我有一个带有c＃代码隐藏的asp.net页面。如果更改gridview对象的selected-index而不选择“confirm”或“cancel”，我试图让代码隐藏显示为“alert”。用于检测是否已选择确认或取消的代码正在运行，但我的消息永远不会显示。 'Alert.Show'代码来自：http://archive.devnewz.com/devnewz-3-20061129JavaScriptAlertShowmessagefromASPNETCodebehind.html。
例如，在从page_load（）测试时，Alert.show工作得很好，但在我的selected_index_changed方法中没有。知道为什么吗？也许与Alert.Show（）的实现方式有关？
if (ChangeAttemptedId && !IsSavedId)
{
Alert.Show("Dispatch assignment saved, but you forgot to click Confirm or Cancel!)");
}
ASP.NET代码：
<asp:Table ID="Table1" runat="server" CssClass="DefaultTable">
<asp:TableRow runat="server">
<asp:TableCell runat="server" Width="50%" VerticalAlign="Top" HorizontalAlign="Left">
<asp:UpdatePanel ID="detailsUP" runat="server" UpdateMode="Always" ChildrenAsTriggers="True">
<ContentTemplate>
<!--
<asp:Label ID="label1" runat="server" Text="Car To Dispatch: " CssClass="DefaultLabel"></asp:Label>
<asp:DropDownList ID="CarsDDL" runat="server" DataSourceID="VehiclesEDS" DataMember="CarNum" DataTextField="CarNum" AppendDataBoundItems="True" Font-Bold="True">
<asp:ListItem Selected="True" Text="-"></asp:ListItem>
</asp:DropDownList>
-->
<asp:DetailsView ID="RideToAssignDV" runat="server" Height="400px"
Width="400px" AutoGenerateRows="False"
BackColor="White" BorderColor="#999999" BorderStyle="None" BorderWidth="1px"
CellPadding="3" GridLines="Vertical">
<AlternatingRowStyle BackColor="#DCDCDC" />
<EditRowStyle BackColor="#008A8C" Font-Bold="True" ForeColor="White" />
<Fields>
<asp:BoundField DataField="AssignedCar" HeaderText="Car"
SortExpression="AssignedCar" NullDisplayText="---" />
<asp:BoundField DataField="Name" HeaderText="Name"
SortExpression="Name" NullDisplayText="---" />
<asp:BoundField DataField="Phone" HeaderText="Phone"
SortExpression="Phone" NullDisplayText="---" />
<asp:BoundField DataField="NumPatrons" HeaderText="Size"
SortExpression="NumPatrons" NullDisplayText="---" />
<asp:BoundField DataField="PickupAddress" HeaderText="Pickup Address"
SortExpression="PickupAddress" NullDisplayText="---" />
<asp:BoundField DataField="DropoffAddress" HeaderText="Drop-Off Address"
SortExpression="DropoffAddress" NullDisplayText="---" />
<asp:BoundField DataField="CreatedBy" HeaderText="Created By"
SortExpression="CreatedBy" NullDisplayText="---" />
<asp:BoundField DataField="TimeOfCall" HeaderText="Call Time"
SortExpression="TimeOfCall" ReadOnly="True" NullDisplayText="---" />
</Fields>
<FooterStyle BackColor="#CCCCCC" ForeColor="Black" BorderStyle="Inset" BorderColor="#C6940D" HorizontalAlign="Center" Height="25px" />
<FooterTemplate>
<asp:Button ID="confirmButton" runat="server" Text="Confirm" ForeColor="Green" HorizontalAlign="Center" OnClick="confirmButton_Click"/>
<asp:Button ID="cancelButton" runat="server" Text="Cancel" ForeColor="Red" HorizontalAlign="Center"
OnClick="cancelButton_Click" OnClientClick="displayTopTen();" />
</FooterTemplate>
<HeaderStyle BackColor="#004812" Font-Bold="True" />
<PagerStyle BackColor="#999999" ForeColor="Black" />
<RowStyle BackColor="#EEEEEE" ForeColor="Black" />
</asp:DetailsView>
</ContentTemplate>
</asp:UpdatePanel>
</asp:TableCell>
<asp:TableCell runat="server" Width="50%">
<asp:UpdatePanel ID="mapUP" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<div id="map_canvas" style="height: 400px; width:400px;"></div>
</ContentTemplate>
</asp:UpdatePanel>
</asp:TableCell>
</asp:TableRow>
</asp:Table>
<br />
<asp:Label ID="GV_Label1" runat="server" Text="Car To Dispatch: " CssClass="DefaultLabel"></asp:Label>
<asp:UpdatePanel ID="SelectCarUP" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:GridView ID="VehiclesGridView" runat="server" AllowPaging="True"
AllowSorting="True" DataSourceID="VehiclesEDS" AutoGenerateColumns="False"
onselectedindexchanged="VehiclesGridView_SelectedIndexChanged"
BackColor="White" BorderColor="#999999" BorderStyle="None" BorderWidth="1px"
CellPadding="3" GridLines="Vertical" ShowHeaderWhenEmpty="True" AutoPostBack="True">
<AlternatingRowStyle BackColor="#DCDCDC" />
<Columns>
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:LinkButton ID="GVSelectButton" runat="server" CausesValidation="False"
CommandName="Select" Text="Select"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="CarNum" HeaderText="Car" ReadOnly="True"
SortExpression="CarNum" />
<asp:BoundField DataField="CurrPassengers" HeaderText="Passengers"
ReadOnly="True" SortExpression="CurrPassengers" />
<asp:BoundField DataField="MaxPassengers" HeaderText="Capacity" ReadOnly="True"
SortExpression="MaxPassengers" />
<asp:BoundField DataField="Status" HeaderText="Status" ReadOnly="True"
SortExpression="Status" />
<asp:BoundField DataField="StartAdd" HeaderText="Pick-Up Address"
ReadOnly="True" SortExpression="StartAdd" />
<asp:BoundField DataField="EndAdd" HeaderText="Drop-Off Address"
ReadOnly="True" SortExpression="EndAdd" />
<asp:BoundField DataField="AvgRideTime" HeaderText="Avg. Ride Time"
ReadOnly="True" SortExpression="AvgRideTime" />
</Columns>
<FooterStyle BackColor="#CCCCCC" ForeColor="Black" />
<HeaderStyle BackColor="#004812" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#999999" ForeColor="Black" HorizontalAlign="Center" />
<RowStyle BackColor="#EEEEEE" ForeColor="Black" />
<SelectedRowStyle BackColor="#C6940D" Font-Bold="True" ForeColor="White" />
<SortedAscendingCellStyle BackColor="#F1F1F1" />
<SortedAscendingHeaderStyle BackColor="#C6940D" />
<SortedDescendingCellStyle BackColor="#CAC9C9" />
<SortedDescendingHeaderStyle BackColor="#9F770B" />
</asp:GridView>
</ContentTemplate>
</asp:UpdatePanel>
答案 0 :(得分：24)
假设我理解你的问题。
您可以使用ScriptManager来显示javascript提醒信息。
protected void Page_Load(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(),
"err_msg",
"alert('Dispatch assignment saved, but you forgot to click Confirm or Cancel!)');",
true);
}
答案 1 :(得分：4)
private void MessageBox(string message,string title="title")
{
ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(), title, "alert('" + message + "');", true);
}
它很有用： http://www.codeproject.com/Questions/311503/How-to-use-javascript-alert-message-in-code-behind
答案 2 :(得分：2)
如果您希望在页面加载时运行单个客户端JavaScript，则可以在代码隐藏中注册启动脚本：
if(!ClientScript. IsStartupScriptRegistered(typeof(Page), "alert"))
string script = "<script>";
script += "alert('";
script += "Dispatch assignment saved, but you forgot to click Confirm or Cancel!";
script += "');";
script += "</script>";
ClientScript.RegisterStartupScript(typeof(Page), "alert", script);
}
ASP.NET将负责将<script>放入HTML中并在加载页面时调用它。
答案 3 :(得分：1)
如果应通过更改索引引发asp:ListBox事件，则AutoPostBack="True"必须selected_index_changed。
例如
<asp:ListBox ID="ListBox1" runat="server"
AutoPostBack="True" OnSelectedIndexChanged="selected_index_changed">
<asp:ListItem>one</asp:ListItem>
<asp:ListItem>two</asp:ListItem>
<asp:ListItem>three</asp:ListItem>
</asp:ListBox>'
答案 4 :(得分：0)
public static void Alert(string message,Page page)
{
ScriptManager.RegisterStartupScript(page, page.GetType(),
"err_msg",
"alert('" + message + "');",
true);
}