String

Property Value

Type	Description
String	The string representation of an AppearanceItemType enumeration value specifying the type of UI elements affected by the conditional appearance rule.

Remarks

To specify the UI element to be affected, apply the Appearance attribute to the required business class or business class property and use the AppearanceItemType and AppearanceAttribute.TargetItems attribute parameters. For details, refer to the Declare Conditional Appearance Rules in Code topic.

These are the following possible values for the AppearanceItemType attribute parameter:

• AppearanceItemType.ViewItem

  If the AppearanceItemType parameter is set to this value, the rule generated using this attribute affects the property(ies) specified by the AppearanceAttribute.TargetItems attribute parameter. In dependence of the AppearanceAttribute.Context parameter, the property(ies) are affected in List Views and/or Detail Views. In List Views, the rule affects the corresponding cells both in view and edit mode. In Detail Views, the rule affects the corresponding Property Editors. Static Text Detail View Items can be affected as well.

  Note that currently, only Grid List Editors and Tree List Editors for Windows Forms and ASP.NET Web Forms applications support conditional appearance.

• AppearanceItemType.LayoutItem

  If the AppearanceItemType parameter is set to this value, the rule generated using this attribute affects the Layout Item(s), Groups() and Tabbed Group(s) specified by the AppearanceAttribute.TargetItems attribute parameter.

• AppearanceItemType.Action

  If the AppearanceItemType parameter is set to this value, the rule generated using this attribute affects the Action(s) specified by the AppearanceAttribute.TargetItems attribute parameter.

By default, this property is set to ViewItem.

Examples

Example 1.

According to the rule demonstrated in the example below, the Product objects whose Price is more than 50 will be displayed in Red background using Maroon font color in List Views.

C# (EF Core)

using DevExpress.ExpressApp.ConditionalAppearance;
//...
[Appearance("RedPriceObject", AppearanceItemType = "ViewItem", TargetItems = "*",
    Criteria = "Price>50", Context = "ListView", BackColor = "Red",
        FontColor = "Maroon", Priority = 2)]
public class Product : BaseObject {
    public virtual string Name { get; set; }
    public virtual decimal Price { get; set; }
    public virtual ProductStatus Status { get; set; }
    public virtual Category Category { get; set; }
}

// Make sure that you use options.UseChangeTrackingProxies() in your DbContext settings.

C# (XPO)

using DevExpress.ExpressApp.ConditionalAppearance;
//...
[Appearance("RedPriceObject", AppearanceItemType = "ViewItem", TargetItems = "*",
    Criteria = "Price>50", Context = "ListView", BackColor = "Red",
        FontColor = "Maroon", Priority = 2)]
public class Product : BaseObject {
    public Product(Session session) : base(session) { }
    public string Name {
        //...
    }
    public decimal Price {
        //...
    }
    public ProductStatus Status {
        //...
    }
    public Category Category {
        //...
    }
}

VB.NET (XPO)

Imports DevExpress.ExpressApp.ConditionalAppearance
'...
<Appearance("RedPriceObject", AppearanceItemType := "ViewItem", TargetItems := "*", _
Criteria := "Price>50", Context := "ListView", BackColor := "Red", _
FontColor := "Maroon", Priority := 2)> _
Public Class Product
        Inherits BaseObject
    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub
    Public ReadOnly Property Name() As String
        '...
    End Property
    Public ReadOnly Property Price() As Decimal
        '...
    End Property
    Public ReadOnly Property Status() As ProductStatus
        '...
    End Property
    Public ReadOnly Property Category() As Category
        '...
    End Property
End Class

Example 2.

According to the rule demonstrated in the example below, the Category layout item’s caption in Product Detail Views will be displayed in Blue font color when the Category property value is “Seafood”.

C# (EF Core)

using DevExpress.ExpressApp.ConditionalAppearance;
//...
public class Product : BaseObject {
    [Appearance("CategoryColoredInDetailView", AppearanceItemType = "LayoutItem",
         TargetItems = "Category", Criteria = "Category = 'Seafood'", Context = "DetailView",
             FontColor = "Blue")]
    public virtual Category Category { get; set; }
}

[DefaultProperty(nameof(Name))]
public class Category : BaseObject {
    public virtual string Name { get; set; }
}

// Make sure that you use options.UseChangeTrackingProxies() in your DbContext settings.

C# (XPO)

using DevExpress.ExpressApp.ConditionalAppearance;
//...
public class Product : BaseObject {
    public Product(Session session) : base(session) { }
    [Appearance("CategoryColoredInDetailView", AppearanceItemType = "LayoutItem",
         TargetItems = "Category", Criteria = "Category = 'Seafood'", Context = "DetailView",
             FontColor = "Blue")]
    public Category Category {
        //...
    }
}
[DefaultProperty(nameof(Name))]
public class Category : BaseObject {
    public Category(Session session) : base(session) {}
    public string Name {
        //...
    }
}

VB.NET (XPO)

Imports DevExpress.ExpressApp.ConditionalAppearance
'...
Public Class Product
        Inherits BaseObject
    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub
    <Appearance("CategoryColoredInDetailView", AppearanceItemType := "LayoutItem", _
    TargetItems := "Category", Criteria := "Category = 'Seafood'", _
    Context := "DetailView", FontColor := "Blue")> _
    Public ReadOnly Property Category() As Category
        '...
    End Property
End Class
<DefaultProperty(NameOf(Name))> _
Public Class Category
        Inherits BaseObject
    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub
    Public ReadOnly Property Name() As String
        '...
    End Property
End Class

Example 3.

According to the rule demonstrated in the example below, a Product’s Deactivate Action will be disabled when the Status property is set to “Inactive” in all Product Views. Note that the Action ID specified in this rule contains the class name (“Product.Deactivate”), because the Deactivate Action is declared using the ActionAttribute. If an Action is declared in a Controller, specify its ID without the class name, e.g., “Delete” or “Unlink”.

C# (EF Core)

using DevExpress.ExpressApp.ConditionalAppearance;
//...
[Appearance("ActionState", AppearanceItemType = "Action",
    TargetItems = "Product.Deactivate",
        Criteria = "Status = 'Inactive'", Context = "Any", Enabled = false)]
public class Product : BaseObject {
    public virtual ProductStatus Status { get; set; }
    [Action(PredefinedCategory.RecordEdit, Caption = "Deactivate Product...", AutoCommit = true,
     TargetObjectsCriteria = "Status = 'Active'",
      SelectionDependencyType = MethodActionSelectionDependencyType.RequireSingleObject)]
    public void Deactivate() {
        Status = ProductStatus.Inactive;
    }
}

// Make sure that you use options.UseChangeTrackingProxies() in your DbContext settings.

C# (XPO)

using DevExpress.ExpressApp.ConditionalAppearance;
//...
[Appearance("ActionState", AppearanceItemType = "Action",
    TargetItems = "Product.Deactivate",
        Criteria = "Status = 'Inactive'", Context = "Any", Enabled = false)]
public class Product : BaseObject {
    public Product(Session session) : base(session) { }
    public ProductStatus Status {
        //...
    }   
    [Action(PredefinedCategory.RecordEdit, Caption = "Deactivate Product...", AutoCommit = true,
     TargetObjectsCriteria = "Status = 'Active'",
      SelectionDependencyType = MethodActionSelectionDependencyType.RequireSingleObject)]
    public void Deactivate() {
        Status = ProductStatus.Inactive;
    }
}

VB.NET (XPO)

Imports DevExpress.ExpressApp.ConditionalAppearance
'...
<Appearance("ActionState", AppearanceItemType := "Action", _
TargetItems := "Product.Deactivate", _
Criteria := "Status = 'Inactive'", Context := "Any", Enabled := False)> _
Public Class Product
        Inherits BaseObject
    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub
    Public ReadOnly Property Status() As ProductStatus
        '...
    End Property
    <Action(PredefinedCategory.RecordEdit, Caption := "Deactivate Product...", AutoCommit := True,
    TargetObjectsCriteria := "Status = 'Active'", _
    SelectionDependencyType := MethodActionSelectionDependencyType.RequireSingleObject)> _
    Public Sub Deactivate()
        Status = ProductStatus.Inactive
    End Sub
End Class

There are more examples demonstrated in the Declare Conditional Appearance Rules in Code topic. See these examples in the Feature Center demo installed with the eXpressApp Framework in the %PUBLIC%\Documents\DevExpress Demos 23.1\Components\XAF\FeatureCenter.NETFramework.XPO folder, or refer to the Feature Center demo online.

Implements

AppearanceItemType