asp.net - Visual STudio 2010 中的 ASP.net。使用下拉列表和提交按钮

Question

我是 Visual Studio 2010 的新手。我有一个下拉列表，可以从基本的 select from 语句中提取数据列表。下拉列表中只有 4 个选项。假设只有苹果、香蕉、梨和葡萄。我如何做到这一点，当我选择苹果时它会重定向到一个页面，但是如果我选择香蕉它会重定向到另一个页面？目前我有提交按钮指向一个页面，但我如何让它根据用户选择动态变化？

Answer 1

处理 select 元素的 onchange 事件：

function getComboA(sel) {
    var value = sel.options[sel.selectedIndex].value;  
    // decide what to do with value for example
    if(value=='apple')
      window.location='pages.aspx';

}

<asp:dropDownList onchange="getComboA(this);" ...

Answer 2

到这个时候你不需要渲染任何控制asp。

选项1

<select id="myselect" onchange="myfunction();">
    <option value=""></option>
    <option value="apple">apple</option>
    <option value="banana">banana</option>
    <option value="pear">pear</option>
    <option value="grapes">grapes</option>
</select>
<script type="text/javascript">
    function myfunction() {
        var value = $("#myselect").val();
        switch (value) {
            case "apple":
                window.location = "http://www.apple.com/";
                break;
            case "banana":
                window.location = "http://www.google.com/";
                break;
            case "pear":
                window.location = "http://www.apple.com/";
                break;
            case "grapes":
                window.location = "http://www.apple.com/";
                break;
        }
    }
</script>

选项 2

<asp:DropDownList ID="myselect" onchange="myfunction();" runat="server">
    <asp:ListItem Text="apple" Value="apple" />
    <asp:ListItem Text="banana" Value="banana" />
    <asp:ListItem Text="pear" Value="pear" />
    <asp:ListItem Text="grapes" Value="grapes" />
</asp:DropDownList>
<script type="text/javascript">
    function myfunction() {
        var value = $("#<%= myselect.ClientID %>").val();
        switch (value) {
            case "apple":
                window.location = "http://www.apple.com/";
                break;
            case "banana":
                window.location = "http://www.google.com/";
                break;
            case "pear":
                window.location = "http://www.apple.com/";
                break;
            case "grapes":
                window.location = "http://www.apple.com/";
                break;
        }
    }
</script>

选项 3（需要回发）

<asp:DropDownList ID="myselect" runat="server" OnSelectedIndexChanged="myselect_SelectedIndexChanged" AutoPostBack="True">
    <asp:ListItem Text="apple" Value="apple" />
    <asp:ListItem Text="banana" Value="banana" />
    <asp:ListItem Text="pear" Value="pear" />
    <asp:ListItem Text="grapes" Value="grapes" />
</asp:DropDownList>

在 .cs 后面的代码中

protected void myselect_SelectedIndexChanged(object sender, EventArgs e)
{
    switch (myselect.SelectedValue)
    {
        case "apple":
            Response.Redirect("http://www.apple.com/");
            break;
        case "banana":
            Response.Redirect("http://www.apple.com/");
            break;
        case "pear":
            Response.Redirect("http://www.apple.com/");
            break;
        case "grapes":
            Response.Redirect("http://www.apple.com/");
            break;
    }
}