I have an application in ASP.Net Ajax. I want to open it via a browsercontrol from a winform, and I wish to access a variable (username) that the user used to log in to the webform with. On load I would like to read that username and perform the rest of my webpage code on that browsercontrol using that username.
My ASP.Net Ajax has been published to a internal web server and the browsercontrol loads that IP address.
Is there any way to achieve this at all?
EDIT:
I have discovered the javascript extension: window.external
And I can call a C# procedure from the webpage using javascript with it, which is a start, but I need to retrieve a varaible from c# - this is where the problem comes in. I have tried the
var name = function window.external.GetGlobalVariable(MyGlobalProcedure, "Cannot Get Value");
But javascript error says the method cannot be applied to the object.
Your answer should be as follows:
Public Class Form1
Dim GlobalVar As String = "Your Name"
Dim YourBrowser As New WebBrowser
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
YourBrowser.Url = New Uri("Your URL address")
AddHandler YourBrowser.DocumentCompleted, AddressOf PageLoadComplete
End Sub
'The invokescript will only work once the HTML has finished loading itself into your WebBrowser
Sub PageLoadComplete()
'Must declare the string inside an array as the invokescript only allows an object to be sent
Dim VarToSend As String() = {GlobalVar}
YourBrowser.Document.InvokeScript("yourJavascriptfunction", VarToSend)
End Sub
The javascript section should look as follows:
<script type="text/javascript" language="javascript">
function userNameSet(name) {
$(document).ready(function() {
//variable now exists inside your WebBrowser client and can be used accordingly now
alert(name);
});
}
</script>
References for answer: http://www.dotnetcurry.com/showarticle.aspx?ID=194
"Store that name in a session variable and access the session in your ajax call"
In your ASP.Net application create a hidden field (or if it's somewhere on the UI in some control that works also). Put the username or whatever information you want to share into that field.
From your WinForms program you can request that field through the WebBrowser control like this:
MessageBox.Show(WebBrowser1.Document.GetElementById("txtUsername").GetAttribute("value"))
The above assumes you have some HTML element called txtUsername with the value attribute set.
Related
I have a web page (aspx)- Purchasing page, with a ascx toolbar - Export Toolbar, that is used to export the data (either .xls or .csv).
I need to grab the Name of the Supplier from the Purchasing page and insert that value into the name of the export file on the ascx toolbar.
On the Purchasing page there is a ddl where the user can select the supplier and a grid that will display all the data. Above the grid there is the tool bar with an export button. I need to be able to grab the text of the dropdown list and utilize that on the ExportToolbar.ascx.vb page so I can take that text and insert it into the name.
I was trying to use a public property get and set method but it was not working. How would I go about grabbing that selected text from the Supplier ddl?
Conventional thinking goes like this: an ascx can be hosted on any aspx page. So usually it is bad form for an ascx to access properties of its host page. It is much more proper for the ascx to have a public property and the aspx will push the value into the ascx (as needed).
However, if you really want to go this route, the .Page property (of the ascx) referrs to the host page. If you cast it to the (stronger) type(name) of the host, you can get to the hosts properties. Like this:
'if your host page is called HostPage (and the class name is the same)
Dim host as HostPage = CType(me.Page, HostPage)
'now refer to the controls on the host (aspx) page
dim example as string
example = host.txtExample.Text
Keep in mind, this will cause errors if your ascx is hosted on several pages.
You can use an event form this purpose. Define the event on the UserControl like this:
Public BeforeExportEventArgs
Inherits EventArgs
Public Property FileName As String
End Class
Public Class ToolbarControl
Inherits UserControl
Public Event BeforeExport As EventHandler(Of BeforeExportEventArgs)
Public Sub btnExport_Click(sender As Object, e As EventArgs) Handles btnExport.Click
' Retrieve File Name
Dim beforeExpEventArgs As New BeforeExportEventArgs()
RaiseEvent BeforeExport(Me, beforeExpEventArgs)
' Set default filename if not provided by an event handler
If String.IsNullOrEmpty(beforeExpEventArgs.FileName) Then
beforeExpEventArgs.FileName = "DefaultFileName.csv"
End If
' Export data
End Class
Add an event handler to the form that hosts the UserControl:
Public Class WebForm1
Inherits Page
' ...
Public Sub expToolbar_BeforeExport(sender As Object, e As BeforeExportEventArgs) Handles expToolbar.BeforeExport
e.FileName = ddlSupplier.Text + ".csv"
End Sub
' ...
End Class
This way, you avoid tight coupling between the UserControl and the Page. The pages that host the UserControl can set a specific filename, but don't have to.
What I ended up doing was this-
On the ascx page I created a public property-
Public Property SupplierSelection As String
Get
Return Convert.ToString(ViewState.Item("SupplierSelection"))
End Get
Set(ByVal value As String)
ViewState.Add("SupplierSelection", value)
End Set
End Property
And then on the aspx page I added this on the load grid event-
SupergridToolbar1.SupplierSelection = ddlStrategy.SelectedItem.Text.ToString()
I was then able to use the Supplier Selection on the ascx page. Thanks for the help!
I am building a custom control with client side scripts that I would like to reference using ScriptManager.ScriptResourceMapping (to make use of the Path and DebugPath attributes).
I would like the custom control to be easily ported to other projects - i.e. I would like to drag and drop the codebehind files (and eventually make the control a separate DLL, but for now the drag and drop will suffice). I would therefore like to avoid (1) having the client script as an embedded resource, (2) referenced as a WebResource in the AssemblyInfo, or (3) have the ScriptManager.ScriptResourceMapping.AddDefinition in global.asax.
In simple terms can I get the script management code to be in just the custom control's code?
At the moment I am getting an error stating that the script reference cannot be found in the assembly, and I guess I am setting the wrong assembly.
My custom control code is as follows:
Public Class MyControl
Inherits System.Web.UI.LiteralControl
Implements ISectionControl, IScriptControl
Private _scriptReference As ScriptReference
Public Sub New()
' Add the resource mapping
ScriptManager.ScriptResourceMapping.AddDefinition("MyControlScript", New ScriptResourceDefinition With {
.ResourceAssembly = System.Reflection.Assembly.GetExecutingAssembly,
.ResourceName = "MyControlScript.js",
.Path = "Path.To.MyControlScript.minimised.js",
.DebugPath = "Path.To.MyControlScript.original.js"
})
' Set the script reference
_scriptReference = New ScriptReference("MyControlScript.js", Assembly.GetExecutingAssembly.FullName)
End Sub
Protected Overrides Sub OnPreRender(e As System.EventArgs)
MyBase.OnPreRender(e)
' Register the script
ScriptManager.GetCurrent(Page).RegisterScriptControl(Of MyControl)(Me)
' Some code to set the Text of the literal control
' ...
End Sub
Public Function GetScriptDescriptors() As System.Collections.Generic.IEnumerable(Of System.Web.UI.ScriptDescriptor) Implements System.Web.UI.IScriptControl.GetScriptDescriptors
Return New ScriptDescriptor() {}
End Function
Public Function GetScriptReferences() As System.Collections.Generic.IEnumerable(Of System.Web.UI.ScriptReference) Implements System.Web.UI.IScriptControl.GetScriptReferences
Return New ScriptReference() {_scriptReference}
End Function
End Class
I hope the question makes sense. Thanks for taking the time to read through.
Ali
Answered this myself, I was getting confused with the assemblies and the constructors for ScriptReference. I just wanted a ScriptReference with the (mapped) name so I used the blank constructor and then set Name. I could then remove the assembly information.
Adjusting the following sorted the problem out:
Public Sub New()
' Add the resource mapping
ScriptManager.ScriptResourceMapping.AddDefinition("MyControlScript", New ScriptResourceDefinition With {
.Path = "Path.To.MyControlScript.minimised.js",
.DebugPath = "Path.To.MyControlScript.original.js"
})
' Set the script reference
_scriptReference = New ScriptReference() With {.Name="MyControlScript"}
End Sub
I'm writing a WCF WebMethod to upload files to, of which I taken snippets from around the web. The WCF interface looks like this:
<ServiceContract()>
Public Interface ITransferService
<OperationContract()>
Sub UploadFile(ByVal request As RemoteFileInfo)
End Interface
<MessageContract()>
Public Class RemoteFileInfo
Implements IDisposable
<MessageHeader(MustUnderstand:=True)>
Public FileName As String
<MessageHeader(MustUnderstand:=True)>
Public Length As Long
<MessageBodyMember(Order:=1)>
Public FileByteStream As System.IO.Stream
Public Sub Dispose() Implements IDisposable.Dispose
If FileByteStream IsNot Nothing Then
FileByteStream.Close()
FileByteStream = Nothing
End If
End Sub
End Class
Within ASP.NET, when the web method is consumed, for some reason it only works when the interface is used as part of the instantiation of RemoteFileInfo:
Protected Sub btn_Click(sender As Object, e As EventArgs) Handles btn.Click
If fu.HasFile Then
Dim fi As New System.IO.FileInfo(fu.PostedFile.FileName)
' this is the line in question --------------
Dim cu As ServiceReference1.ITransferService = New ServiceReference1.TransferServiceClient()
' -------------------------------------------
Dim uri As New ServiceReference1.RemoteFileInfo()
Using stream As New System.IO.FileStream(fu.PostedFile.FileName, IO.FileMode.Open, IO.FileAccess.Read)
uri.FileName = fu.FileName
uri.Length = fi.Length
uri.FileByteStream = stream
cu.UploadFile(uri)
End Using
End If
End Sub
Can anyone advise why it is not possible to create an instance of TransferService using the following approach:
Dim cu As New ServiceReference1.TransferServiceClient()
If I try the above, it breaks this line:
cu.UploadFile(uri)
...and UploadFile must be called with three parameters (FileName, Length, FileByteStream) even there is no method that uses this signature.
Why is the Interface required when creating an instance of this class please?
When you create the proxy for your service with the "Add Service Reference" dialog, by default the proxy creation code will "unwrap" message contracts, like the one you have. If you want the message contract to appear as you defined on the server side on your proxy, you need to select the "Advanced" tab, and check the "Always generate message contracts" option. With that you'll get the message contract in your client as well.
The issue is that when a MessageContract is encountered as a parameter, the WCF client generation assumes by default that you want to implement a messaging-style interface, and provides the discrete properties from the message contract as part of the client-side interface.
The Using Messaging Contracts article in MSDN contains a very detailed description of what can be done with a messaging contract and I suspect that Microsoft chose this default behavior because of some of the "games" that you can play with the messages.
However, if you examine the code generated for your UploadFile on the client side, there are some interesting tidbits that help to explain what is going on.
The first is the comments for the UploadFile method in the interface:
'CODEGEN: Generating message contract since the operation UploadFile is neither RPC nor document wrapped.
...
Function UploadFile(ByVal request As ServiceReference1.RemoteFileInfo) As ServiceReference1.UploadFileResponse
This implies that the contract would have been generated differently if the message contract had a different implementation.
The second is that you will see that there is nothing special about the code that is used to actually make the service call:
Public Sub UploadFile(ByVal FileName As String, ByVal Length As Long, ByVal FileByteStream As System.IO.Stream)
Dim inValue As ServiceReference1.RemoteFileInfo = New ServiceReference1.RemoteFileInfo()
inValue.FileName = FileName
inValue.Length = Length
inValue.FileByteStream = FileByteStream
Dim retVal As ServiceReference1.UploadFileResponse = CType(Me,ServiceReference1.ITransferService).UploadFile(inValue)
End Sub
So in this case, your code is doing exactly what the generated code does. However, if the MessageContract were more complex, I suspect that this would no longer be the case.
So, for your question:
Can anyone advise why it is not possible to create an instance of
TransferService using the following approach...
There is no reason not to take this approach as long as you verify that the implementation of the method call is functionality equivalent to your code.
There are a couple of options for changing the default generation of the method in the client:
1) Remove the MessageContract attribute from the RemoteFileInfo class.
2) Although it seems to be counter-intuitive, you can check the Always generate message contracts checkbox in the Configure Service Reference Dialog Box.
I have a webpage where users can look for clients and select them. After selection they can be send to the webserver through an jQuery Ajax call. On the server database operations and another webservice is called, so this can take a while. That is why I wanted to present a progress bar to the user.
This progressbar is also updated by a Ajax call.
The problem seems to be that asp.net doesn't allow concurrent calls and the session state queues all calls. You can solve this in mvc by setteing the attribute [SessionState(SessionStateBehavior.ReadOnly)]
But I don't find to do this in my page-behind webmethods. Anyway, the worker method is using session state (for security, and updating the session variable for the progressbar).
The progress method is only reading and returning the session variable.
Is there a solution for it, or is another approach necessary?
I am using asp.net 4.
You could set the session mode to readonly at the #Page directive in your markup:
<%# Page Title="Home Page" EnableSessionState="ReadOnly" Language="C#" %>
I have found the solution:
1) The WebMethod only needs to receive the data and start a new thread:
<WebMethod()> _
Public Shared Function importContacts(ByVal contactGuids As String, ByVal campaignGuids As String) As String
Dim paramsList As New List(Of Object)
paramsList.Add(contactGuids)
paramsList.Add(campaignGuids)
paramsList.Add(HttpContext.Current.Session)
Dim th As New Threading.Thread(AddressOf processImport)
th.Start(paramsList)
Return ""
End Function
The Ajax call is ended quickly and on the browser you can start polling for progress.
2) The thread function needs to convert the parameters first, then you can use the session state:
Public Shared Sub processImport(params As Object)
Dim paramsList As List(Of Object) = params
Dim contactGuids As String = paramsList(0)
Dim campaignGuids As String = paramsList(1)
Dim _session As HttpSessionState = paramsList(2)
_session("EmailMarketingDatabase_progress") = 0
...
End Sub
3) The progress WebMethod looks like this:
<WebMethod()> _
Public Shared Function getProgressStatus() As Integer
Return HttpContext.Current.Session("EmailMarketingDatabase_progress")
End Function
I have the following steps in my webpage
1) User Logs in and I set the following session variables
Session("userName") = reader_login("useremail").ToString()
Session("userId") = reader_login("user_ID").ToString()
Session("firstName") = reader_login("firstName").ToString()
2) Now on my logged in VB.NET templates I reference a MasterPage called LoggedIn.Master. In Which I added the following method to check for the above null session variables. And if they null to redirect back to login page.
Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
'#Check that User is Logged in, if not redirect to login page
If (Session("userId") Is Nothing) Or (Session("userName") Is Nothing) Or (Session("firstName") Is Nothing) Then
Response.Redirect(ConfigurationManager.AppSettings("site_base_url").ToString & "login/", False)
End If
3) Now my question is if I want to use any above 3 Session variables in different .net templates or usercontrols referencing the above master page do i need to AGAIN add the check
If (Session("userId") Is Nothing) Or (Session("userName") Is Nothing) Or (Session("firstName") Is Nothing) Then
Response.Redirect(ConfigurationManager.AppSettings("site_base_url").ToString & "login/", False)
End If
In the respective pages or will the check in master page do. Because at the moment i.e. if in a usercontrol I attempt to do i.e.
customerName.Text = Session("userName").ToString()
or
Response.Write(Session("userName").ToString())
I am getting the error
Object reference not set to an instance of an object.
customerName.Text = Session("userName").ToString()
You can write a wrapper around the Session to handle null values and just call the wrapper when you access the items:
Public Class SessionWrapper
Public Shared ReadOnly Property Item()
'Access session here and check for nothing
End Property
End Class
And use it like this
SessionWrapper.Item("itemName")
In answer to your question - as long as the masterpage checks the session and redirects before all your controls and page code make a reference to Session, you should be fine.
You were using OnInit() which seems reasonable, but see this article for a good understanding of the timing of events.
Incidentally, I strongly discourage the use of ad-hoc calls to Session in your page and control code. Instead, I recommend you create a static SessionManager class that does the Session referencing for you. That way, you get to benefit from strong typing, and won't be able to accidentally make hard-to-debug 'session key' typos in your code like Session["FiirstName"]. Also, you can incorporate your null-session check right into the call for the session value:
EXAMPLE (in C#, sorry!)
public static class SessionManager
{
private static void EnsureUserId()
{
if (Session["userId"] == null)
{
Response.Redirect("YourLogin.aspx", false);
}
}
public static string FirstName
{
get
{
EnsureUserId();
if (Session["firstName"] == null)
Session["firstName"] = "";
return (string)Session["firstName"];
}
set
{
Session["firstName"] = value;
}
}
}
You can create an http module that asks about the session objects and if they are null, it will redirect to the login page and by developing this http module, in each page request the module will do the check and then you can use it normally without checking.
A better way to handle this would be to add a base class for all controls that require this session variables to be present. You can then add properties to wrap access to the session and other cool stuff and the check will work even if the controls are used with a different master page.