为什么 SelectedIndexChanged 事件不会从 GridView 的下拉列表中触发? [英] Why isn't the SelectedIndexChanged event firing from a dropdownlist in a GridView?

问题描述

我无法触发下拉列表的 SelectedIndexChanged.我有以下几点:

<div><asp:GridView id="grdPoll" runat="server" AutoGenerateColumns="false"><列><asp:TemplateField><项目模板><asp:DropDownList ID="DropDownList1" runat="服务器"自动回传=真"OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"><asp:ListItem Text="Review" Value="Review" Selected="True">Review</asp:ListItem><asp:ListItem Text="Level1" Value="lvl1">发送回 Level1</asp:ListItem></asp:DropDownList></ItemTemplate></asp:TemplateField></列></asp:GridView><asp:Label ID="lblCity" runat="server" Text="Label"></asp:Label>

</表单>

在我后面的代码中，我有这个:

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e){this.lblCity.Text = ((DropDownList)sender).SelectedValue;}

如果我将这个相同的 ddl 放在 gridview 之外，它就会触发.

正在发生回发并且自动回发设置为 true.该事件永远不会触发.为什么我无法从 gridview 中触发我的事件?

谢谢.

解决方案

嗯，这个问题是一个多月前问的，现在可能已经无关紧要了，但是@LFSR 最近好心编辑了它，它在Active问题"列表.

由于它仍未得到答复(224 次观看！)，我想我应该试一试:

<小时>

问题是在 GridView 的上下文中，DropDownList(以下简称 DDL)是一个动态控件，因此它的事件需要在回发时重新附加.

理解了这个概念后，解决方案就变得相对简单了:

ASPX:

<asp:ListItem Text="Review" Value="Review" Selected="True">Review</asp:ListItem><asp:ListItem Text="Level1" Value="lvl1">发送回 Level1</asp:ListItem></asp:DropDownList>

CS 代码:

protected void Page_Load(object sender, EventArgs e){如果(！Page.IsPostBack){//将 GridView 绑定到某物.数据绑定网格();}}protected void DDL1_SelectedIndexChanged(object sender, EventArgs e){this.lblCity.Text = ((DropDownList)sender).SelectedValue;}protected void grdPoll_RowDataBound(object sender, GridViewRowEventArgs e){如果(页面.IsPostBack){if(e.Row.RowType == DataControlRowType.DataRow){DropDownList ddl = e.Row.FindControl("DDL1") as DropDownList;如果(ddl ！= 空){ddl.SelectedIndexChanged += new EventHandler(DDL1_SelectedIndexChanged);}}}}

I cannot get my SelectedIndexChanged of my dropdownlist to fire. I have the following:

<form id="form1" runat="server">
<div>
<asp:GridView id="grdPoll" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:DropDownList ID="DropDownList1" runat="server" 
                 AutoPostBack="true"
                 OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
                    <asp:ListItem Text="Review" Value="Review" Selected="True">Review</asp:ListItem>
                    <asp:ListItem Text="Level1" Value="lvl1">Send Back to Level1</asp:ListItem>
                </asp:DropDownList>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

<asp:Label ID="lblCity" runat="server" Text="Label"></asp:Label>  
</div>
</form>

In my code behind I have this:

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    this.lblCity.Text = ((DropDownList)sender).SelectedValue;
}

If I put this same ddl outside of the gridview, it fires.

The postback is occurring and the autopostback is set to true. The event just never fires. Why can't I get my event to fire from within the gridview?

Thank you.

解决方案

Well, this question was asked more than a month ago and may be irrelevant now, but @LFSR was kind enough to edit it recently, it's in the "Active questions" list.

Since it remains unanswered (224 views!), I thought I should give it a go:

---

The problem is that in the context of a GridView, the DropDownList(referred to hereafter as DDL) is a dynamic control and therefore its events need to be reattached upon Postback.

When this concept is understood, the solution becomes relatively simple :

ASPX:

<asp:DropDownList ID="DDL1" runat="server" AutoPostBack="true" OnSelectedIndexChanged="DDL1_SelectedIndexChanged">
  <asp:ListItem Text="Review" Value="Review" Selected="True">Review</asp:ListItem>
  <asp:ListItem Text="Level1" Value="lvl1">Send Back to Level1</asp:ListItem>
</asp:DropDownList>

CS Code:

protected void Page_Load(object sender, EventArgs e)
{
  if(!Page.IsPostBack)
  {
    // Bind the GridView to something.
    DataBindGrid();
  }
}

protected void DDL1_SelectedIndexChanged(object sender, EventArgs e)
{
  this.lblCity.Text = ((DropDownList)sender).SelectedValue;
}

protected void grdPoll_RowDataBound(object sender, GridViewRowEventArgs e)
{
  if(Page.IsPostBack)
  {
    if(e.Row.RowType == DataControlRowType.DataRow)
    {
      DropDownList ddl = e.Row.FindControl("DDL1") as DropDownList;
      if(ddl != null)
      {
        ddl.SelectedIndexChanged += new EventHandler(DDL1_SelectedIndexChanged);
      }
    }
  }
}

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