Question

我试图展示并获取网站访问者的坐标＆＃39;将它存储在我的数据库中的位置，我已经在javascript中使用google maps API进行了简单的试用。现在我需要将坐标值从javascript传递给我的代码以进行所需的计算并将其存储在数据库中。

这里是定位代码

   <script>
            function success(position) {
                var s = document.querySelector('#status');
                if (s.className == 'success') {
                    return;
                }
                s.innerHTML = "Gotcha!";
                s.className = 'success';

                var mapcanvas = document.createElement('div');
                mapcanvas.id = 'mapcanvas';
                mapcanvas.style.height = '400px';
                mapcanvas.style.width = '560px';

                document.querySelector('article').appendChild(mapcanvas);

                var latlng = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);

                var myOptions = {
                    zoom: 15,
                    center: latlng,
                    mapTypeControl: false,
                    navigationControlOptions: { style: google.maps.NavigationControlStyle.SMALL },
                    mapTypeId: google.maps.MapTypeId.ROADMAP
                };
                var map = new google.maps.Map(document.getElementById("mapcanvas"), myOptions);

                var marker = new google.maps.Marker({
                    position: latlng,
                    map: map,
                    title: "You are here! (at least within a " + position.coords.accuracy + " meter radius)"
                });
            }

            function error(msg) {
                var s = document.querySelector('#status');
                s.innerHTML = typeof msg == 'string' ? msg : "failed";
                s.className = 'fail';
            }

            if (navigator.geolocation) {
                navigator.geolocation.getCurrentPosition(success, error);
            } else {
                error('not supported');
            }

            //the problem is here!
            var getter = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
            document.getElementById('<%=send_laty.ClientID%>') = getter.lat;
            document.getElementById('<%=send_lony.ClientID%>') = getter.lng;
            alert(getter)


        </script>

我创建了2个隐藏字段，用于将变量从javascript传递到代码

<asp:HiddenField ID="send_laty" runat="server" Value="" />
<asp:HiddenField ID="send_lony" runat="server" Value="" />

我正在aspx.vb页面的page_load上测试它们

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    Dim output As String
    output = send_laty.Value + " ___  " + send_lony.Value
    MsgBox(output)

End Sub

但是输出是_______，这意味着变量没有传递！

我需要提示一下为什么它没有传递价值！

提前致谢，

Answer 1

您需要将结果分配给value属性。

document.getElementById('<%=send_laty.ClientID%>').value = getter.lat;
document.getElementById('<%=send_lony.ClientID%>').value = getter.lng;

Answer 2

像mga911所说的那样

aspx.vb页面的Page_Load在javascript之前执行，因此值始终为空。您需要回发值以便将数据发送回服务器

而不是使用

dim x as string = send_lony.Value

和

的document.getElementById（＆＃39;＆LT;％= send_laty.ClientID％GT;＆＃39）

我用过

dim x as string = Request.Form("send_lony")

与

document.getElementById('<%=send_laty.ClientID%>').value

我感谢你的帮助:)。

Answer 3

要使用动态控制将值从javascript传递到页面后面，请执行以下操作：

In aspx page header content,
<script language="javascript" type="text/javascript">
    function executedelete(txt) {
        alert(txt);
        document.getElementById('<%=ctlHiddenField.ClientID%>').value = txt    
        __doPostBack("<%= deletetherecord.UniqueID %>", "");                            
    }                    
</script>

在aspx页面正文内容中，

<asp:Button ID="deletetherecord" runat="server" style="display:none" />           
<asp:HiddenField ID="ctlHiddenField" runat="server" />

在Page Behind中，

Protected Sub deletetherecord_Click(sender As Object, e As System.EventArgs) Handles deletetherecord.Click
    Dim txt As String = ctlHiddenField.Value
    'do processing here        
End Sub

在Page Behind功能中，创建动态控制

SomeLabel.Text &= "<input id=""deletebutton"" type=""button"" value=""Delete"" onClick=""executedelete('" & gv.Rows(row).Cells(5).Text & "');"" />"

将代码VB.Net后面的变量从javascript传递给ASP.NET

3 个答案: