如何更新下拉列表中更改的选定索引上的标签 [英] how can i update a label on selected index changed in dropdown

问题描述

<asp:DropDownList ID="DropDownList1" runat="server" 

                onselectedindexchanged="DropDownList1_SelectedIndexChanged">
                <asp:ListItem>1
                <asp:ListItem>2
                <asp:ListItem>3
                <asp:ListItem>4
                <asp:ListItem>5
                <asp:ListItem>6

这是一个下拉菜单

this is a dropdown

<asp:Label ID="Label2" runat="server" Text="Label">

这是一个标签



现在我想要更新选择下拉列表或更改下拉列表中的标签，更新应由ajax执行，我自己的代码在此事件上：

and this is a label

now i want to update a label on select of dropdown or change in dropdown and the updation shou ld be performed by ajax and i hv my own code on this event:

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
   {
       int factor = DropDownList1.SelectedIndex + 1;
       int pricein = int.Parse(Label2.Text);
       int totalPrice = pricein * factor;
       Label2.Text = totalPrice.ToString();
   }

推荐答案

设置 AutoPostBack =true。

<asp:label id="Label2" runat="server" xmlns:asp="#unknown">Text="Label"></asp:label>

这里文本 标签是 Label 并在以下行中将其解析为整数。

Here Text of Label is "Label" and in the following line you are parsing it to integer.

int pricein = int.Parse(Label2.Text);

什么将是输出？ :)



同样如 thatraja 建议，你应该设置 AutoPostBack =true for DropDownList 以便触发 DropDownList1_SelectedIndexChanged 事件。

What will be the output? :)

Also as thatraja suggested, you should set AutoPostBack="true" for DropDownList in order to fire DropDownList1_SelectedIndexChanged Event.

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