J
jslaybaugh
I am trying to bind to a GridView or DetailsView after a callback using
the ClientCallback Manager in the new .NET 2.0 framework. See below
for the HTML followed by the VB code:
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
<script type="text/javascript">
function GetEmployeeInfo(empID)
{
var Command = "employeeID:" + empID;
var context = new Object();
context.CommandName = "GetEmployeeInfo";
<%=CallbackFunctionString %>
}
function CallBackHandler(result, context)
{
if (context.CommandName == "GetEmployeeInfo")
{
document.getElementById('status').innerHTML = result;
}
}
function onError(message, context) {
alert("Exception :\n" + message);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<a href="#" onclick="GetEmployeeInfo(501);">Employee 501</a><br
/>
<a href="#" onclick="GetEmployeeInfo(502);">Employee 502</a><br
/>
<a href="#" onclick="GetEmployeeInfo(503);">Employee 503</a><br
/>
<div style="width:500px;height:500px;border:solid black
1px;background-color:gainsboro;padding:20px;">
<asp
etailsView ID="DetailsView1" runat="server"
BackColor="White" BorderColor="#E7E7FF" BorderStyle="None"
BorderWidth="1px" CellPadding="3">
</aspetailsView>
</div>
<asp:LinkButton ID="LinkButton1"
runat="server">LinkButton</asp:LinkButton>
<div id="status"></div>
</form>
</body>
</html>
-----------
Imports System.Data.SqlClient
Partial Class FancyTest
Inherits System.Web.UI.Page
Implements ICallbackEventHandler
Public CallbackFunctionString As String
Private CallbackResult As String
Public Function GetCallbackresult() As String _
Implements System.Web.UI.ICallbackEventHandler.GetCallbackResult
If CallbackResult = "error" Then
Throw (New Exception("ERROR"))
Else
Return CallbackResult
End If
End Function
Public Sub RaiseCallbackEvent(ByVal eventArgument As String)
Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
If eventArgument.StartsWith("employeeID:") Then
eventArgument = eventArgument.Split(":"c).GetValue(1)
CallbackResult = DisplayEmployeeInfo(CInt(eventArgument))
Else
CallbackResult = "Command not recognized"
End If
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Me.Load
CallbackFunctionString =
Page.ClientScript.GetCallbackEventReference(Me, "Command",
"CallBackHandler", "context", "onError", False)
End Sub
Private Function GetEmployeeInfo(ByVal EmployeeID As Integer) As
Data.DataTable
Dim cn As New SqlConnection(Global.ConnString)
Dim cmd As New SqlCommand("select * from employees where
employeeid=@employeeID", cn)
cmd.Parameters.Add("@EmployeeID", Data.SqlDbType.Int).Value =
EmployeeID
Dim da As New SqlDataAdapter(cmd)
Dim dt As New Data.DataTable()
Try
If cn.State <> Data.ConnectionState.Open Then cn.Open()
da.Fill(dt)
Return dt
Catch ex As Exception
Throw ex
Finally
If cn.State <> Data.ConnectionState.Closed Then cn.Close()
End Try
End Function
Private Function DisplayEmployeeInfo(ByVal EmployeeID As Integer)
As String
Dim dt As New Data.DataTable
dt = GetEmployeeInfo(EmployeeID)
DetailsView1.DataSource = dt
DetailsView1.DataBind()
DetailsView1.Visible = True
Return employeeid.tostring
End Function
Protected Sub LinkButton1_Click(ByVal sender As Object, ByVal e As
System.EventArgs) Handles LinkButton1.Click
DisplayEmployeeInfo(502)
End Sub
End Class
----------
My problem is that the DetailsView1.Databind() call does nothing when
called via ClientCallback. The page doesnt display the DetailsView
data. I added an ASP.NET LinkButton just to make sure the code works
and if the page POSTS BACK, it works, but if it does a CALLBACK,
nothing happens. Also, since the function that does the databind
returns the EmployeeID as a string, I know the code is executing,
because the page displays the EmployeeID. Its strictly the Databind
that doesnt work.
I thought I had a pretty good understanding of the page lifecycle, but
this one confuses me. I noticed by looking at the page source that
before the postback, the detailsview doesnt even exist on the client,
so i'm not surprised that we cant quickly modify it on the client, but
I thought the whole point of this AJAX stuff was that I could execute
server code asynchronously.
Sure, I can return strings and pre-formatted HTML to create a table or
something, but I want to use the power of the ASP.NET controls such as
DetailsView and GridView. This really isnt much of a feature to
ASP.NET if you cant use all the powerful controls. If i have to
generate raw HTML, I am just left with a (quicker) version of classic
ASP content generation.
Please help!!!
Jorin
the ClientCallback Manager in the new .NET 2.0 framework. See below
for the HTML followed by the VB code:
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
<script type="text/javascript">
function GetEmployeeInfo(empID)
{
var Command = "employeeID:" + empID;
var context = new Object();
context.CommandName = "GetEmployeeInfo";
<%=CallbackFunctionString %>
}
function CallBackHandler(result, context)
{
if (context.CommandName == "GetEmployeeInfo")
{
document.getElementById('status').innerHTML = result;
}
}
function onError(message, context) {
alert("Exception :\n" + message);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<a href="#" onclick="GetEmployeeInfo(501);">Employee 501</a><br
/>
<a href="#" onclick="GetEmployeeInfo(502);">Employee 502</a><br
/>
<a href="#" onclick="GetEmployeeInfo(503);">Employee 503</a><br
/>
<div style="width:500px;height:500px;border:solid black
1px;background-color:gainsboro;padding:20px;">
<asp
etailsView ID="DetailsView1" runat="server"BackColor="White" BorderColor="#E7E7FF" BorderStyle="None"
BorderWidth="1px" CellPadding="3">
</asp
etailsView></div>
<asp:LinkButton ID="LinkButton1"
runat="server">LinkButton</asp:LinkButton>
<div id="status"></div>
</form>
</body>
</html>
-----------
Imports System.Data.SqlClient
Partial Class FancyTest
Inherits System.Web.UI.Page
Implements ICallbackEventHandler
Public CallbackFunctionString As String
Private CallbackResult As String
Public Function GetCallbackresult() As String _
Implements System.Web.UI.ICallbackEventHandler.GetCallbackResult
If CallbackResult = "error" Then
Throw (New Exception("ERROR"))
Else
Return CallbackResult
End If
End Function
Public Sub RaiseCallbackEvent(ByVal eventArgument As String)
Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
If eventArgument.StartsWith("employeeID:") Then
eventArgument = eventArgument.Split(":"c).GetValue(1)
CallbackResult = DisplayEmployeeInfo(CInt(eventArgument))
Else
CallbackResult = "Command not recognized"
End If
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Me.Load
CallbackFunctionString =
Page.ClientScript.GetCallbackEventReference(Me, "Command",
"CallBackHandler", "context", "onError", False)
End Sub
Private Function GetEmployeeInfo(ByVal EmployeeID As Integer) As
Data.DataTable
Dim cn As New SqlConnection(Global.ConnString)
Dim cmd As New SqlCommand("select * from employees where
employeeid=@employeeID", cn)
cmd.Parameters.Add("@EmployeeID", Data.SqlDbType.Int).Value =
EmployeeID
Dim da As New SqlDataAdapter(cmd)
Dim dt As New Data.DataTable()
Try
If cn.State <> Data.ConnectionState.Open Then cn.Open()
da.Fill(dt)
Return dt
Catch ex As Exception
Throw ex
Finally
If cn.State <> Data.ConnectionState.Closed Then cn.Close()
End Try
End Function
Private Function DisplayEmployeeInfo(ByVal EmployeeID As Integer)
As String
Dim dt As New Data.DataTable
dt = GetEmployeeInfo(EmployeeID)
DetailsView1.DataSource = dt
DetailsView1.DataBind()
DetailsView1.Visible = True
Return employeeid.tostring
End Function
Protected Sub LinkButton1_Click(ByVal sender As Object, ByVal e As
System.EventArgs) Handles LinkButton1.Click
DisplayEmployeeInfo(502)
End Sub
End Class
----------
My problem is that the DetailsView1.Databind() call does nothing when
called via ClientCallback. The page doesnt display the DetailsView
data. I added an ASP.NET LinkButton just to make sure the code works
and if the page POSTS BACK, it works, but if it does a CALLBACK,
nothing happens. Also, since the function that does the databind
returns the EmployeeID as a string, I know the code is executing,
because the page displays the EmployeeID. Its strictly the Databind
that doesnt work.
I thought I had a pretty good understanding of the page lifecycle, but
this one confuses me. I noticed by looking at the page source that
before the postback, the detailsview doesnt even exist on the client,
so i'm not surprised that we cant quickly modify it on the client, but
I thought the whole point of this AJAX stuff was that I could execute
server code asynchronously.
Sure, I can return strings and pre-formatted HTML to create a table or
something, but I want to use the power of the ASP.NET controls such as
DetailsView and GridView. This really isnt much of a feature to
ASP.NET if you cant use all the powerful controls. If i have to
generate raw HTML, I am just left with a (quicker) version of classic
ASP content generation.
Please help!!!
Jorin