在ASP中找到控制：按钮单击事件中继器 [英] Find Control in asp:repeater on button click event

问题描述

我有一个ASP内部下拉列表：repeater项目模板。
我怎样才能得到它的按钮单击事件的价值。

I have a dropdown list inside a asp:repeater item template. how can I get its value on button click event.

<asp:Repeater runat="server" ID="WorkflowListAfter" onitemcreated="WorkflowListAfterItemCreated">
    <ItemTemplate>
         <asp:DropDownList ID="ddlWorkflowMembers" runat="server" DataTextField="MemberName" DataValueField="MemberID">
    </ItemTemplate>
</asp:Repeater>

protected DropDownList ddlWorkflowMembers = new DropDownList();
protected void WorkflowListAfterItemCreated(object sender, RepeaterItemEventArgs e)
{
    ddlWorkflowMembers = (DropDownList) e.Item.FindControl("ddlWorkflowMembers");
}
protected void BtnSaveClick(object sender, EventArgs e) {
    if (ddlWorkflowMembers.SelectedItem == null) return;
}

在code以上的工作，在第一时间，但回发ddlWorkflowMembers后总是空expersion。

the code above is working at first time but after postback ddlWorkflowMembers is always null expersion.

推荐答案

假设 BtnSave 也是中继器内。

您获得的RepeaterItem 通过转换按钮的<一个href=\"http://msdn.microsoft.com/en-us/library/system.web.ui.control.namingcontainer.aspx\"><$c$c>NamingContainer.然后你可以使用的FindControl 来获得关于你的DropDownList ：

You get the RepeaterItem by casting the button's NamingContainer. Then you can use FindControl to get the reference to your DropDownList:

protected void BtnSaveClick(object sender, EventArgs e) {
    var btn =  (Button)sender;
    var item = (RepeaterItem)btn.NamingContainer;
    var ddl =  (DropDownList) item.FindControl("ddlWorkflowMembers");
    // ...
}

如果该按钮是中继器之外，并要保存所有的项目，你完成所有需要循环：

If the button is outside of the repeater and you want to save all items, you need to loop through all:

protected void BtnSaveClick(object sender, EventArgs e) {
    foreach(RepeaterItem item in WorkflowListAfter.Items)
    {
        var ddl =  (DropDownList) item.FindControl("ddlWorkflowMembers");
        // ...
    }       
}

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