![](/img/trans.png)
[英]Asp.NET custom server control event handler not firing on second postback
[英]ASP.Net Custom Server Control Not Firing Custom Event
我创建了一个自定义服务器控件。 它看起来很棒,并且呈现的HTML也应该如此。 最初,我扩展了ControlContainer,现在扩展了WebControl(两者的行为相同。)它具有两个属性,ImageUrl和Text。 本质上,它将呈现一个带有和标记的通用HTML标记。
我的问题是公开的ServerClick事件(由我相信的NamingContainer)似乎没有触发。 如果我添加任何ASP按钮(“链接”,“图像”或常规按钮)并关联到该Click事件,则将触发它,但是当然,我还有其他呈现的内容。 它可以成功运行javascript并执行__dopostback调用。 但是它不能看到给定的控件ID或其他内容,因为事件永远不会触发。
using System;
using System.ComponentModel;
using System.Drawing.Design;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
namespace PLSO.Info.Web.UI {
[DefaultEvent("Submit")]
[DefaultProperty("Text")]
[ToolboxData("<{0}:ComboButton runat=\"server\"> </{0}:ComboButton>")]
public class ComboButton : WebControl {
private HtmlImage imageControl;
private HtmlGenericControl spanControl;
private static readonly object EventSubmitKey = new object();
[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Description("The text to display on the button.")]
public string Text {
get { return ViewState["NewText"] as string; }
set { ViewState["NewText"] = value; }
}
[DefaultValue("")]
[Bindable(true)]
[Category("Appearance")]
[UrlProperty()]
[Editor("System.Web.UI.Design.ImageUrlEditor, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor))]
public string ImageUrl {
get {
EnsureChildControls();
return this.imageControl.Src;
}
set {
EnsureChildControls();
this.imageControl.Src = value;
}
} // ImageUrl - Property
public override string CssClass {
get { return ViewState["CssClass"] as string; }
set { ViewState["CssClass"] = value; }
}
[Category("Action")]
[Description("Raised when the user clicks the button.")]
public event EventHandler Submit {
add { Events.AddHandler(EventSubmitKey, value); }
remove { Events.RemoveHandler(EventSubmitKey, value); }
}
protected virtual void OnSubmit(EventArgs e) {
EventHandler SubmitHandler = (EventHandler)Events[EventSubmitKey];
if (SubmitHandler != null)
SubmitHandler(this, e);
}
void ComboButton_Submit(object sender, EventArgs e) {
OnSubmit(EventArgs.Empty);
}
protected override void CreateChildControls() {
Controls.Clear();
imageControl = new HtmlImage();
imageControl.Src = this.ImageUrl;
imageControl.Alt = this.Text;
this.Controls.Add(imageControl);
spanControl = new HtmlGenericControl("span");
spanControl.InnerText = this.Text;
this.Controls.Add(spanControl);
this.Submit += new EventHandler(ComboButton_Submit);
ChildControlsCreated = true;
}
protected override void Render(HtmlTextWriter writer) {
PostBackOptions pbo = new PostBackOptions(this);
AddAttributesToRender(writer);
writer.AddAttribute(HtmlTextWriterAttribute.Class, this.CssClass);
writer.AddAttribute("onclick", string.Format("javascript:{0}", Page.ClientScript.GetPostBackEventReference(pbo)));
writer.RenderBeginTag(HtmlTextWriterTag.Button);
imageControl.RenderControl(writer);
spanControl.RenderControl(writer);
writer.RenderEndTag();
}
}
}
这是我的标记。 我放入此控件,然后放入常规的ASP:Button。 该常规按钮的事件被击中! 不是我的。
<ucs:ComboButton ID="btnT4" runat="server" Text="Please" CssClass="PButtonCombo" ImageUrl="~/Styles/icons/edit-find.png" OnSubmit="btnT4_Submit" />
<asp:Button ID="btnT5" runat="server" Text="TEST" onclick="btnT5_Click" UseSubmitBehavior="False" />
这是渲染的HTML:
<button id="MainContent_btnT4" class="PButtonCombo" onclick="javascript:__doPostBack('ctl00$MainContent$btnT4','')"><img src="../Styles/icons/edit-find.png" alt="Please" /><span>Please</span></button>
<input type="button" name="ctl00$MainContent$btnT5" value="TEST" onclick="javascript:__doPostBack('ctl00$MainContent$btnT5','')" id="MainContent_btnT5" />
我必须相信我已经接近了,但是只是想念一些东西。 今天已经调整了几个小时,请帮助!
编辑 :
感谢@James的回答,我所做的就是将以下内容添加到上述示例的顶部。 它成功了,但现在开火了两次。 不知道为什么吗? 这就是我当前的问题:
public class ComboButton : WebControl, IPostBackEventHandler {
public void RaisePostBackEvent(string eventArgument) {
OnClick(new EventArgs());
}
[Category("Action")]
[Description("Raised when the user clicks the button.")]
public event EventHandler Click;
protected virtual void OnClick(EventArgs e) {
if (Click != null)
Click(this, e);
}
编辑2 ==解决方案
using System.ComponentModel;
using System.Drawing.Design;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
namespace PLSO.Info.Web.UI {
[DefaultEvent("Submit")]
[DefaultProperty("Text")]
[ToolboxData("<{0}:ComboButton runat=\"server\"> </{0}:ComboButton>")]
public class ComboButton : Button {
private HtmlImage imageControl;
private HtmlGenericControl spanControl;
[DefaultValue("")]
[Bindable(true)]
[Category("Appearance")]
[UrlProperty()]
[Editor("System.Web.UI.Design.ImageUrlEditor, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor))]
public string ImageUrl {
get {
EnsureChildControls();
return this.imageControl.Src;
}
set {
EnsureChildControls();
this.imageControl.Src = value;
}
} // ImageUrl - Property
protected override void CreateChildControls() {
Controls.Clear();
imageControl = new HtmlImage();
imageControl.Src = this.ImageUrl;
imageControl.Alt = this.Text;
this.Controls.Add(imageControl);
spanControl = new HtmlGenericControl("span");
spanControl.InnerText = this.Text;
this.Controls.Add(spanControl);
ChildControlsCreated = true;
} // CreateChildControls - Method - Override
protected override void Render(HtmlTextWriter writer) {
PostBackOptions pbo = new PostBackOptions(this);
AddAttributesToRender(writer);
writer.RenderBeginTag(HtmlTextWriterTag.Button);
imageControl.RenderControl(writer);
spanControl.RenderControl(writer);
writer.RenderEndTag();
} // Render - Event - Override
}
}
尝试实现IPostBackEventHandler
接口:
public class ComboButton : WebControl, IPostBackEventHandler
{
public void RaisePostBackEvent(string eventArgument)
{
OnSubmit(EventArgs.Empty);
}
}
这是一篇介绍IPostBackEventHandler
接口的实现的文章:
http://msdn.microsoft.com/en-us/library/system.web.ui.ipostbackeventhandler.aspx
编辑
如果事件以某种方式依赖于数据,则需要实现IPostBackDataHandler
接口。 例如,您将使用IPostBackDataHandler
接口来触发TextBox的OnTextChanged
事件:
public class ComboButton : WebControl, IPostBackDataHandler
{
public virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection)
{
return true;
}
public virtual void RaisePostDataChangedEvent()
{
}
}
这是一篇介绍IPostBackDataHandler
接口的实现的文章:
http://msdn.microsoft.com/en-us/library/system.web.ui.ipostbackdatahandler.aspx
您需要研究IPostBackEventHandler
如果未在控件中实现此接口,则ASP.net引擎不会将事件转发到控件。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.