ControlIDConverter 类

定义

public ref class ControlIDConverter : System::ComponentModel::StringConverter

public class ControlIDConverter : System.ComponentModel.StringConverter

type ControlIDConverter = class
    inherit StringConverter

Public Class ControlIDConverter
Inherits StringConverter

继承

Object

TypeConverter

StringConverter

ControlIDConverter

派生

System.Web.UI.WebControls.AssociatedControlConverter

System.Web.UI.WebControls.ValidatedControlConverter

示例

下面的代码示例演示如何在 ControlIDConverter 需要呈现 TypeConverter 控件 ID 的类中使用。 DebugInfoControl这是一个简单的控件，用于输出当前 Web 窗体包含的控件上的一些信息。 其 ControlID 属性用一个 TypeConverterAttribute 指定 ControlIDConverter 用作 TypeConverter 该属性的修饰。 Render重写DebugInfoControl方法以输出有关控件中Label目标控件的信息。

namespace Samples.AspNet.CS {

  using System;
  using System.ComponentModel;
  using System.Web.UI;
  using System.Web.UI.WebControls;

  [DefaultProperty("ControlID")]
  public class DebugInfoControl : Control {

    public DebugInfoControl() {
    }

    public DebugInfoControl(string controlID) {
      ControlID = controlID;
    }

    [DefaultValue(""),
    TypeConverter(typeof(ControlIDConverter))]
    public string ControlID {
      get {
        object o = ViewState["ControlID"];
        if (o == null)
          return String.Empty;
        return (string)o;
      }
      set {
        if (ControlID != value) {
          ViewState["ControlID"] = value;
        }
      }
    }

    protected override void Render(HtmlTextWriter writer) {

      Label info = new Label();

      if (this.ControlID.Length == 0) {
        writer.Write("<Font Color='Red'>No ControlID set.</Font>");
      }

      Control ctrl = this.FindControl(ControlID);

      if (ctrl == null) {
        writer.Write("<Font Color='Red'>Could not find control " +  ControlID + " in Naming Container.</Font>");
      }
      else {
        writer.Write("<Font Color='Green'>Control " + ControlID + " found.<BR>");
        writer.Write("Its Naming Container is: " + ctrl.NamingContainer.ID + "<BR>");
        if (ctrl.EnableViewState)
          writer.Write("It uses view state to persist its state.<BR>");

        if (ctrl.EnableTheming)
          writer.Write("It can be assigned a Theme ID.<BR>");

        if (ctrl.Visible)
          writer.Write("It is visible on the page.<BR>");
        else
          writer.Write("It is not visible on the page.<BR>");

        writer.Write("</Font>");
      }
    }
  }
}

Imports System.ComponentModel
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace Samples.AspNet.VB

  <DefaultProperty("ControlID")>  _
  Public Class DebugInfoControl
     Inherits Control


     Public Sub New()
     End Sub


     Public Sub New(controlID As String)
        ControlID = controlID
     End Sub


     <DefaultValue(""), TypeConverter(GetType(ControlIDConverter))>  _
     Public Property ControlID() As String
        Get
           Dim o As Object = ViewState("ControlID")
           If o Is Nothing Then
              Return String.Empty
           End If
           Return CStr(o)
        End Get
        Set
           If ControlID <> value Then
              ViewState("ControlID") = value
           End If
        End Set
     End Property


     Protected Overrides Sub Render(writer As HtmlTextWriter)

        Dim info As New Label()

        If Me.ControlID.Length = 0 Then
           writer.Write("<Font Color='Red'>No ControlID set.</Font>")
        End If

        Dim ctrl As Control = Me.FindControl(ControlID)


        If ctrl Is Nothing Then
           writer.Write(("<Font Color='Red'>Could not find control " + ControlID + " in Naming Container.</Font>"))
        Else
           writer.Write(("<Font Color='Green'>Control " + ControlID + " found.<BR>"))
           writer.Write(("Its Naming Container is: " + ctrl.NamingContainer.ID + "<BR>"))
           If ctrl.EnableViewState Then
              writer.Write("It uses view state to persist its state.<BR>")
           End If
           If ctrl.EnableTheming Then
              writer.Write("It can be assigned a Theme ID.<BR>")
           End If
           If ctrl.Visible Then
              writer.Write("It is visible on the page.<BR>")
           Else
              writer.Write("It is not visible on the page.<BR>")
           End If
           writer.Write("</Font>")
        End If
     End Sub
  End Class
End Namespace

下面的代码示例演示如何 DebugInfoControl 在 Web 窗体中使用 Web 窗体以及控件 AccessDataSource 来显示有关控件 AccessDataSource 的信息。

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" assembly="Samples.AspNet.CS" %>
<%@Page  Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:accessdatasource
          id="AccessDataSource1"
          runat="server"
          datasourcemode="DataReader"
          datafile="Northwind.mdb"
          selectcommand="SELECT OrderID FROM Orders WHERE EmployeeID=2">
      </asp:accessdatasource>

      <br />
      <aspSample:debuginfocontrol
          id="DebugInfoControl1"
          runat="server"
          controlid="AccessDataSource1" />

    </form>
  </body>
</html>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" assembly="Samples.AspNet.VB" %>
<%@ Page  Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:accessdatasource
          id="AccessDataSource1"
          runat="server"
          datasourcemode="DataReader"
          datafile="Northwind.mdb"
          selectcommand="SELECT OrderID FROM Orders WHERE EmployeeID=2">
      </asp:accessdatasource>

      <br />
      <aspSample:debuginfocontrol
          id="DebugInfoControl1"
          runat="server"
          controlid="AccessDataSource1" />

    </form>
  </body>
</html>

注解

该 ControlIDConverter 类派生自 StringConverter 该类，并提供控件 ID 列表，用于在设计时环境中的属性网格控件中显示。 该ControlIDConverter类还充当类的基类AssociatedControlConverterValidatedControlConverter，这些类是分别支持验证属性属性的 Web 控件和控件的类型转换器。

有关类型转换器的详细信息，请参阅 如何：实现类型转换器 或 通用类型转换。

另请参阅

• TypeConverter
• AssociatedControlConverter
• ValidatedControlConverter
• 如何：实现类型转换器
• 通用类型转换