ControlBuilder 类
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
支持页分析器生成控件及其包含的子控件。
public ref class ControlBuilderpublic class ControlBuildertype ControlBuilder = classPublic Class ControlBuilder- 继承
-
ControlBuilder
- 派生
示例
下面的代码示例创建一个 Table 控件，该控件的属性和内容是在生成表时定义的。 下面是用于生成可执行文件的命令行。
vbc /r:System.dll /r:System.Web.dll /r:System.Drawing.dll /t:library /out:myWebAppPath/Bin/vb_mycontrolbuilder.dll myControlBuilder.vb
csc /t:library /out:myWebAppPath/Bin/cs_mycontrolbuilder.dll myControlBuilder.cs
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections;
using System.Drawing;
using System.Security.Permissions;
namespace CustomControls
{
[AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal)]
public class MyTableCell : TableCell, INamingContainer { };
[AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal)]
public class MyCell
/*
* Class name: MyCell.
* Declares the class for the child controls to include in the control collection.
*/
{
string _id;
string _value;
Color _backColor;
public string CellID
{
get
{ return _id; }
set
{ _id = value; }
}
public string Text
{
get
{ return _value; }
set
{ _value = value; }
}
public Color BackColor
{
get
{ return _backColor; }
set
{ _backColor = value; }
}
};
[AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal)]
public class MyControlBuilder : ControlBuilder
{
public override Type GetChildControlType(string tagName, IDictionary attribs)
{
// Allows TableRow without "runat=server" attribute to be added to the collection.
if (String.Compare(tagName, "mycell", true) == 0)
return typeof(MyCell);
return null;
}
public override void AppendLiteralString(string s)
{
// Ignores literals between rows.
}
}
[AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal)]
[ControlBuilderAttribute(typeof(MyControlBuilder))]
public class MyCS_CustomControl : Control, INamingContainer
/*
* Class name: MyCS_CustomControl.
* Processes the element declarations within a control declaration.
* This builds the actual control.
*/
{
// Declares the custom control that must be built programmatically.
Table _table;
private String _title;
private int _rows;
private int _columns;
Hashtable _cellObjects = new Hashtable();
// Rows property to be used as the attribute name in the Web page.
public int Rows
{
get
{ return _rows; }
set
{ _rows = value; }
}
// Columns property to be used as the attribute name in the Web page.
public int Columns
{
get
{ return _columns; }
set
{ _columns = value; }
}
// Title property to be used as the attribute name in the Web page.
public string Title
{
get
{ return _title; }
set
{ _title = value; }
}
protected void createNewRow(int rowNumber)
{
// Creates a row and adds it to the table.
TableRow row;
row = new TableRow();
_table.Rows.Add(row);
// Creates a cell that contains text.
for (int y = 0; y < Columns; y++)
appendCell(row, rowNumber, y);
}
protected void appendCell(TableRow row, int rowNumber, int cellNumber)
{
TableCell cell;
TextBox textbox;
cell = new TableCell();
textbox = new TextBox();
cell.Controls.Add(textbox);
textbox.ID = "r" + rowNumber.ToString() + "c" + cellNumber.ToString();
// Checks for the MyCell child object.
if (_cellObjects[textbox.ID] != null)
{
MyCell cellLookup;
cellLookup = (MyCell)_cellObjects[textbox.ID];
textbox.Text = cellLookup.Text;
textbox.BackColor = cellLookup.BackColor;
}
else
textbox.Text = "Row: " + rowNumber.ToString() + " Cell: " +
cellNumber.ToString();
row.Cells.Add(cell);
}
// Called at runtime when a child object is added to the collection.
protected override void AddParsedSubObject(object obj)
{
MyCell cell = obj as MyCell;
if (cell != null)
{
_cellObjects.Add(cell.CellID, cell);
}
}
protected override void OnPreRender(EventArgs e)
/*
* Function name: OnPreRender.
* Carries out changes affecting the control state and renders the resulting UI.
*/
{
// Increases the number of rows if needed.
while (_table.Rows.Count < Rows)
{
createNewRow(_table.Rows.Count);
}
// Checks that each row has the correct number of columns.
for (int i = 0; i < _table.Rows.Count; i++)
{
while (_table.Rows[i].Cells.Count < Columns)
{
appendCell(_table.Rows[i], i, _table.Rows[i].Cells.Count);
}
while (_table.Rows[i].Cells.Count > Columns)
{
_table.Rows[i].Cells.RemoveAt(_table.Rows[i].Cells.Count - 1);
}
}
}
protected override void CreateChildControls()
/*
* Function name: CreateChildControls.
* Adds the Table and the text control to the control collection.
*/
{
LiteralControl text;
// Initializes the text control using the Title property.
text = new LiteralControl("<h5>" + Title + "</h5>");
Controls.Add(text);
_table = new Table();
_table.BorderWidth = 2;
Controls.Add(_table);
}
}
}
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Collections
Imports System.Drawing
Imports System.Security.Permissions
Namespace CustomControls
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Class MyTableCell
Inherits TableCell
Implements INamingContainer
End Class
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Class MyCell
Inherits Control
Implements INamingContainer
' Class Name: MyCell.
' Declares the class for the child controls to be included in the control collection.
Private _id As String
Private _value As String
Private _backColor As Color
Public Property CellID() As String
Get
Return _id
End Get
Set(ByVal value As String)
_id = value
End Set
End Property
Public Property Text() As String
Get
Return _value
End Get
Set(ByVal value As String)
_value = value
End Set
End Property
Public Property BackColor() As Color
Get
Return _backColor
End Get
Set(ByVal value As Color)
_backColor = value
End Set
End Property
End Class
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Class MyControlBuilderVB
Inherits ControlBuilder
Public Overrides Function GetChildControlType(ByVal tagName As String, ByVal attribs As IDictionary) As Type
' Allows TableRow without "runat=server" attribute to be added to the collection.
If (String.Compare(tagName, "mycell", True) = 0) Then
Return GetType(MyCell)
End If
Return Nothing
End Function
' Ignores literals between rows.
Public Overrides Sub AppendLiteralString(ByVal s As String)
' Ignores literals between rows.
End Sub
End Class
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal), ControlBuilderAttribute(GetType(MyControlBuilderVB))> _
Public Class MyVB_CustomControl
Inherits Control
Implements INamingContainer
' Class name: MyVB_CustomControl.
' Processes the element declarations within a control
' declaration. This builds the actual control.
' Custom control to build programmatically.
Private _table As Table
Private _cellObjects As New Hashtable()
' Variables that must contain the control attributes as defined in the Web page.
Private _rows As Integer
Private _columns As Integer
Private _title As String
' Rows property to be used as the attribute name in the Web page.
Public Property Rows() As Integer
Get
Return _rows
End Get
Set(ByVal value As Integer)
_rows = value
End Set
End Property
' Columns property to be used as the attribute name in the Web page.
Public Property Columns() As Integer
Get
Return _columns
End Get
Set(ByVal value As Integer)
_columns = value
End Set
End Property
' Title property to be used as the attribute name in the Web page
Public Property Title() As String
Get
Return _title
End Get
Set(ByVal value As String)
_title = value
End Set
End Property
Protected Sub createNewRow(ByVal rowNumber As Integer)
' Creates a row and adds it to the table.
Dim row As TableRow
row = New TableRow()
_table.Rows.Add(row)
' Creates a cell that contains text.
Dim y As Integer
For y = 0 To Columns - 1
appendCell(row, rowNumber, y)
Next y
End Sub
Protected Sub appendCell(ByVal row As TableRow, ByVal rowNumber As Integer, ByVal cellNumber As Integer)
Dim cell As TableCell
Dim textbox As TextBox
cell = New TableCell()
textbox = New TextBox()
cell.Controls.Add(textbox)
textbox.ID = "r" + rowNumber.ToString() + "c" + cellNumber.ToString()
' Checks for the MyCell child object.
If Not (_cellObjects(textbox.ID) Is Nothing) Then
Dim cellLookup As MyCell
cellLookup = CType(_cellObjects(textbox.ID), MyCell)
textbox.Text = cellLookup.Text
textbox.BackColor = cellLookup.BackColor
Else
textbox.Text = "Row: " + rowNumber.ToString() + " Cell: " + cellNumber.ToString()
End If
row.Cells.Add(cell)
End Sub
' Called at runtime when a child object is added to the collection.
Protected Overrides Sub AddParsedSubObject(ByVal obj As Object)
Dim cell As MyCell = CType(obj, MyCell)
If Not (cell Is Nothing) Then
_cellObjects.Add(cell.CellID, cell)
End If
End Sub
Protected Overrides Sub OnPreRender(ByVal e As EventArgs)
' Sub name: OnPreRender.
' Carries out changes affecting the control state and renders the resulting UI.
' Increases the number of rows if needed.
While _table.Rows.Count < Rows
createNewRow(_table.Rows.Count)
End While
' Checks that each row has the correct number of columns.
Dim i As Integer
For i = 0 To _table.Rows.Count - 1
While _table.Rows(i).Cells.Count < Columns
appendCell(_table.Rows(i), i, _table.Rows(i).Cells.Count)
End While
While _table.Rows(i).Cells.Count > Columns
_table.Rows(i).Cells.RemoveAt((_table.Rows(i).Cells.Count - 1))
End While
Next i
End Sub
<System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
Protected Overrides Sub CreateChildControls()
' Sub name: CreateChildControls.
' Adds the Table and the text controls to the control collection.
Dim [text] As LiteralControl
' Initializes the text control using the Title property.
[text] = New LiteralControl("<h5>" + Title + "</h5>")
Controls.Add([text])
_table = New Table()
Controls.Add(_table)
End Sub
End Class
End Namespace
下面的代码示例使用上一个自定义控件。 具体而言，它会生成一个表，该表的属性和内容在运行时定义。 请注意， @ Register 指令中显示的值反映了上一个命令行。
<%@ Page Language="C#" %>
<%@ Register TagPrefix="AspNetSamples" Assembly="cs_mycontrolbuilder" Namespace="CustomControls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ControlBuilder Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<AspNetSamples:MyCS_CustomControl id="Custom1"
title="Auto-Generated Table"
columns="3"
rows="3"
runat="server">
<mycell cellid="r0c0" BackColor="red" text="red cell"></mycell>
<mycell cellid="r2c2" BackColor="green" text="green cell"></mycell>
</AspNetSamples:MyCS_CustomControl>
</div>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<%@ Register TagPrefix="AspNetSamples" Assembly="vb_mycontrolbuilder" Namespace="CustomControls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ControlBuilder Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<AspNetSamples:MyVB_CustomControl id="Custom1"
title="Auto-Generated Table"
columns="3"
rows="3"
runat="server">
<mycell cellid="r0c0" BackColor="red" text="red cell"></mycell>
<mycell cellid="r2c2" BackColor="green" text="green cell"></mycell>
</AspNetSamples:MyVB_CustomControl>
</div>
</form>
</body>
</html>
注解
默认情况下，页面上的每个控件都与默认 ControlBuilder 类相关联。 在分析期间，ASP.NET 页框架会 ControlBuilder 生成对应于页面控件树的对象树。 然后，该 ControlBuilder 树用于生成页面代码以创建控件树。 除了子控件之外， 还 ControlBuilder 定义如何分析控件标记中的内容的行为。 可以通过定义自己的自定义控件生成器类来替代此默认行为。 这是通过将特性应用于 ControlBuilderAttribute 控件生成器类来完成的，如下所示：
[ControlBuilderAttribute(typeof(ControlBuilderType))]
构造函数
| ControlBuilder() |
初始化 ControlBuilder 类的新实例。 |
字段
| DesignerFilter |
表示 |
