DataListDesigner 類別

定義

public ref class DataListDesigner : System::Web::UI::Design::WebControls::BaseDataListDesigner

public class DataListDesigner : System.Web.UI.Design.WebControls.BaseDataListDesigner

[System.Web.UI.Design.SupportsPreviewControl(true)]
public class DataListDesigner : System.Web.UI.Design.WebControls.BaseDataListDesigner

type DataListDesigner = class
    inherit BaseDataListDesigner

[<System.Web.UI.Design.SupportsPreviewControl(true)>]
type DataListDesigner = class
    inherit BaseDataListDesigner

Public Class DataListDesigner
Inherits BaseDataListDesigner

繼承

Object

ComponentDesigner

HtmlControlDesigner

ControlDesigner

TemplatedControlDesigner

BaseDataListDesigner

DataListDesigner

屬性

SupportsPreviewControlAttribute

範例

以下程式碼範例示範如何擴充該 DataListDesigner 類別。 若啟用控制項，程式碼會 GetDesignTimeHtml 覆寫顯示紫色五點邊框 DataList 的方法。

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

namespace ASPNET.Examples.CS
{
    [SecurityPermission( 
    SecurityAction.Demand, 
    Flags = SecurityPermissionFlag.UnmanagedCode)] 
    public class SimpleGridViewDesigner : GridViewDesigner
    {
        private SimpleGridView simpleGView;

        public override string GetDesignTimeHtml()
        {
            string designTimeHtml = String.Empty;

            simpleGView = (SimpleGridView)Component;

            // Check the control's BorderStyle property to  
            // conditionally render design-time HTML.
            if (simpleGView.BorderStyle == BorderStyle.NotSet)
            {
                // Save the current property settings in variables.
                int oldCellPadding = simpleGView.CellPadding;
                Unit oldBorderWidth = simpleGView.BorderWidth;
                Color oldBorderColor = simpleGView.BorderColor;

                // Set properties and generate the design-time HTML.
                try
                {
                    simpleGView.Caption = "SimpleGridView";
                    simpleGView.CellPadding = 1;
                    simpleGView.BorderWidth = Unit.Pixel(3);
                    simpleGView.BorderColor = Color.Red;

                    designTimeHtml = base.GetDesignTimeHtml();
                }
                catch (Exception ex)
                {
                    // Get HTML from the GetErrorDesignTimeHtml 
                    // method if an exception occurs.
                    designTimeHtml = GetErrorDesignTimeHtml(ex);

                    // Return the properties to their original values.
                }
                finally
                {
                    simpleGView.CellPadding = oldCellPadding;
                    simpleGView.BorderWidth = oldBorderWidth;
                    simpleGView.BorderColor = oldBorderColor;
                }
            }
            else
            {
                designTimeHtml = base.GetDesignTimeHtml();
            }

            return designTimeHtml;
        }

        protected override string
            GetErrorDesignTimeHtml(System.Exception exc)
        {
            return CreatePlaceHolderDesignTimeHtml(
                "ASPNET.Examples: An error occurred while rendering the GridView.");
        }

        public override void Initialize(IComponent component)
        {
            simpleGView = (SimpleGridView)component;
            base.Initialize(component);
        }
    }
}

Imports System.Drawing
Imports System.ComponentModel
Imports System.Web.UI.WebControls
Imports System.Security
Imports System.Web.UI.Design
Imports System.Web.UI.Design.WebControls

Namespace ASPNET.Examples
    < _
        Designer("ASPNET.Examples.Design.SimpleGridViewDesigner", _
            "System.Web.UI.Design.GridViewDesigner") _
    > _
    Public Class SimpleGridView
        Inherits GridView

        ' Code to customize your GridView goes here

    End Class
End Namespace

Namespace ASPNET.Examples.Design
    <Permissions.SecurityPermission( _
    Permissions.SecurityAction.Demand, _
    Flags:=Permissions.SecurityPermissionFlag.UnmanagedCode)> _
    Public Class SimpleGridViewDesigner
        Inherits GridViewDesigner

        Private simpleGView As SimpleGridView

        Public Overrides Function GetDesignTimeHtml() As String
            Dim designTimeHtml As String = String.Empty

            simpleGView = CType(Component, SimpleGridView)

            ' Check the control's BorderStyle property to  
            ' conditionally render design-time HTML.
            If (simpleGView.BorderStyle = BorderStyle.NotSet) Then
                ' Save the current property settings in variables.
                Dim oldCellPadding As Integer = simpleGView.CellPadding
                Dim oldBorderWidth As Unit = simpleGView.BorderWidth
                Dim oldBorderColor As Color = simpleGView.BorderColor

                ' Set properties and generate the design-time HTML.
                Try
                    simpleGView.Caption = "SimpleGridView"
                    simpleGView.CellPadding = 1
                    simpleGView.BorderWidth = Unit.Pixel(3)
                    simpleGView.BorderColor = Color.Red

                    designTimeHtml = MyBase.GetDesignTimeHtml()

                Catch ex As Exception
                    ' Get HTML from the GetErrorDesignTimeHtml 
                    ' method if an exception occurs.
                    designTimeHtml = GetErrorDesignTimeHtml(ex)

                    ' Return the properties to their original values.
                Finally
                    simpleGView.CellPadding = oldCellPadding
                    simpleGView.BorderWidth = oldBorderWidth
                    simpleGView.BorderColor = oldBorderColor
                End Try

            Else
                designTimeHtml = MyBase.GetDesignTimeHtml()
            End If

            Return designTimeHtml
        End Function

        Protected Overrides Function _
            GetErrorDesignTimeHtml(ByVal exc As Exception) As String

            Return CreatePlaceHolderDesignTimeHtml( _
                "ASPNET.Examples: An error occurred while rendering the GridView.")

        End Function

        Public Overrides Sub Initialize(ByVal component As IComponent)

            simpleGView = CType(component, SimpleGridView)

            MyBase.Initialize(component)

        End Sub
    End Class
End Namespace

以下程式碼範例展示了如何利用 將 DesignerAttribute 設計者與 DataList 控制項關聯起來。

[ Designer("ASPNET.Examples.Design.SimpleGridViewDesigner", 
        "System.Web.UI.Design.GridViewDesigner")]
public class SimpleGridView : GridView
{
    // Code to customize your GridView goes here
}

< _
    Designer("ASPNET.Examples.Design.SimpleGridViewDesigner", _
        "System.Web.UI.Design.GridViewDesigner") _
> _
Public Class SimpleGridView
    Inherits GridView

    ' Code to customize your GridView goes here

End Class

另請參閱

• DataList
• DataListComponentEditor
• ASP.NET 控制設計師概述
• 攻略：建立網頁伺服器控制的基本控制設計器
• 提供 Design-Time 支持
• 如何：擴展設計模式下控制項的外觀與行為