I want to know how to handle the concurrency throughy code ? ie: I want to access the Concurrency issue or error ? Because if i get the concurrency user or issue I have to do some manipulation.
View 4 RepliesI have myPage.aspx and I am adding user control "myUserControl.aspx" to it dynamically. myPage.aspx also has <asp:Button />
myUserControl.ascx has <asp:DropDownList .... PostBack="true"/>
I am doing something in load event of myPage.aspx which I don't want to do when PostBack is originated from the user control
Following is the load event of myPage.aspx
[Code]....
With javascript, how do I check for a user clicking the back arrow in a browzer?
View 5 RepliesHere is the code copied from [URL] In asp.net code behind, I use try-catch try to catch any error but never catch it. In SQL database, if I rename Employees to Employeesx or change column DepartmentID to DepartmentIDx, record will not be deleted (it is right) without any error (it is wrong, suppose catch an error).
CREATE PROCEDURE DeleteDepartment
(
@DepartmentID int
)
AS
BEGIN TRANSACTION
DELETE FROM Employees
WHERE DepartmentID = @DepartmentID
IF @@ERROR <> 0
BEGIN
ROLLBACK
RAISERROR ('Error', 16, 1)
RETURN
END
DELETE FROM Departments
WHERE DepartmentID = @DepartmentID
IF @@ERROR <> 0
BEGIN
ROLLBACK
RAISERROR ('Error', 16, 1)
RETURN
END
OMMIT
i am trying to save last user logon on database,the event will done when user logout or close browser
i tried to call web_service on javascript but in vain,the javascript doesnt see the webService,but i added reference to ScriptManager
[Code]....
i got username from the cookie,i access the DB to update his table.
the question as iam beginner on asp
where and when to use this method,when to cupture the user's web browser close,
how to do this in aspx.cs code behind "iam not good at JS"
and i want to know? when the user close the browser or page? am i still connecting with him to make changes as his account(cookie)?
I get this error in the browser:
Code:
Thread was being aborted.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Threading.ThreadAbortException: Thread was being aborted.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[ThreadAbortException: Thread was being aborted.]
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +486
System.Web.ApplicationStepManager.ResumeSteps(Exception error) +501
System.Web.HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +123
System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +379
Version Information: Microsoft .NET Framework Version:2.0.50727.3053; ASP.NET Version:2.0.50727.3053
I have try{}catch(Exception ex){} in the right place:
Code:
protected void Button1_Click(object sender, EventArgs e)
{
try
{
// all processing occurs inside here
}
catch(Exception ex)
{
}
}
I even created a global.asax file and on the Application_Error event, I wrote a code that would email me the error (and i'm not getting an email regarding that error when I get the error shown above). I know for a fact that the thread is going inside the "try" statement because I send emails to myself whenever it finishes certain codes inside of it. So how come I'm getting that error in my browser instead of it being handled in my "catch" statement? I have two problems here, one, why is the exception not going to my "catch" statement, and two, why am I getting that error in the first place.
Note: my web app calls a webservice.
I have a couple of questions on exception handling in .net: 1- Why do we have to catch specific exceptions other than the reason of displaying a particular error to the user? What if we wanted to always display a generic error to the user and not give him much details, would it be okay to catch only generic xceptions?
2- Is throwing exceptions from the data access layer to the UI layer best practice, or is it recommended to return a string or perhaps a boolean values from the data access layer to the UI layer?
I have text box get data from dataread. Here my code:
OleDbCommand com = new OleDbCommand("select sid from TableOne where pid = " + "'" + PID.SelectedValue + "'" + " and gid = " + "'" + GID.SelectedValue + "'" + " and unitid = " + "'" + tid.SelectedValue + "'");
........
........
Txtsid.Text = myDataReader[0].ToString().Trim();
I got the run time error at line: Txtsid.Text = myDataReader[0].ToString().Trim(); Invalidoperationexception was unhandled by user code. No data exists for the row/column. How to try catching those errors?
i have a hotle reservation system.
when a user select a room i want that it lockes and an other person can not select it.
i think it`s better that i have a flag in my table and when a user select room value of is false and if cancle reservation ,i changed it true.an other person can see room that they have true value .
How to control concurrent requests for web sites?
View 1 RepliesIn what way is used optimistic concurrency?
I need to connect two tables together.
If you use optimistic concurrency at the same time, users will store data in a table?
In particular, I wonder what the difference is, if I save the aspx, or use optimistic concurrency.
My project includes a grid view with some updtable fields, some fields throw an error on update and some do not and it does not really make sense. WORK_STATION_ID does not cause an error, ROOM _ID cause an error, both are int? (I am using c#) and for update I use the code liste below.
[Code]....
[Code]....
I am trying to handle concurrency in my application. Basically if user A has a support ticket open which currently has a status of 'Active' and user 'B' opens the same ticket and closes it (changing its status to closed), I would expect a confict execepton to be thown when user 'A' tries to close the support ticket. For some reason this is not happening. I have checked that Update check is set to 'Always' in the dbml file. Here is an exerpt of my code. // Update 'Active' lead to 'Close'
[Code]....
I have the following problem:- I have a Settings table which has a value column, that is incremented everytime a Job is created (I use Entity framework to add the job and to update the value increment). So, I have something like this:
[Code]....
The problem is: I have a asp.net with concurrent calls to SaveJob Method. In this code, the value is shared, and if I call SaveJob 5 times for instance, the value column is 3, because the scope is not "locking" the other transactions until It's done, and the value is shared. I want to have the following scenario: Call SaveJob 5 times;Value column in Settings table is 5;Call SaveJob 3 more times;Value Column in Settings table is 8. I tried to implement something like pessimistic concurrency in EF, but I had no success. Whats the best way to handle that without using SQL Server queries directly? (like 'lock' and 'unlock' etc)
I tried to implement Optimistic Concurrency in the Movie MVC 3 project.
1. I added a new property
[Timestamp]
[ConcurrencyCheck]
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public byte[] RowVersion { get; set; }
2. Modified controller to execute
var movie = db.Movies.Find(model.Id);
db.Movies.Attach(movie);
TryUpdateModel(movie);
db.SaveChanges();
return RedirectToAction("Index");
3. Added the RowVersion as a hidden field to the View page
@Html.HiddenFor(model => model.RowVersion)
It didnot work for me, can someone pls point me to the right direction?
i am in the process of creating a restful service with WCF, the service is likely to be consumed by at least 500 people at any given time. What settings would i need to set in order to deal with this.
Here is a sample of what i have so far;
[Code]....
And this is an example of a method being called;
[Code]....
I've been quite impressed with dynamic data and how easy and quick it is to get a simple site up and running. I'm planning on using it for a simple internal HR admin site for registering people's skills/degrees/etc.
I've been watching the intro videos at www.asp.net/dynamicdata and one thing they never mention is how to handle concurrency control.
It seems that DD does not handle it right out of the box (unless there is some setting I haven't seen) as I manually generated a change conflict exception and the app failed without any user friendly message.
Anybody know if DD handles it out of the box? Or do you have to somehow build it into the site?
I have an application, that is accessing by number of users at the same time. Those users, who are accessing the application getting the same id. Here what i am doing in the code is, when they are creating new user i am getting a max id from DB and increasing the value to 1. So that they are getting same ID. so that i am facing concurrency in this situation. How to solve this problem. I need to display different numbers when the users click on NewUser. I am using SQL server 2008 and .NET 3.5 and C#.NET
View 2 RepliesActaully i developed an Asp.net website which has a PDA app part. The case is that employees from company come in the morning and get data in their PDA's and they work on them the whole day and in Evening they again come to office or from any web access they update the data on server. We did this through Web services because web services are remote methods so they could access that by only web access..
Now the problem is Concurrency that while syncing through web servies how to control Concurrency however their could be many employee who try to update data at a time.In web servies we receive DataTable from PDA application and do update or insert operations through LINQ with Sql Server.
Made my first application in aspx, and connect to mysql, the issue is how concurrency control (transactions), ie that when users log dam not, nor information loss...
View 3 RepliesHow should I solve simulation update, when one user updates already updated entery by another user?
First user request 'Category' entityobject, second user does the same. Second user updates this object and first user updates. I have field timestamp field in database that wa set to Concurrency Mode - Fixed.
This is how I update:
[Code]....
Exception never jumps...How should I handle this?
I have an online flight reservation system that users can reserve flight ticket,my problem is in concurrency,i have a 'remaincapacity' field in my flight table(keep flight properties) and when a user want to get a ticket i first check this field an if the value is greater than number of ticket that user requested i subtract 'remaincapacity' and after that i allow user to reserve that ,how do in control concurrency?
View 2 RepliesI added a column of type "timestamp" to a table in SQL Server to use for concurrency control. I deleted all my tables from the Linq surface and then added them back. I see that the "Time Stamp" attribute is set to True for the timestamp column and False for all the other columns. I also see that the "Update Check" attribute is set to Never for all columns, including the timestamp column.
After watching some demo videos and reading some tutorials, I had expected to have to manually set the "Update Check" attribute values on the columns - to Never for all columns but the timestamnp column where it should be set to Always. But, before setting the "Update Check" to Always on the timestamp column, I decided to test it the way it was, and Linq seems to be doing the right thing - it seems to be using the timestamp column for concurrency control correctly even with "Update Check" set to Never on the timestamp column.
So my question is - does the fact that "Time Stamp" is set to True trump the "Update Check"? Or is there any other reason one could or should set "Update Check" to Always on a timestamp column? Is there any change in behavior?
I have a strange problem in my ASP.Net 3.5 application. When multiple users try to access the same page (which has some long running methods), the application crashes at a point where it tries to open a connection to the database (a static method inside a static class). It appears that the connection is already open. However, this does not happen when there is only one user using the application. What I cannot understand is that how do actions of one user affect the other in a web application?
I double checked that all my open connections are being closed after performing their operation by appending a line of text to a text file whenever a connection is opened or closed. The number of opened and closed connections was equal. Also, the connections are opened and closed from one place only, where the close method is inside a Finally() block.
I have a property call (add user to a group) that would be hard to write code to check if user is already in group and I need to call it multiple times sometimes for the same group. anyhow it throws an error if user is already in group. easy way if to just put in a try catch and do nothing for the catch. it works fine except there are several errors in the application event log for this error when it happens. I would rather it not to log this error as it takes up time when looking in the event log to say - this is not a valid error log. so is there a way to tell a try catch to not log in the event log an error it is catching? I would rather not change any settings for the whole site but perhaps just this 1 page might be acceptable.
View 2 Replies