ASP.Net c#-如何从App#U代码类中实例化WebUserControl的实例？

阿罗哈

我有一个自定义控件，需要从类中实例化并添加到页面中。我的类有一个函数，我将

页面传递给它，这样我就可以访问页面上的控件。我正在使用这个方法来添加标准的ASP控件，所有的东西都可以正常工作。我的问题是自定义控件的类型是否已定义

我阅读了将.cs从控件移动到App_Code文件夹中的步骤，但当我这样做时，它将不会编译，因为它不认为ascx中的控件有效。例如，我得到
CS0103:名称“litest”在当前上下文中不存在
。因为它们是分部类，所以我在App_Code文件夹中创建了一个新的空分部类，并保留了控件的.cs文件

它是这样编译的，但是当我将控件添加到Page.controls集合时，我在页面上看不到它应该在哪里。例如，我在ascx文件的底部添加了
TEST
，但我在页面上看不到它。此外，该控件还有一些我需要设置的变量，在使用空的分部类时，我无权访问这些变量

我知道我试图用标准控件做的工作，为什么我不能用自定义控件来做呢

应用程序代码文件夹中的我的部分类：

public partial class CustomControlClass : System.Web.UI.UserControl
{

}

public partial class CustomControlClass : System.Web.UI.UserControl
{
    private int _myValue= -1;
    public int myValue
    {
        get { return _myValue; }
        set { _myValue= value; }
    }
    protected void Page_Init(object sender, EventArgs e)
    {
        litTest.Text = "TEST";
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="CustomControlClass.ascx.cs" Inherits="CustomControlClass" %>
<asp:Literal ID="litTest" runat="server"></asp:Literal>
TEST

public class MyClass
{
    public static void doWork(Page Ctrl)
    {
        CustomControlClass c = new CustomControlClass();
        //c.myValue = 1;  // Wont compile with this line
        Ctrl.Controls.Add(c);

        Literal l = new Literal();
        l.Text = "HELLO";
        Ctrl.Controls.Add(l);
    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for BaseMyControls
/// </summary>
public class BaseMyControls  : System.Web.UI.UserControl
{
    public string strProperty;

    public BaseMyControls()
    {

    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for SomeClassInApp_Code
/// </summary>
public class SomeClassInApp_Code
{
    public static System.Web.UI.Control GetNewUserControl(string someString)
    {
        BaseMyControls bc = (BaseMyControls)(new System.Web.UI.UserControl()).LoadControl("~/controls/MyUC.ascx");
        bc.strProperty = someString;
        return bc;
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="MyUC.ascx.cs" Inherits="MyUC" %>
<asp:Label runat="server" ID="lbl" /></asp:Label>

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class MyUC : BaseMyControls
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string a = this.strProperty;

        lbl.Text = a;
    }
}

用户控件中的我的部分类：

public partial class CustomControlClass : System.Web.UI.UserControl
{

}

public partial class CustomControlClass : System.Web.UI.UserControl
{
    private int _myValue= -1;
    public int myValue
    {
        get { return _myValue; }
        set { _myValue= value; }
    }
    protected void Page_Init(object sender, EventArgs e)
    {
        litTest.Text = "TEST";
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="CustomControlClass.ascx.cs" Inherits="CustomControlClass" %>
<asp:Literal ID="litTest" runat="server"></asp:Literal>
TEST

public class MyClass
{
    public static void doWork(Page Ctrl)
    {
        CustomControlClass c = new CustomControlClass();
        //c.myValue = 1;  // Wont compile with this line
        Ctrl.Controls.Add(c);

        Literal l = new Literal();
        l.Text = "HELLO";
        Ctrl.Controls.Add(l);
    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for BaseMyControls
/// </summary>
public class BaseMyControls  : System.Web.UI.UserControl
{
    public string strProperty;

    public BaseMyControls()
    {

    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for SomeClassInApp_Code
/// </summary>
public class SomeClassInApp_Code
{
    public static System.Web.UI.Control GetNewUserControl(string someString)
    {
        BaseMyControls bc = (BaseMyControls)(new System.Web.UI.UserControl()).LoadControl("~/controls/MyUC.ascx");
        bc.strProperty = someString;
        return bc;
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="MyUC.ascx.cs" Inherits="MyUC" %>
<asp:Label runat="server" ID="lbl" /></asp:Label>

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class MyUC : BaseMyControls
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string a = this.strProperty;

        lbl.Text = a;
    }
}

我的用户控件ascx:

public partial class CustomControlClass : System.Web.UI.UserControl
{

}

public partial class CustomControlClass : System.Web.UI.UserControl
{
    private int _myValue= -1;
    public int myValue
    {
        get { return _myValue; }
        set { _myValue= value; }
    }
    protected void Page_Init(object sender, EventArgs e)
    {
        litTest.Text = "TEST";
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="CustomControlClass.ascx.cs" Inherits="CustomControlClass" %>
<asp:Literal ID="litTest" runat="server"></asp:Literal>
TEST

public class MyClass
{
    public static void doWork(Page Ctrl)
    {
        CustomControlClass c = new CustomControlClass();
        //c.myValue = 1;  // Wont compile with this line
        Ctrl.Controls.Add(c);

        Literal l = new Literal();
        l.Text = "HELLO";
        Ctrl.Controls.Add(l);
    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for BaseMyControls
/// </summary>
public class BaseMyControls  : System.Web.UI.UserControl
{
    public string strProperty;

    public BaseMyControls()
    {

    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for SomeClassInApp_Code
/// </summary>
public class SomeClassInApp_Code
{
    public static System.Web.UI.Control GetNewUserControl(string someString)
    {
        BaseMyControls bc = (BaseMyControls)(new System.Web.UI.UserControl()).LoadControl("~/controls/MyUC.ascx");
        bc.strProperty = someString;
        return bc;
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="MyUC.ascx.cs" Inherits="MyUC" %>
<asp:Label runat="server" ID="lbl" /></asp:Label>

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class MyUC : BaseMyControls
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string a = this.strProperty;

        lbl.Text = a;
    }
}

页面输出上根本没有单词TEST。“你好”这个词显示得很好。我尝试从页面
Load
，
Init
和
PreInit
回调调用
MyClass.doWork（）
，所有这些都会导致dame事件

更新：

public partial class CustomControlClass : System.Web.UI.UserControl
{

}

public partial class CustomControlClass : System.Web.UI.UserControl
{
    private int _myValue= -1;
    public int myValue
    {
        get { return _myValue; }
        set { _myValue= value; }
    }
    protected void Page_Init(object sender, EventArgs e)
    {
        litTest.Text = "TEST";
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="CustomControlClass.ascx.cs" Inherits="CustomControlClass" %>
<asp:Literal ID="litTest" runat="server"></asp:Literal>
TEST

public class MyClass
{
    public static void doWork(Page Ctrl)
    {
        CustomControlClass c = new CustomControlClass();
        //c.myValue = 1;  // Wont compile with this line
        Ctrl.Controls.Add(c);

        Literal l = new Literal();
        l.Text = "HELLO";
        Ctrl.Controls.Add(l);
    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for BaseMyControls
/// </summary>
public class BaseMyControls  : System.Web.UI.UserControl
{
    public string strProperty;

    public BaseMyControls()
    {

    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for SomeClassInApp_Code
/// </summary>
public class SomeClassInApp_Code
{
    public static System.Web.UI.Control GetNewUserControl(string someString)
    {
        BaseMyControls bc = (BaseMyControls)(new System.Web.UI.UserControl()).LoadControl("~/controls/MyUC.ascx");
        bc.strProperty = someString;
        return bc;
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="MyUC.ascx.cs" Inherits="MyUC" %>
<asp:Label runat="server" ID="lbl" /></asp:Label>

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class MyUC : BaseMyControls
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string a = this.strProperty;

        lbl.Text = a;
    }
}

正如Minh Nguyen建议的那样，我可以使用
Ctrl.LoadControl（“~/Controls/CustomControlClass.ascx”）
要加载控件，但我无法将其强制转换为自己的类型，我必须将其指定为控件类型：

Control c= Ctrl.LoadControl("~/Controls/CustomControlClass.ascx");

这样做可以将控件添加到页面中，并使其按预期工作。缺点是我无法访问任何控件属性。为了解决这个问题，我正在这样做：

c.GetType().GetProperty("myValue").SetValue(c, 1, null);

这是可行的，但我不确定使用起来有多贵。我希望我可以直接转换控件，但是我尝试时出错了

我暂时不回答这个问题，看看是否还有其他选择。
使用

CustomControlClass c = (CustomControlClass)Ctrl.LoadControl("~/VirtualPathToASCX/CustomControlClass.ascx");

而不是

CustomControlClass c = new CustomControlClass();

更新：修复演员阵容错误

//LoadControl
ASP.customcontrolclass_ascx c = (ASP.customcontrolclass_ascx)this.LoadControl("~/Controls/CustomControlClass.ascx");
//set myValue
c.myValue = 3;

您无法在VS AutoComplete列表中看到ASP.customcontrolclass\u ascx类型，但它编译时没有错误。
不确定您的代码发生了什么，但主要使用您显示的内容对我有效：

~/controls/testControl.ascx：

<%@ Control Language='C#' AutoEventWireup='false' 
  Inherits='CustomControlClass' 
%>
<asp:Literal ID='litTest' runat='server'></asp:Literal>

<%@ Page Language='C#' %>
<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Transitional//EN' 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'>
<script runat='server'>
protected override void OnInit(EventArgs e) {
  base.OnInit(e);
  MyClass.doWork(this.Page);
}
</script>
<html xmlns='http://www.w3.org/1999/xhtml'>
<head runat='server'><title></title></head>
<body><form id='form1' runat='server'>
</form></body></html>

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

public partial class CustomControlClass : System.Web.UI.UserControl {
  private int _myValue= -1;
  public int myValue {
    get { return _myValue; }
    set { _myValue= value; }
  }
  private Literal _litTest;
  public Literal litTest {
    get { return _litTest; }
    set { _litTest= value; }

  }
  protected override void  OnInit(EventArgs e) {
    base.OnInit(e);
    litTest.Text = "TEST";
  }
}

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

public class MyClass {
  public static void doWork(Page Ctrl) {
    CustomControlClass c = 
      (CustomControlClass) Ctrl.LoadControl("~/controls/testControl.ascx");
    c.myValue = 1;
    Ctrl.Form.Controls.Add(c);

    Literal l = new Literal();
    l.Text = string.Format(
      "<p>CustomControlClass.myValue: {0} </p>", 
      c.myValue
    )
    + string.Format(
      "<p>CustomControlClass.litTest.Text: {0} </p>", 
      c.litTest.Text
    )
    ;
    Ctrl.Form.Controls.Add(l);
  }
}

~/app\u code/MyClass：

<%@ Control Language='C#' AutoEventWireup='false' 
  Inherits='CustomControlClass' 
%>
<asp:Literal ID='litTest' runat='server'></asp:Literal>

<%@ Page Language='C#' %>
<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Transitional//EN' 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'>
<script runat='server'>
protected override void OnInit(EventArgs e) {
  base.OnInit(e);
  MyClass.doWork(this.Page);
}
</script>
<html xmlns='http://www.w3.org/1999/xhtml'>
<head runat='server'><title></title></head>
<body><form id='form1' runat='server'>
</form></body></html>

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

public partial class CustomControlClass : System.Web.UI.UserControl {
  private int _myValue= -1;
  public int myValue {
    get { return _myValue; }
    set { _myValue= value; }
  }
  private Literal _litTest;
  public Literal litTest {
    get { return _litTest; }
    set { _litTest= value; }

  }
  protected override void  OnInit(EventArgs e) {
    base.OnInit(e);
    litTest.Text = "TEST";
  }
}

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

public class MyClass {
  public static void doWork(Page Ctrl) {
    CustomControlClass c = 
      (CustomControlClass) Ctrl.LoadControl("~/controls/testControl.ascx");
    c.myValue = 1;
    Ctrl.Form.Controls.Add(c);

    Literal l = new Literal();
    l.Text = string.Format(
      "<p>CustomControlClass.myValue: {0} </p>", 
      c.myValue
    )
    + string.Format(
      "<p>CustomControlClass.litTest.Text: {0} </p>", 
      c.litTest.Text
    )
    ;
    Ctrl.Form.Controls.Add(l);
  }
}

使用系统；
使用System.Web；
使用System.Web.UI；
使用System.Web.UI.WebControl；
公共类MyClass{
公共静态无效工作（页面Ctrl）{
CustomControlClass c=
（CustomControlClass）Ctrl.LoadControl（“~/controls/testControl.ascx”）；
c、 myValue=1；
Ctrl.Form.Controls.Add（c）；
文字l=新文字（）；
l、 Text=string.Format(
“CustomControlClass.myValue:{0}
”，
c、 我的价值
)
+字符串格式(
“CustomControlClass.litTest.Text:{0}
”，
c、 小文本
)
;
Ctrl.Form.Controls.Add（l）；
}
}

换句话说，调用LoadControl（）时转换到CustomControlClass对我很有效。如果我理解正确，这就是问题所在？
另一种有效的负载控制方式（仅测试了.NET 4）

在您可以调用的任何页面中，用法如下

protected void Page_Load(object sender, EventArgs e)
{
    Control ctrl = SomeClass.GetNewUserControl( "hello add me");

    Panel1.Controls.Add(ctrl);
}

~/app\u code/BaseMyControls.cs:

public partial class CustomControlClass : System.Web.UI.UserControl
{

}

public partial class CustomControlClass : System.Web.UI.UserControl
{
    private int _myValue= -1;
    public int myValue
    {
        get { return _myValue; }
        set { _myValue= value; }
    }
    protected void Page_Init(object sender, EventArgs e)
    {
        litTest.Text = "TEST";
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="CustomControlClass.ascx.cs" Inherits="CustomControlClass" %>
<asp:Literal ID="litTest" runat="server"></asp:Literal>
TEST

public class MyClass
{
    public static void doWork(Page Ctrl)
    {
        CustomControlClass c = new CustomControlClass();
        //c.myValue = 1;  // Wont compile with this line
        Ctrl.Controls.Add(c);

        Literal l = new Literal();
        l.Text = "HELLO";
        Ctrl.Controls.Add(l);
    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for BaseMyControls
/// </summary>
public class BaseMyControls  : System.Web.UI.UserControl
{
    public string strProperty;

    public BaseMyControls()
    {

    }
}

using System;
using System.Collections.Generic;
using System.Web;

/// <summary>
/// Summary description for SomeClassInApp_Code
/// </summary>
public class SomeClassInApp_Code
{
    public static System.Web.UI.Control GetNewUserControl(string someString)
    {
        BaseMyControls bc = (BaseMyControls)(new System.Web.UI.UserControl()).LoadControl("~/controls/MyUC.ascx");
        bc.strProperty = someString;
        return bc;
    }
}

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="MyUC.ascx.cs" Inherits="MyUC" %>
<asp:Label runat="server" ID="lbl" /></asp:Label>

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class MyUC : BaseMyControls
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string a = this.strProperty;

        lbl.Text = a;
    }
}

这更近了！我得到“无法将类型为“ASP.customcontrolclass\u ascx”的对象强制转换为类型为“customcontrolclass”。“如果我使用Control作为类型，它将添加到页面中，并且我看到单词TEST，但我无法设置myValue。当我尝试使用ASP.customcontrolclass\u ascx时，我得到”CS0246：找不到类型或命名空间名称“ASP”（您是否缺少using指令或程序集引用？）“不确定需要添加什么引用才能使ASP命名空间正常工作。与您一样，我也收到了此消息。但忽略它，我尝试构建网站，并已成功编译。（我将VS2008与.Net FrameWork 3.5 sp1一起使用）您的页面是否正确地放置在default.aspx页面上？是的，转换对我不起作用。我得到“无法将类型为'ASP.customcontrolclass_ascx'的对象转换为类型为'customcontrolclass'尝试时出错。我目前已通过反射解决了此问题，但完成工作似乎有些过火。我在发布之前测试了上面的代码。它可以正常工作，包括演员阵容。您愿意尝试吗？