c# - 如何确定回发是否由 UserControl 引起

Question

我在哪个控制导致回发的帖子中尝试了这个建议，但它在我的情况下不起作用。控件名称以 UserControl 名称为前缀。有没有办法获取对 UserControl 上动态添加的控件的引用？

Answer 1

尝试这个：

if (IsPostBack)
{ 
  var targetID = Request.Form["__EVENTTARGET"];
  if (!String.IsNulOrEmpty(targetID)
  {
      var targetControl = this.Page.FindControl(targetID);
  }
}

Answer 2

您可以让您的用户控件公开事件。您背后的 aspx 页面代码应该有一个在此类事件上调用的方法。

public delegate void EventFiredHandler(object sender);

public class MyUserControl: UserControl
{
    public event EventFiredHandler EventFired;

    //Let all your button clicks in usercontrol share this event sink
    void Button1_Click(object sender, EventArgs e)
    {
        if(EventFired != null)
        {
            EventFired(sender);
        }
    }
}

在您的 aspx 标记中，您可以编写如下内容：

<uc1:MyUserControl runat="server" 
    EventFired="UCControl_EventFired"></uc1:MyUserControl>

在后面的aspx代码中：

protected void UCControl_EventFired(object sender)
{
    //Obtaining reference of control in usercontrol 
    // which caused event
    Button btn = (Button) sender;
}

Answer 3

到目前为止发布的答案都不是正确的。这个是。我在页面加载事件中使用这些函数来检查按钮单击等，并且根本不使用控制事件，因为它们发生得太晚了，我的口味，你必须绑定数据两次。

    // Returns true if postback is from current control or one of child controls of current control.
    // Returns false if postback is from any other controls (siblings or parents of the siblings) or if there is no postback.
    public bool IsPostBackFromCurrentControl()
    {
        return IsPostBackFromControlOrItsChildren(this);
    }

    // Returns true if postback is from the control or one of child controls of the control.
    // Returns false if postback is from any other controls (siblings, parents of the siblings or parent of current control) or if there is no postback.
    public bool IsPostBackFromControlOrItsChildren(Control ctl)
    {
        if (IsPostBack)
        {
            string eventTarget = Request["__EVENTTARGET"];
            if (eventTarget.StartsWith(ctl.UniqueID) || eventTarget.StartsWith(ctl.ClientID))
                return true;
            else
                return false;
        }
        return false;
    }

    // Returns true if postback is from the control.
    // Returns false if postback is from any other controls (siblings, parents of the siblings or parent or child of current control) or if there is no postback.
    public bool IsPostBackFromControl(Control ctl)
    {
        if (IsPostBack)
        {
            string eventTarget = Request["__EVENTTARGET"];
            if (eventTarget == ctl.UniqueID || eventTarget == ctl.ClientID)
                return true;
            else
                return false;
        }
        return false;
    }

使用这个辅助函数，查看如何读取原始回发数据：

    public void ShowAllPostBackData()
    {
        if (IsPostBack)
        {
            string[] keys = Request.Form.AllKeys;
            Literal ctlAllPostbackData = new Literal();
            ctlAllPostbackData.Text = "<div class='well well-lg' style='border:1px solid black;z-index:99999;position:absolute;'><h3>All postback data:</h3><br />";
            for (int i = 0; i < keys.Length; i++)
            {
                ctlAllPostbackData.Text += "<b>" + keys[i] + "</b>: " + Request[keys[i]] + "<br />";
            }
            ctlAllPostbackData.Text += "</div>";
            this.Controls.Add(ctlAllPostbackData);
        }
    }