Sample ASP.net 2.0' Client callback : The Official Microsoft ASP.NET Forums

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mikepope

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Re: Sample ASP.net 2.0' Client callback

Aug 26, 2005 04:57 AM|LINK

Shoot -- I've been having problems with connectivity on my server.

Here's the code. Code-behind for the page:

Partial Class CallBack_DB_aspx
    Implements System.Web.UI.ICallbackEventHandler

    Protected ZipTable As Hashtable
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) _
            Handles Me.Load
        ZipTable = New Hashtable()
        ZipTable.Add("98106", "Seattle")
        ZipTable.Add("10270", "New York")
        ZipTable.Add("95110", "San Jose")

        Dim cbReference As String = Page.GetCallbackEventReference(Me, _
            "arg", "GetServerData", "context")
        Dim callbackScript As String = ""
        callbackScript &= "function CallTheServer(arg, context)"
        callbackScript &= vbCrLf & "{"
        callbackScript &= vbCrLf & "    " & cbReference & ";"
        callbackScript &= vbCrLf & "}"
        Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), _
            "CallTheServer",  callbackScript, True)
    End Sub

    Public Function RaiseCallbackEvent(ByVal eventArgument As String) _
            As String Implements _
            System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
        Dim city As String
        If ZipTable(eventArgument) Is Nothing Then
            city = "Not found"
        Else
            city = ZipTable(eventArgument).ToString()
        End If
        Return city
    End Function
End Class

Here's the page:

<%@ Page Language="VB" AutoEventWireup="false" 
    CompileWith="CallBack_DB.aspx.vb" ClassName="CallBack_DB_aspx" %>

<html>
<head runat="server">
<script type="text/javascript">
function CityLookup()
{
   var zip = document.forms[0].zip.value;
   CallTheServer(zip, "");
}

function GetServerData(city, context)
{
   document.forms[0].city.value = city;
}
</script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <input type="text" id="zip" />
    <br />
    <button onclick="CityLookup()">Look up city</button>
    <br />
    <input type="text" id="city" />
    </div>
    </form>
</body>
</htm>

-- Mike Pope

ASP.NET User Education

This posting is provided "AS IS" with no warranties, and confers no rights.

mikepope

Re: Sample ASP.net 2.0' Client callback

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