Variable Hides A Variable In An Enclosing Block Error
May 14, 2010
have a look at this simple code snippet
[Code]....
Here second declaration of x gives error that "variable 'x' hides a variable in an enclosing block. I wonder why this error is not given for second 'i' variable declared in second for loop?
Since i am declaring second x in a separate for block, why this error is given for variable second x ?
I'm am not quite sure why I am getting this error.
Dim numUsers as Integer Using myConnection as New System.Data.SqlClient.SqlConnection("Data Source=(local);InitialCatalog=dbtest;Integrated Security=True") Dim queryString As String = "SELECT COUNT(*) AS Num_Of_User FROM tblusers WHERE username=@username AND password=@password" Using myCommand as New System.Data.SqlClient.SqlCommand(queryString, myConnection) myConnection.Open myCommand.Parameters.AddWithValue("@username", requestName) myCommand.Parameters.AddWithValue("@password", requestPass) numUsers = myCommand.ExecuteScalar() End Using End Using
I have 2 separate code-block asp.Net expressions in an aspx markup, with an html content between (span element in the example below). In the first code-block, there is "i" as an increment variable for the for loop.Then the code-block is cut with an html content.And another code-block expression is opened but as I see I can reach the "i" variable which was declared in the previous code-block.
So, how asp.net handles -compiles- the pieces of code-block experrions declared in the mark up? Does it check the semi-colons and generates some anonymous methods which will end up with many calls to Response.Write in the last place? <p> <%for (int i = 0; i < 30; i++) {
I am using three listviews on a page ... the first is always populated ... the other two are sometimes populated I want to total amounts and counts from all three ... so I set up steps in the DataBound events works great when all three listviews are populated the error "Object Variable or With block variable not set." occurs when LV2 or LV3 is not populated I've tried testing DataItem ... Is Nothing but get the failure on the If test instead
Nested GridView Control returns "Object variable or With block variable not set" when outer GridView returns rows.
The Nested GridView Control works as long as the outer GridView returns rows, the following code works: [Code]....
Object variable or With block variable not set.
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.NullReferenceException: Object variable or With block variable not set.
Source Error:
Line 118: If e.Row.RowType = DataControlRowType.DataRow Then Line 119: Dim myStatus_ID As SqlDataSource = CType(e.Row.FindControl("sqlDeviceStatusAssign"), SqlDataSource) Line 120: If Not e.Row.DataItem("Status_ID") Is Nothing Then Line 121: myStatus_ID.SelectParameters(0).DefaultValue = e.Row.DataItem("Status_ID") Line 122: End If
I have tried checking for IsDbNull and checking to see if a label exists in a given row. This code *If Not e.Row.DataItem("Status_ID") Is Nothing Then* appears to do nothing.Same with the following:
*Dim localLblItemReference As Label = CType(e.Row.FindControl("lblItemReference"), Label)
To further clarify my question above, I am looking for a method to detect e.Row.DataItem("Status_ID") is nothing/null due to the outer GridView returning 0 results in a query.I have a (Outer) GridView Control with another GridView Control inside of a template field with it's associated SqlDataSource control.
In the "Protected Sub GridViewReport_RowCreated", I provide the Select Parameter for the associated SqlDataSource with the DataItem row value.When the (Outer) GridView Control does not return any rows, the "e.Row.DataItem("Status_ID")" throws a:
Exception Details: System.NullReferenceException: Object variable or With block variable not set.
I was wondering, if I create a page e.g. index.aspx and I create it's contents based on a variable, would an AdSense block always show the same ad? Meaning is there a way to give it a dynamic content and having the ad addept to the content without creating a page for each content.For example I have a site with 3 links: pears, apples and lemons. I have a database which has the content of each page. I have a dynamic page index.aspx which modifies it's content based on the clicked link (the link always returns to index.aspx). If I want an ad to match my content, should I then do it differently? Like creating pages for each link and adding the content to each page dynamicly based on the link or something?
I have a web application which uses a session variable to store the logged in userid. If no user is logged in, of course this variable will be empty and the contents displayed on my website are meant for guests. If there is a user logged in, the user specific controls/access/links will then be a displayed.
I am now having issues with my hosting where on shared application pool, the worker recycle is triggered every 90 minutes, this will clear sessions causing all my users to be logged out. I opted for a dedicated application pool, which got worse because I am only allocated 50MB memory limit and if this is reached, the worker recycle is triggered and I lose my sessions again. I have tried as much as possible optimization techniques, e.g. dispose where possible, close connections, disable viewstate for static controls etc but my memory per instance keeps building up from page to page without any signs of improvement. I don't use loops nor store huge objects like bitmaps etc but my sessions are now gone even faster than 90 minutes in shared application pool before.
I have considered using SQL Session State but there isn't a simple guide on using this with MySQL. I am getting desperate and considering using a public variable, a string as a replacement to store logged in user id instead of in a session variable. I am pretty sure this will solve my issue with sessions being recycled but are there any negative consequences of doing this? One problem I can think of is if the user closes the browser, the system will never know that the user is now logged out and this public variable should be nothing. In this scenario, will the GC eventually clear this abandoned public variable.
I got a variable of type System.Drawing.Image and need to convert it to a variable of type byte so I can store the image in the database. Can someone show me how to do that in VB.NET code.
I'm evaluating two options of accessing a server side data on client side. Little bit confused about the efficiency or may be you can call it as finding best approach to do it.
I need to access a server side data may be an integer value in javascript on client side. I know about two options to do it.Create a public variable or property on server side and set it to javascript variable on client side as below:
var value = eval(<% =value %>);
Create a asp hidden variable and set value in this hidden variable from server side and access it through javascript using document.getElementById().
Which is the best approach and what are the pros and cons?
Possible Duplicate: Use of var keyword in C# Hi, I am pretty new in C#,I would like to know the best practices in declaring variables.I know it is possible to use VAR (explicit declaration) or the DataType when declaring a variable (implicit).
What would be the proper syntax in ASP.NEt 3.5 C# to assign a TextBox value to a temporary or session variable to be manipulated (added, subtracted, multiplied, divided) at different points in the application? I want to add a decimal number to this variable in almost every instance as well.
I have the dataset. in this i am having total 20 tables with huge amount of data..I want use this data over all the page..so where i can keep this data..
before i used viewstate but the viewstate data is render to page every postback ..so this time the page size is increasing(interanlly viewstate is rendered to page)..so performence wise it was very slow..
Now i change my logic insted of viewstate to i used Globel Dataset on Page Level.. now the performence wise better than viewstate..
i used Like shared dsControls as Dataset at top of the page..so every time i use this dataset..
my quesation is session is better or Globel variable is better way use in my situavation..
I am having one doubt regarding the use of static variable in Asp.net pages.I am having one page say UserDetails.aspx.In this page, I have one static variable to store some data specific to a user. So, will this ?
public partial class UserDetails { static int numberOfReviews=0;
when I am executing an above code and click on button to insert data is shows an error message
as: System.Data.SqlClient.SqlException: Must declare the scalar variable "@imagefile"
Protected Sub button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles button1.Click Try If fileupload1.HasFile Then 'getting length of uploaded file
Currently in an .aspx file, I am storing a value (filename that was created in that session) in an hidden text box. When the user clicks on the "Print" labeled Hyperlink control, it opens the file that was stored in the hidden text box control. But when the user goes to different screen (in the same session), I loose the filename value that is stored in the hidden text box control. So I would like to store the filename variable in a session variable. So that if the user leaves this .aspx file and comes back to this .aspx file I can load the value into the hidden text box from the session variable.
I get a casting error on line #8 below which reads "db.UserID = Session("UserID")". What would be the correct way to cast this? The datatype of the DB field is GUID.
I want to add my own session variable to elmah error log table and display it. I already have modified the source code and added the new fields to Error.cs and other fields but I don't know but when I assign an HttpContext.Current.Session["MyVar"].tostring() value to my field in the constructor it stops logging exceptions and does not log any exception. I just need to get the value of the session variable is there other way for this ? I read a post which he added fields for the email but it does not say where exactly should I get the session value. I also read that Session and Cookies ar e logged by default by Elmah but I dont know how to access them.
OK, this may be a little difficult to explain, so I will try my best and post the code I currently have.
I have a table with a list of usernames. I have the list of usernames displayed on a page through a GridView. What I am attempting to do is for each username in the column "adminUsernames", I need to insert a set of values in another database table for EACH "adminUsernames" that exists. Example: There are 2 adminUsernames vales in 2 seperate rows. These are "Admin 1" and "Admin 2". For each adminUsername values (Admin 1, Admin 2), I need a row interted in another database table. Maybe the code that I have (that does not work) will help you see what is happening:
[Code]....
I keep receiving this error when running: [Code]....
Code: Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load Try Response.Write(Session("ValidUser").ToString & "<br />") Catch ex As System.Exception Response.Write("Valid User Session Variable Not Found: " & ex.ToString & "<br />") End Try
[Code] .....
This the page that users are redirected to after logging on and, after verifying their credentials at the log-on stage, should show 'Hello DonaldDuck@Disney.com, Welcome to my website'.
Do these errors mean that the user cannot be validated in the database?