Question

我有下拉列表它的事件（不显示你好）不起作用....

aspx页面

<asp:DropDownList ID="DropDownList1" runat="server" 
    onselectedindexchanged="DropDownList1_SelectedIndexChanged">
    <asp:ListItem>1</asp:ListItem>
    <asp:ListItem>2</asp:ListItem>
    <asp:ListItem>3</asp:ListItem>
    <asp:ListItem>4</asp:ListItem>
    <asp:ListItem>5</asp:ListItem>
</asp:DropDownList>

aspx.cs页面

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    Console.WriteLine("Hello");
}

问题是如果我在console.writeline中保持断点它不起作用......我在哪里犯了错误...任何想法。谢谢......

Answer 1

在您的aspx代码中添加AutoPostBack="true"，如下所示：

<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true"
    onselectedindexchanged="DropDownList1_SelectedIndexChanged">
    <asp:ListItem>1</asp:ListItem>
    <asp:ListItem>2</asp:ListItem>
    <asp:ListItem>3</asp:ListItem>
    <asp:ListItem>4</asp:ListItem>
    <asp:ListItem>5</asp:ListItem>
</asp:DropDownList>

Answer 2

//添加AutoPostBack。

  <asp:DropDownList ID="DropDownList1" runat="server" 
        onselectedindexchanged="DropDownList1_SelectedIndexChanged" AutoPostBack="true" >

Answer 3

除了一件事，一切都是正确的。只有在此状态为真时才会触发该事件

设置

AutoPostBack = "true"

//Actual code
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true"
onselectedindexchanged="DropDownList1_SelectedIndexChanged">

为什么下拉事件不起作用asp

3 个答案: