Calling Other Functions From A Shared (or Static) Function
Aug 20, 2010
I get this error: Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class.
Partial Class _Default
Inherits System.Web.UI.Page
<WebMethod()> _
Public Shared Function ParseData() As String
Dim value as string = GetValue()
End Function
Private Function GetValue() as String
Return "halp"
End Function
End Class
I know it has something to do with the fact that the first function is shared and the second function should probably be Public as well but I don't fully understand the reason behind it. Probably not relevant but I'm calling the web method from some javascript.
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Apr 30, 2010
If for example you have a function Public shared function GetStockByID(StockID as Guid) as Stock Is that function common to all current users of your application? Or is the shared function only specific to the current user and shared in the context of ONLY that current user? So more specifically my question is this, besides database concurrency issues such as table locking do I need to concern myself with threading issues in shared functions in an ASP.Net application?In my head; let's say my application namespace is MyTestApplicationNamespace. Everytime a new user connects to my site a new instance of the MyTestApplicationNamespace is created and therefore all shared functions are common to that instance and user but NOT common across multiple users. Is this correct?
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Nov 12, 2010
I want to call a non shared function in a shared function in which i am having a textbox control instance. Its giving no error but when i call this shared function from client callback it gives me no response
Any Idea except removing shared from the function.
Here is my code :
<WebMethod()> _
Public Shared Function myF() As String
Dim pg As New _Default
Return "{'Hello':'" & pg.setText & "'}"
End Function
Public Function setText() As String
Dim pg As New _Default
pg.TextBox1.Text = "This is a test"
Return pg.TextBox1.Text
End Function
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Jun 30, 2010
I did some research after posting. All I found was simple examples for no-layer architectures, like connecting to a database from your aspx page, so, in a corporate environment, it is unnaceptable.
I need to call a server-side method (using ASP.NET Ajax) in a 3-layer architecture.
For example, my Default.aspx contains a method LoadProducts().
[Code]....
[Code]....
This cannot change. There is no way to convert Business and Data layers to static.
How can I call the LoadProducts() method using ASP.NET Ajax?
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Oct 4, 2010
I have some code in my new asp.net app that I need to share. So i created a shared class called
"utilities.vb" and put it in the APP_CODE folder. There is a function I have in there that pulls a person's image based off of their MemberId.
[Code]....
And I can call this function from my page using utilities.FcnGetMemberImage(). Ok, so all good so far until it complains about...
"Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class"
when referring to the Server.MapPath()
But the problem is that if I don't make it a Shared Function, I can't access it from my other pages. But if I do make it a Shared Function, it throws this error. The fix is supposed to be that I either don't share the function, or
"add the shared keyword to the member declaration", according to Microsoft at
http://msdn.microsoft.com/en-us/library/xfsswe45.aspx
But I'm not exactly sure how to "add the shared keyword to the member declaration" or what this means exactly and how this might affect other parts of my code?
Or is there a better way to work around this dilemma?
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Jan 8, 2010
We have an application that has quite an extensive APP_Code directory (about 150 functions). The functions are split across multiple files and then classes and namespaces.
On numerous pages we have to create numerous instances of the classes to be able to access the functionality, which can get very repetitive and means we're repeating code on every page declaring the instance etc.
As far as I can tell, a way to navigate this issue, is to make the functions Public Shared (as opposed to just Public functions).
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Mar 8, 2011
I would like to write a function to reuse some functionality that I repeat over and over...
For example:
[code]....
What's changing, in every field, is only the lambda function to get the current field to edit (Name, City, Address, etc...).
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Jan 21, 2011
I have a member function that does not depend on any member variables of the class. (in my case the class is an ASP.Net Page)
The function is protected, I dont need it outside of this class. Its only purpose is to build an URL from an given object.
Should I make all my functions static if they dont depend on the class, even if they are not used outside of this class?
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Sep 28, 2010
I am trying to call some javascript functions which I ahve written in some file. Eg.
function OpenPopup() {
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return false;
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when I call this from button from OnClientClick = "OpenPopup()" it is not called but when I put this function on MasterPage it is able to call the function.I added this is the MasterPages's Head
<script src="Scripts/something.js" type="text/javascript"></script>
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Jun 4, 2010
I have an .aspx.cs page in my solution and I'm trying to call a function which is located in a Master page.Would anyone be able to offer any pointers on how to achieve this as I cannot figure it out - thought it would have been fairly straight forward!
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Nov 8, 2010
I want to check two conditions in the OnClientClick event of an asp.net button control. I tried this but it is only checking the first function.
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May 7, 2010
I'm building an online system to be used by school groups. Only one school can log into the system at any one time, and from that school you'll get about 13 users. They then proceed into a educational application in which they have to co-operate to complete tasks, and from a code point of view, sharing variables all over the place.
I was thinking, if I set up a static class with static properties that hold the variables that are required to be shared, this could save me having to store/access the variables in/from a database, as long as the static variables are all properly initialized when the application starts and cleaned up at the end. Of course I would also have to put locks on the get and set methods to make the variables thread safe.
Something in the back of my mind is telling me this might be a terrible way of going about things, but I'm not sure exactly why, so if people could give me their thoughts for or against using a static class in this situation,
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Feb 24, 2010
I have a JavaScript-based timeline which needs to use data from an SQL server. The queries and the JSON conversions have been worked out in the form of C#.NET functions within a code file related to an .aspx page. So for a complete newbie to ASP.NET, how do you set up a function call like this from JavaScript?I would love it if someone had some simple example code I could learn/get some pointers from.Edit: I am using .NET 3.5
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Mar 4, 2010
I have a base class with several derived classes. I want all of my derived classes to have the same Public Shared (static) method with their own implementation. How do I do this?
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Nov 11, 2010
For reasons I would rather not discuss, I need to create a custom authentication system for my app. I was just reviewing the system and am having some doubts if my solution is thread safe. My goal was to create a solution that would allow my app to authenticate a user one time and that users authentication info would be shared by all master pages, pages, classes, user controls, etc that are used. (But not share the same info between users) Here is my setup: PageHttpModule.cs - this is added to the web.config as a httpModule.
public class PageHttpModule : IHttpModule
{
public void Init(HttpApplication app)
{
app.AuthenticateRequest += new EventHandler(OnAuthenticateRequest);
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public void OnAuthenticateRequest(Object s, EventArgs e)
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CurrentUser.Initialize();
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public void Dispose() { }
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public static class CurrentUser
{
public static bool IsAuthenticated { get; private set; }
public static string Email {get; set;}
public static string RealName {get; set;
public static string UserId {get; set;}
public static void Initialize()
{
CurrentUser.AuthenticateUser();
}
Note: this is a scaled down version of my authentication code.
public static void AuthenticateUser()
{
UserAuthentication user = new UserAuthentication();
user.AuthenticateUser();
if (user.IsAuthenticated)
{
CurrentUser.IsAuthenticated = true;
CurrentUser.UserId = user.UserId;
CurrentUser.Email = user.Email;
CurrentUser.RealName = user.RealName;
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}
}
UserAuthentication.cs
public class UserAuthentication
{
public string Email { get; set; }
public string RealName { get; set; }
public string UserId { get; set; }
public bool IsAuthenticated { get; private set; }
public UserAuthentication()
{
IsAuthenticated = false;
Email = String.Empty;
RealName = String.Empty;
UserId = String.Empty;
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public void AuthenticateUser()
{
//do some logic here.. if the user is ok then
IsAuthenticated = true
Email = address from db
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Realname = name from db;
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I have tested between 3 different browsers and it seems to work fine, but I am still learning and don't want to make a huge mistake. If my logic is totally wrong, then how should I do it so I dont have to put user lookups on every page directly?
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[URL]
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Mar 31, 2011
I have a user control which opens a new window for some item selection. Once an item is selected on that window, the item ID should be passed to a callback javascript function in the user control. In order to have a unique callback function name in the user control (it may have multiple instances on the same page), I added the user control ID to the function name as follows (defined in the ascx file):
function OnItemSelection_<%=this.ID%>(selectedItemID)
{
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Where OnItemSelection is defined in an external js file:
function OnItemSelection(controlID, selectedItemID)
{
$(controlID).do_something(selectedItemID);
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The issue is that now I'm not sure how the new page can call the "right" function (of the user control instance where it was opened from). The only idea I have in mind so far is passing the name of the callback function in the query string:
var CallbackFunction = function(selectedItemID)
{
window.opener.<%=Request.QueryString["CallbackFunctionName"]%>(selectedItemID);
}
or maybe just the opening user control ID:
var CallbackFunction = function(selectedItemID)
{
window.opener.OnItemSelection_<%=Request.QueryString["UserControlID"]%>(selectedItemID);
}
My questions are:
1) Is it a bad practice passing javascript function names (or user control IDs) like that (I suspect it is)?
2) What could be better way to handle this scenario? Edit: Another way I'm considering now is declaring a global variable in the user control (registering it from the code behind so it'll appear only once). Then, when opening the new window, it's possible to assign the relevant function to it (OnItemSelection_<%=this.ID%>), and call it from the new window. Seems much cleaner than passing user control data through the query string.
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$(function ColorChange(ID) {
$("#" + ID).toggleClass("gridLabel");
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$(function ShowHide(GID) {
$('#' + GID).slideToggle('slow');
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And I am calling these function from onmouseover, onmouseout and onclick events of the label controls passing in the label ID as parameter. As an example:
<label id="lblWebComp" class="gridLabelDefault" onmouseover="ColorChange('lblWebComp')"
onmouseout="ColorChange('lblWebComp')" onclick="ShowHide('gvDivWC')">
Web Components
</label>
Kindly let me know if this is the best way to achieve these effects? Don't I have to right the document ready function in the jQuery code?
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Jan 7, 2011
I have a page that contains a few user controls which all use an id in a querystring. I want to change this so that the page can send the id to the user control and can call a function on the user control.
Also is it possible for the user control to get the id from the page or a control on the page as its parent?
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Jul 17, 2010
There are many repeat code in the two functions, could you tell me how to merger two functions into one function?
[code]....
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Jul 1, 2010
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$(document).ready(function() {
$.ajax({
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I have a number of pages which need to support exporting data to an Excel spreadsheet. I can generate the Excel files just fine, but I'm trying to work out how to abstract this behavior so it's easily reusable from all of the pages where I need it. My current idea is to use a static utility method, as follows:
[Code]....
The click handler where I'm calling SendExcelFile looks like this:
protected void lnkExport_Click(object sender, EventArgs e)
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List<List<string>> dataList = GatherDataForSpreadsheet();
Utility.SendExcelFile(this, "fileNameForDownload.xlsx", dataList, "MyReports");
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This code works just fine as an instance method of the calling page. As a static method, though, it doesn't work at all. When I click the button that invokes this, the browser shows the loading animations indefinitely, but never prompts for a file download.
EDIT: If I remove the call to File.Delete() at the end, the method works as expected. Does Response.TransmitFile() do the transfer asynchronously?
EDIT 2: I just needed to call Response.Flush() before I deleted the file.
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[Code]....
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[Code]....
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main.aspx.vb:
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web.config:
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