C# ASP.NET 动态添加 UserControl 到 PlaceHolder，不触发 Click 事件，只触发 Page_Load
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ASP.NET dynamically adding UserControl to PlaceHolder, not fire Click Event, only Page_Load
提问by Pepa Zapletal
In my ASP.Net page I have PlaceHolder and Button. When user click on this button, I add some UserControls from my Interface method getControl to the PlaceHolder. Code:
在我的 ASP.Net 页面中，我有 PlaceHolder 和 Button。当用户单击此按钮时，我将一些 UserControl 从我的接口方法 getControl 添加到 PlaceHolder。代码：
protected void ActionBtn_Click(object sender, EventArgs e)
{
if (provider != null)
{
actualObject = (PlaceHolder)provider.getControl();
PlaceHolder1.Controls.Add(actualObject);
}
}
Method getControl:
方法getControl：
public object getControl()
{
ph = new PlaceHolder();
exportInbBtn = new Button();
exportInbBtn.Text = "Export Inventury";
exportInbBtn.Click += new EventHandler(myButton_ServerClick);
ph.Controls.Add(exportInbBtn);
exportInbBtn.ID = "exportInbBtn";
return ph;
}
Methods Page_Load and Page_Init in ASP page are empty. Problem is, when the user click at the button exportInbBtn (with text: "Export Inventury"), the click event myButton_ServerClick will not rise. Only web page refresh. I ready some answers, but I can′t figure how easily solve this problem.
ASP页面中的Page_Load和Page_Init方法为空。问题是，当用户单击按钮 exportInbBtn（带有文本：“Export Inventury”）时，单击事件 myButton_ServerClick 不会上升。只刷新网页。我准备了一些答案，但我无法想象解决这个问题有多容易。
采纳答案by Rudis
If you fire *myButton_ServerClick* event, postback is invoked and ASP.Net want to fire called event, but your control is not added to the page, that's why ASP.Net ignore this event.
如果你触发 *myButton_ServerClick* 事件，回发被调用并且 ASP.Net 想要触发被调用的事件，但是你的控件没有添加到页面，这就是 ASP.Net 忽略这个事件的原因。
After postback and before event to be fired, you must add your control again and after them, event will be invoked.
在回发之后和触发事件之前，您必须再次添加您的控件，在它们之后，将调用事件。
Update
更新
Something like this
像这样的东西
Page:
页：
<asp:Button runat="server" ID="btnTest" Text="Add control" OnClick="btnTest_Click"/>
<asp:Label runat="server" ID="result"></asp:Label>
<asp:HiddenField runat="server" ID="controlLoaded"/>
<asp:PlaceHolder runat="server" ID="phTest"></asp:PlaceHolder>
Code behind:
后面的代码：
protected void Page_Load(object sender, EventArgs e)
{
if (controlLoaded.Value == "1")
{
AddControl();
}
}
protected void btnTest_Click(object sender, EventArgs e)
{
AddControl();
}
protected void myButton_ServerClick(object sender, EventArgs e)
{
result.Text = "OK";
}
public object getControl()
{
var ph = new PlaceHolder();
var exportInbBtn = new Button();
exportInbBtn.Text = "Export Inventury";
exportInbBtn.Click += new EventHandler(myButton_ServerClick);
ph.Controls.Add(exportInbBtn);
exportInbBtn.ID = "exportInbBtn";
return ph;
}
private void AddControl()
{
var actualObject = (PlaceHolder)getControl();
phTest.Controls.Add(actualObject);
controlLoaded.Value = "1";
}
回答by KhaledDev
page.aspx
页面.aspx
<asp:PlaceHolder ID="PlaceHolder1" runat="server" ></asp:PlaceHolder>
page.aspx.vb
页面.aspx.vb
Private Sub CreateControl()
Dim vw As Control
vw = CType(LoadControl("~/View01.ascx"), View01)
vw.ID = "View_Dyn"
PlaceHolder1.Controls.Clear()
PlaceHolder1.Controls.Add(vw)
End Sub
Recreate it every postback
每次回发重新创建它
Private Sub Page_Init(sender As Object, e As System.EventArgs) Handles Me.Init
CreateControl()
End Sub
回答by Naresh Mittal
Please note that UserControls are added by the below method - // First create the instance of user control var control = Page.LoadControl("~/folder1/UserControl1.ascx")
请注意，UserControls 是通过以下方法添加的 - // 首先创建用户控件的实例 var control = Page.LoadControl("~/folder1/UserControl1.ascx")
// Now add this control to placeholder as - placeHolder1.Controls.Add(control);
// 现在将此控件添加到占位符作为 - placeHolder1.Controls.Add(control);
I hope this helps.
我希望这有帮助。
