If i have a page in which I want to check whether session is null.
If it is null it will redirect to other page.
But i also have a  if (!Page.IsPostBack)
so i will check the session inside this  if (!Page.IsPostBack) or outside it?
I have a problem with a SessionVariable. I will explain what is happening:
1. From the default.aspx I send Session["LoginByAdmin"] = "Dummy"; and then redirect to this page where I have the code below. So the Page_Load sees that this Session["LoginByAdmin"] != null and enter this page. This works fine !
2. In the Page_Load, I later fill a ListBox1 with foldernames.
3. With Button1_Click1, I will now delete the choosen Folder in the ListBox1 wich works fine the first time and the ListBox updates the new existing folders in the ListBox. (I have wrapped this inside an updatepanel)
The problems comes now when I try to delete a choosen folder in the ListBox1 the second time in a row. When I select a Folder in the ListBox1 and now Press Button1, I will be redirected to "Default.aspx". This meens that this code is running: (That meens that Session["LoginByAdmin"] == null and I have not set this to null anywhere. This is my big question how this variable can be = null here?
if (Session["LoginByAdmin"] == null)
Response.Redirect("Default.aspx");
break;
[Code]....
I have set the value of an int parameter to the attribute of a textbox.The textbox can be empty or null, how to check whether the parameter is empty or null?
View 5 RepliesHow to check the query string value null, if null then display the default value instead of object reference error.
View 1 RepliesI have some cascading dropdownlists using the ajax toolkit I have a set up datatables in an xsd file. Then use these in a webservice to populate all the fields ... this all works great but now i need to pass an additional paramter to the first dropdownlist ( a date) but don't know how to do this? The method is below...
[Code]....
The other code is:
[Code]....
The first change would be to the tableadapter to add a param to the code i.e
AuditWebDS.TeamsDataTable teams = teamsAdapter.GetTeams(calldate);
but how do i get the calldate param to the webservice method... i tried a session variable but it comes up with session is null ? Is there another better way?
So I've read quite a few posts about how to do this, and it's still getting me. I'm trying to control access to a directory, but I continue to get a null session error. I'm doing my check in PostAcquireRequestState
[Code]....no matter where I put this, my session always comes back null. I am using IRequireSessionState on the class as well. Am I pulling the context wrong?
I'm experimenting with validating forms in the asp.net MVC framework. I'm focusing on server side validation for the time being. I've come across an error that I'm not sure how to rectify. System.NullReferenceException: Object reference not set to an instance of an object. The code that throws the error is:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create([Bind(Exclude="ID")] MembersCreate mc )
{
mc.Modules = ModuleListDataContext.GetModuleList();
ViewData.Model = mc;
//Validation using ModelState
//
//
//line below errors when form field is empty
//
if ((string)mc.Member.Username.Trim() == "")
ModelState.AddModelError("Member.Username", "Username is required.");
if (!ModelState.IsValid)
return View();
try
{
// TODO: Add insert logic here
return RedirectToAction("Index","Home");
}
catch
{
return View();
}
}
When I put spaces in the field it performs exactly as i want, but if I leave the field blank and press submit I get the error. What's the best way to avoid this error and still validate blank form fields?
When using SqlDataReader.NextResult for 2 queries I am trying to I check if the second query returns any rows, but whether it has any rows or not the repeater2 is never hidden/false . I am doing something like this:
[Code]....
I have a Sql Data Source that queries my class database. What I'm trying to do to save myself some landscape is to check a checkbox if any of the pre-requisite fields are not empty. I have this laying inside a gridview. My code doesn't error out but it doesnt' do anything either.
[Code]....
My query is like this:
[Code]....
So in a nutshell, if there is any value in PR1 - PR7, I want to check my checkbox in the gridview.
how come a Null session value that is called, doesn't get directed to the Custom Error Page?
View 4 RepliesI need to pass some values around using session state. My approach is to first check if my session variable is null and if it is not, then proceed with my C# logic. Is that correct? Will my Session variable ever contain garbage in it, like a corrupted string? Or will I be guaranteed that it is null if not explicitly set.
if(Session["MyVariable"]!=null {
// Do some logic }
var pq = attributes.SingleOrDefault(a => a.AttributeName == PasswordQuestion").AttributeValue;
The above code will throw an error if null. What is the best way to handle this?The below code would work, but I can't help but feel there's a more graceful way?
var pq = (attributes.SingleOrDefault(a => a.AttributeName == "PasswordQuestion") != null) ? attributes.SingleOrDefault(a => a.AttributeName == "PasswordQuestion").AttributeValue : null;
I know for a fact that the SQL statement below returns NULL but my code statement "if (obj != null)" is not working.When I debug it I see a value of {} ... not sure what that is. Here is my code:
[Code]....
So, even if SQL returns NULL, it still validates obj as NOT NULL !
I have Sub that requires EventArgs as below.
Sub Testing(ByVal sender As Object, ByVal e As EventArgs)
If I want to call the Sub from PageLoad event, I wrote like this Testing(nothing,nothing)
Then, in the Sub, I would like to check If Argment is Nothing or not
Dim testID As String
If (CType(sender, LinkButton).CommandArgument) = Nothing
testID=Request.QuerySting("myID")
ELSE
testID=(CType(sender, LinkButton).CommandArgument).ToString
End If
I get Null error at if statement (If (CType(sender, LinkButton).CommandArgument) = Nothing)
I have an aspx page which allows a user to submit modified entries into the database, but when the user clicks Submit to fire the stored procedure I want to first run a check to see if a modified row with the same relationship exists.I am passing the results of the following query:
SELECT SwitchRoom.ModifiedID FROM SwitchRoom WHERE
SwitchRoomID = @ChkSwitchRmID", constring;
into a DataReader to determine if that relationship exists.I need it to determine whether the reader returns NULL to allow the procedure to execute, if it doesn't, then don't allow the user to save the information.I've tried the following:
if (dbreader = NULL)
{
Fire Procedure
}
else
{
"Error Message"
}
and I've even tried passing the reader into a datatable and running it against that without any luck.
How do you check for null with HtmlAgilityPack? I'm getting "Property or indexer 'HtmlAgilityPack.HtmlNode.HasChildNodes' cannot be assigned to -- it is read only" with the following.
if (Node.Element("TD").HasChildNodes = DBNull.Value)
I"m getting "Object reference not set to an instance of an object. " with
if (Node.Element("TD").HasChildNodes)
I want to catch the session if is null how can I do this. My session is:
Session["kullanici_name"].ToString();
if it is null
Response.Redirect("kulanicigiris.aspx");
And I want to make a logout button. If he /she press the button session=null then page load and check if the session null going to home page.
I use the simple code in onunload's body method like this:
<body
onunload="closeIt()"> ... </body>
The closeIt method is call a server method, like this:
function closeIt ()
{
$.ajax({
type: "POST",
url: "mypage.aspx/myFunc",
data: '{}',
contentType: "application/json; charset=utf-8",
dataType: "json",
//async: false,
success: function(response){},
failure: function(response) {
alert(response.d);
}
});
}
I delete a folder in temp directory in myFunc method. The folder's name is the same of value in Session["id"], like this:
string id = Session["id"];
string temp = "~/temp" + id;
temp = Server.MapPath(temp);
DirectoryInfo dr = new DirectoryInfo(temp);
Directory.Delete(dr.FullName);
When the last code( Directory.Delete(dr.FullName) ) is run, the all session in project is changed to null. If i disable the last code( //Directory.Delete(dr.FullName) ) every thing work properly(all session have the value). Why when i enable the last code, all session are null? What's the problem and how can i solve it?
I have a web site using master page and login page. I use the MasterPage to check the availability of a session. I'm coding with VB + MS Access database.I believe something is wrong with my master page and I can't figure it out. In the code behind of the MasterPage, I try to check the user session is available. If so, the user is still logged and get access to all the menu. If no session is available, it means the user is logged out and few menu as shown. Here is the code
[Code]....
Please note that my Login.aspx page is also base on the same MasterPage. On the Login.aspx.vb, if the user credential are correct, I did this:
[Code]....
So my logic is this: when the web site is launched MasterPage + Default.aspx load. So Sesson("MyLink") is empty. If the user's credential are correct, I create the session so the it can be available for MasterPage.My default menu isMenuPublic1, MenuPublic2, MenuPublic3When a user logged in, I add to the MenuPublic some reserved menu like below.MenuPublic1, MenuPublic2, MenuPublic3, Menu_Users1, Menu_Users2, Menu_Users3I'm testing my application on two different web hosting server: aspspider.com and somee.com. In the local, everything works perfectly fine.My problem is that on aspspider.com if a user logged in and then click on any MenuPublic, the application does not let him show information from Menu_Users. It's wrongly sending him to the login.aspx but still show his profil on the masterpage and the "welcome username" with beside the Logout link. It seems like the user is still connected but cannot have access to users pages.On the other server (somee.com), even if the user logged in successfully, I still have "welcome guess" with beside the Login link. I also have the user's profil information with all the links. If a user click on any MenuPublic, he can still see all the Menu_Users. But if he clicks on any Menu_Users, the application redirect him to the login.aspx; but still displaying all the information as if he is logged.The package deployed on both server is the same; except the connection string.FYI, I have Global.asa in the package but I don't use it. The web.config has plenty of stuff that came when I first start the project. The only thing I added is the connection string.
I have the following code
public class ProductDetails
{
private string _productid;
public string ProductID
{
get { return _productid; }
}
private string _description;
public string Description
{
get { return _description; }
}
private string _image;
public string Image
{
get { return _image; }
}
public ProductDetails(string productid, string description, string image)
{
_productid = productid;
_description = description;
_image = image;
}
}
public class DataAccess
{
private static string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
public ProductDetails GetProductDetails()
{
SqlConnection con = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand("ProductDetails", con);
cmd.CommandType = CommandType.StoredProcedure;
string productid = HttpContext.Current.Request.QueryString["productid"];
cmd.Parameters.Add(new SqlParameter("productid", SqlDbType.NVarChar)).Value = productid;
con.Open();
SqlDataReader reader = cmd.ExecuteReader();
reader.Read();
ProductDetails pro = new ProductDetails(
(string)reader["ProductID"], (string)reader["Description"], (string)reader["Image"]);
reader.Close();
return pro;
}
}
protected void PopulateControls()
private DataAccess da = new DataAccess();
{
ProductDetails product = da.GetProductDetails();
if (product.Description == String.Empty)
{
lblDescription.Visible = false;
}
else
{
lblDescription.Text = product.Description;
}
}
In the last piece i want to check if the Description field is null or empty in order to hide the label control but i get an error if i write: if (product.Description == DBNull.Value) and can only use ring.Empty. But i want to check for NULL values as well..
So I took over this project and one page is throwing a lot of errors. I would need to refactor the whole thing but as always time is an issue.
In one case the code check's whether a datareader has any rows and if not go to an error page. However as the code is now the datareader can be null (didn't successfully connect to db) and in those cases I can't use
if (!dr.HasRows)
//
becasuse it obviously gives me 'nullreferenceexception was unhandled by code'. I tried with !dr.Read but same thing.
A part of the code is something like
SqlDataReader dr = null;
try
{
//connect to db etc
dr = DbHelper.GetReader("sp_GetCustomer", param);
}
catch
{
//show an error message
}
// and then:
if (!dr.HasRows)
{
}
How can i check if an output parameter is null before i bind it to a asp literal, and if it is null i want to just make the literal
hname1.Text = cmd.Parameters("@hotel1").Value
hname1.DataBind()
hname2.Text = cmd.Parameters("@hotel2").Value
[code]...
Actually i have a table with 7 columns
1) Title varchar(100)
2)Description varchar(300)
3)ProfilePicture varbinary(max)
4) Image1 varbinary (max)
5)Image2 varbinary(max)
6)Image3 varbinary(max)
7)Image4 varbinary(max)
Image1,2,3,4 are not a mandatory fields so, when i inserted, i check it if it is not there then i insert null value, Now problem is when i retrive them if there is a row contain image1,2 are image content and 3,4 are null values dataset also filling as it is in database but when i checking like
[code]....
it shows error like
Unable to cast object of type 'System.DBNull' to type 'System.Byte[]'.
Inside a function I need to check to see if a variable value is null, how to do this? I implemented the code but its not returning the value I thought it would return.If it's null I want to set the value of the variable, else I want to query the value from a table
[Code]....
Right now I have an error if f.ParentID is null:
DataSet1.TreeItemRow[]
TreeItemRows = (from f
in tidt
where (f.ParentID == TreeItemId)
select f).ToArray();
I must continue if f.ParentID is null, I don't want to include null fileds in the array. What is the right syntax for that is linq sql?
