WebPartDesigner Classe

Definição

public ref class WebPartDesigner : System::Web::UI::Design::WebControls::WebParts::PartDesigner

public class WebPartDesigner : System.Web.UI.Design.WebControls.WebParts.PartDesigner

type WebPartDesigner = class
    inherit PartDesigner

Public Class WebPartDesigner
Inherits PartDesigner

Herança

Object

ComponentDesigner

HtmlControlDesigner

ControlDesigner

CompositeControlDesigner

PartDesigner

WebPartDesigner

Exemplos

O exemplo de código a seguir mostra a interação entre um WebPart controle e seu associado WebPartDesigner. O WebPart controle contém um Calendar controle do qual o usuário final seleciona seu aniversário, um Button controle para enviar a seleção e um Label controle para exibir uma mensagem no aniversário do usuário. O WebPartDesigner verifica se o controle associado é do tipo esperado e, em seguida, personaliza a renderização em tempo de design do controle dito. Observe que as personalizações visuais do designer são visíveis somente no momento do design, enquanto as do controle associado ficam visíveis no tempo de execução e no tempo de design.

Todos os métodos substituídos neste exemplo derivam da ControlDesigner classe base. Para outros membros disponíveis e seu uso, consulte System.Web.UI.Design.ControlDesigner.

using System;
using System.Security.Permissions;
using System.Web;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.Design.WebControls.WebParts;
using System.ComponentModel;

/// <summary>
/// BirthdayPart demonstrates some of the most
/// common overrides of members of the WebPart
/// class. BirthdayPartDesigner shows how to 
/// customize the rendering of a custom WebPart
/// control.
/// </summary>
namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, 
    Level=AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand, 
    Level=AspNetHostingPermissionLevel.Minimal)]
  [Designer(typeof(BirthdayPartDesigner))]
  public class BirthdayPart : WebPart
  {
    private DateTime birthDate;
    Calendar input;
    Label displayContent;

    public BirthdayPart()
    {
      this.AllowClose = false;
      this.Title = "Enter your birthday";
    }

    [
      Personalizable(PersonalizationScope.User, true),
      WebBrowsable()
    ]
    public DateTime BirthDate
    {
      get { return birthDate; }
      set { birthDate = value; }
    }
    
    // Set the appearance of the control at run time.
    protected override void CreateChildControls()
    {
      Controls.Clear();
      input = new Calendar();
      this.Controls.Add(input);
      Button update = new Button();
      update.Text = "Submit";
      update.Click += new EventHandler(this.submit_Click);
      this.Controls.Add(update);
      displayContent = new Label();
      displayContent.BackColor = 
      System.Drawing.Color.LightBlue;
      Literal br = new Literal();
      br.Text = "<br />";
      if ((this.birthDate.Day == DateTime.Now.Day)
        && (this.birthDate.Month == DateTime.Now.Month))
      {
        displayContent.Text = "Happy Birthday!";
        this.Controls.Add(br);
        this.Controls.Add(displayContent);
      }
    }

    private void submit_Click(object sender, EventArgs e)
    {
      this.birthDate = input.SelectedDate;
    }
  }

  public class BirthdayPartDesigner : WebPartDesigner
  {
    public override void Initialize(IComponent component)
    {
      // Verify that the associated control is a BirthdayPart.
      if (!typeof(BirthdayPart).IsInstanceOfType(component))
      {
        throw new ArgumentException("The specified control is not of type 'BirthdayPart'", "component");
      }
      base.Initialize(component);
    }

    // Here is where you make customizations
    // to design time appearance that will not
    // be visible to the end user.
    public override string GetDesignTimeHtml()
    {
      string designTimeHtml = null;
      try
      {
        designTimeHtml = base.GetDesignTimeHtml();
        string s = "<hr /><hr />I just added these lines to the"
          + " bottom of the control.<hr /><hr /></div>";
        designTimeHtml = designTimeHtml.Replace("</div>", s);
      }
      catch (Exception ex)
      {
        designTimeHtml = GetErrorDesignTimeHtml(ex);
      }
      finally
      {
        // undo any changes in the try block
      }

      if ((designTimeHtml == null) || (designTimeHtml.Length == 0))
      {
        designTimeHtml = GetEmptyDesignTimeHtml();
      }
      return designTimeHtml;
    }

    // This method normally returns a blank string.
    // Override to return a meaningful message.
    protected override string GetEmptyDesignTimeHtml()
    {
      return CreatePlaceHolderDesignTimeHtml(
        "<hr />If the page developer forgot to fill in a " +
        "required property you could tell them here.<hr />");
    }
    
    // Add specific text to the generic error message.
    protected override string GetErrorDesignTimeHtml(Exception e)
    {
      string s = "<hr />The control failed to render.";
      return(s + e.Message + "<hr />");
    }
  }
}

Imports System.Security.Permissions
Imports System.Web
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.Design.WebControls.WebParts
Imports System.ComponentModel

' BirthdayPart demonstrates some of the most
' common overrides of members of the WebPart
' class. BirthdayPartDesigner shows how to 
' customize the rendering of a custom WebPart
' control.
Namespace Samples.AspNet.VB.Controls
    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    <AspNetHostingPermission(SecurityAction.InheritanceDemand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    <Designer(GetType(BirthdayPartDesigner))> _
    Public Class BirthdayPart
        Inherits WebPart
        Private m_birthDate As DateTime
        Private input As Calendar
        Private displayContent As Label

        Public Sub New()
            Me.AllowClose = False
            Me.Title = "Enter your birthday"
        End Sub

        <Personalizable(PersonalizationScope.User, True), WebBrowsable()> _
        Public Property BirthDate() As DateTime
            Get
                Return m_birthDate
            End Get
            Set(value As DateTime)
                m_birthDate = value
            End Set
        End Property

        ' Set the appearance of the control at run time.
        Protected Overrides Sub CreateChildControls()
            Controls.Clear()
            input = New Calendar()
            Me.Controls.Add(input)
            Dim update As New Button()
            update.Text = "Submit"
            AddHandler update.Click, New EventHandler(AddressOf Me.submit_Click)
            Me.Controls.Add(update)
            displayContent = New Label()
            displayContent.BackColor = System.Drawing.Color.LightBlue
            Dim br As New Literal()
            br.Text = "<br />"
            If (Me.m_birthDate.Day = DateTime.Now.Day) AndAlso (Me.m_birthDate.Month = DateTime.Now.Month) Then
                displayContent.Text = "Happy Birthday!"
                Me.Controls.Add(br)
                Me.Controls.Add(displayContent)
            End If
        End Sub

        Private Sub submit_Click(sender As Object, e As EventArgs)
            Me.m_birthDate = input.SelectedDate
        End Sub
    End Class

    Public Class BirthdayPartDesigner
        Inherits WebPartDesigner
        Public Overrides Sub Initialize(component As IComponent)
            ' Verify that the associated control is a BirthdayPart.
            If Not GetType(BirthdayPart).IsInstanceOfType(component) Then
                Throw New ArgumentException("The specified control is not of type 'BirthdayPart'", "component")
            End If
            MyBase.Initialize(component)
        End Sub

        ' Here is where you make customizations
        ' to design time appearance that will not
        ' be visible to the end user.
        Public Overrides Function GetDesignTimeHtml() As String
            Dim designTimeHtml As String = Nothing
            Try
                designTimeHtml = MyBase.GetDesignTimeHtml()
                Dim s As String = "<hr /><hr />I just added these lines to the" & " bottom of the control.<hr /><hr /></div>"
                designTimeHtml = designTimeHtml.Replace("</div>", s)
            Catch ex As Exception
                designTimeHtml = GetErrorDesignTimeHtml(ex)
                ' undo any changes in the try block
            Finally
            End Try

            If (designTimeHtml Is Nothing) OrElse (designTimeHtml.Length = 0) Then
                designTimeHtml = GetEmptyDesignTimeHtml()
            End If
            Return designTimeHtml
        End Function

        ' This method normally returns a blank string.
        ' Override to return a meaningful message.
        Protected Overrides Function GetEmptyDesignTimeHtml() As String
            Return CreatePlaceHolderDesignTimeHtml("<hr />If the page developer forgot to fill in a " & "required property you could tell them here.<hr />")
        End Function

        ' Add specific text to the generic error message.
        Protected Overrides Function GetErrorDesignTimeHtml(e As Exception) As String
            Dim s As String = "<hr />The control failed to render."
            Return (s & e.Message & "<hr />")
        End Function
    End Class
End Namespace

Comentários

A WebPartDesigner classe fornece a representação visual para WebPart controles em tempo de design. Ele é derivado da PartDesigner classe e adiciona validação para verificar se o controle associado é um WebPart controle ou tipo derivado.

WebPartDesigner herda uma UsePreviewControl propriedade de seu pai que é sempre definida como true. Isso faz com que o ambiente de design visual gere um View controle para manter uma cópia temporária da superfície de WebPart design; essa cópia é então mantida na marcação. Se você substituir a UsePreviewControl propriedade a ser retornada false, o ambiente de design visual gerará marcação diretamente do controle real WebPart .

Os designers de Web Parts geralmente agem muito como designers de controle regulares; os métodos principais para definir a aparência em tempo de design derivam da ControlDesigner classe. Especificamente, você pode substituir o GetDesignTimeHtml método para alterar a marcação de tempo de design associada ao controle. Você também pode substituir os métodos e GetEmptyDesignTimeHtml os GetErrorDesignTimeHtml métodos para lidar com erros e cadeias de caracteres vazias (""), respectivamente.

Confira também

• ControlDesigner
• controles de Web Parts ASP.NET
• Visão geral dos designers de controle de ASP.NET