.NET Tutorials, Forums, Interview Questions And Answers
Welcome :Guest
Sign In
Win Surprise Gifts!!!

Top 5 Contributors of the Month
david stephan
Gaurav Pal
Post New Web Links

is null for label?

Posted By:      Posted Date: October 19, 2010    Points: 0   Category :ASP.Net

hi, i have the error:

System.Web.UI.WebControls.Label' does not contain a definition for 'IsNull' and no extension method 'IsNull' accepting a first argument of type 'System.Web.UI.WebControls.Label' could be found (are you missing a using directive or an assembly reference?)

referring to:

Line 26:     Label3.Text = userProfile.UserName;
Line 27:
Line 28: if (!Label2.IsNull)
Line 29: {
Line 30: Label2.Visible = true;

Can anyone help? thanks!

View Complete Post

More Related Resource Links

NULL label doesn't appear on drop down or multi-select parameter.

Hi, I am using SSRS 2005 SP3. I have the following query that I use for my parameter: SELECT 0 AS c1, 'NOT Specified' AS c2 UNION SELECT 1 AS c1, NULL AS c2 UNION SELECT 2 AS c1, 'Test 1' AS c2 UNION SELECT 3 AS c1, 'Test 2' AS c2 Let's call my parameter prm1. The type of prm1 is string and it has "Allow null value" and "Allow blank value" options ticked. C1 is the value field and C2 is the label field for prm1. When I preview the report, and I didn't see NULL in my drop down list,  but that record has been shown as 1 (which is the value). I am wondering if this is a normal behavior of SSRS? It's not a big deal. I can replace NULL with something else, but I am just curious. Cheers, Uzzie

SSRS 2005 + Null check box + change Label 'NULL'

Hi, My management asked me if I can change the label of NULL check box for report parameters. They said that users may not understand 'NULL' label means. Is it possible to do. When I searched, some said it can be done by creating custom control and registering it in GAC etc. I appreciate your response. Thanks, Spunny

displaying the word label in asp:label if the query is null


how to disabled the word label in my aspx page if my query is null... i dont like to show the word label in my aspx page.

im using c# .net

How to check for null/empty strings on dynamic objects?


What is the proper way to check for null or empty strings on dynamic objects? This is the only solution I've found so far:

if (admin.PasswordHash.GetType() == typeof(DBNull) || admin.PasswordHash == string.Empty)

If the field is null, the object returned is DBNull.Value, but if the field is empty string, it's return as a System.String object. This makes it impossible to do regular "admin.PasswordHash == DBNull.Value" check, as that will fail whenever the field has been set to empty string. Is my example the right (and only) way to go?

Users getting logged out because HttpContext.Current is null


We've  been trying to fix this one for a couple years, and I'm just out of ideas, so any help is really appreciated!

We've got a fairly large, complex web application that uses Forms Authentication to authenticate users.  Throughout the application we store and retrieve information about users in the Session object, and in some cases in cookies.  In a couple places we check for the existence of the context, and if it's null we send the user back to the login page to re-establish the session. 

Just a quick run-down of this web app: C#, .NET 3.5, IIS 6, ASP.NET State Service to manage session

As for the session timer, we use our own home-grown timer, which is basically a client-side timer, which is backed up by a check to the SQL database to see when their last activity was.  This seems to work well for us.  It's not perfect, but it allows us to notify the user before the session times out, and allows us to be certain we're not logging a user out before their 60 minutes of inactivity is up.

What's happening is that certain users are being logged out after just a few minutes.  We've eliminated the timer as a cause and believe what's happening is the HttpContext.Current is null, so the user is logged out.  We do not know why the HttpContext.Current is null, and I underst

Print row count on Label



I have an SP that simply performs a COUNT(*) from a table. I'm am trying to print that number in an ASP Label. It works in Query analyzer but I cant wrap my head around how to display it in a label. Any guidance much appreciated. 

Thank you. 

How to display a count of search results with keywords in a label?


Sorry for a basic post here; I am very new to VB!

I am currently building a search page, which includes a textbox and two drop-down lists, a search button, and a datagrid. If results are found and displayed, I would like a label to display:

(e.g.) "24 results found for 'blue sky clouds' "

...where the integer represents the results count, and the keywords and/or drop-down list selections are included in the string.

If no results are found I would like the label to display:

(e.g.) "No results were found that match your selection. Please try again"

I would also like the label to be invisible until a search occurs.

Thanks in advance!

'element.className' is null or not an object



I just downloaded the project, compiled it and ran it right out of the box and when I put the mouse pointer over or remove the mouse pointer from either MenuItem in the menu demo, I generate this error:

'element.className' is null or not an object

It points to this javascript method:

updateClassName: function(operation, element, name, value) {
        this[operation + 'String'](
                function() {
                    return element.className;
                function(newValue) {
                    element.className = newValue;

Page.FindControl Causing Null Reference Exception


Hi guys,

I developed a page in VWD 2008 and it works perfectly locally, but when I deployed it on the server every Page.FindControl() call is causing the NullReference Exception "Object reference not set to an instance of an object. " Can anyone help me out? Code is below


Mike Marshall

            For i As Integer = 1 To 10
                If (CType(Page.FindControl("last_" & i), TextBox).Text.Length > 0) Or (CType(Page.FindControl("first_" & i), TextBox).Text.Length > 0) Or (CType(Page.FindControl("dob_" & i), TextBox).Text.Length > 0) Then
                    Dim person_entry(7) As String
                    person_entry(0) = info_list.Count - 1
                    person_entry(1) = CType(Page.FindControl("last_" & i), TextBox).Text
                    person_entry(2) = CType(Page.FindControl("first_" & i), TextBox).Text
                    person_entry(3) = CType(Page.FindControl("dob_" & i), TextBox).Text
                    person_entry(4) = CType(Page.FindControl("appear_" & i), TextBox).Text
                    person_entry(5) = CType(Page.FindControl("mental_" & i), TextBox).Text
                    person_entry(6) = CType(Page.FindControl("behave_" & i), TextB

how to assign string value to a label control


When i do the following i am getting object ref not set to instance of an object:

there is value in string variable would like to assign to a label.

lblFilename.Text = strFilename


Thank you very much for the helpful info

linq and max, if return null return error


hi there
i have this query :

var result2 = (from TH in DB.Threshold
                          where TH.ProductSKUID == int.Parse(HID_ProductSKUID.Value)
                          select TH.ThresholdID).Max();

the problem is that if this query does not find any items, return null, so thow exception
how can i do to return 0??

ObjectDataSource CancelSelectOnNullParameter="false" // Select all when select parameter is null or


Hi ! I am using an objectdatasource in my project and I want to select all rows when the selectparameter value is empty ! I did the following but I am failling;
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" DataObjectTypeName="TugberkUgurluCom_TransferModule.TransferPriceDetailsAll" SelectMethod="GetAllDataFromPricesForControl" TypeName="TugberkUgurluCom_TransferModule.TransferPriceDBComponent" UpdateMethod="UpdateTransferPrices">
    <asp:ControlParameter ConvertEmptyStringToNull="true" ControlID="DropDownList1" Name="TpDestID" PropertyName="SelectedValue" Type="

How to deal with NULL values in a SQL table


 Hi all

In order to add/update/delete data from a table I build 2 classes: 1 class containing all the table fields and another class with methods to add/insert/update/delete records. I am learning how to avoid errors when your table must use SQL NULL values. One error is when I call my UPDATE method (see below):

  public void UpdateItem(OcItemConstraintDetails item)
  SqlConnection con = new SqlConnection(connectionString);
  SqlCommand cmd = new SqlCommand("ItemConstraints_Update", con);
  cmd.CommandType = CommandType.StoredProcedure;

  cmd.Parameters.Add(new SqlParameter("@itemConstraintId", SqlDbType.Int, 4));
  cmd.Parameters["@itemConstraintId"].Value = item.ItemConstraintId;

  cmd.Parameters.Add(new SqlParameter("@path", SqlDbType.NVarChar, 150));
  cmd.Parameters["@path"].Value = item.Path;

if you watch the SQL profiler trace you will see that I am passing a value of 'default' ;so that causes me problems.

exec ItemConstraints_Update @itemConstraintId=1,@path=default

With that said, what are the best practices when your SQL table accepts NULL values and when:
- you are passing an empty value to your stored procedure;

How to get a link within a label


<asp:Label ID="UiMatchAll" runat="server" CssClass="sans-serif-small-bold-SHAMU" Text="Match all of the following criteria..." />


I have this label but I want my text to contain a link, the word "all" I want to be a link so that it looks like "Match all of the following criteria..."  you know with the all underlined representing a link.....



error in MicrosoftAjax.js: Cannot read property '_notified' of null


I am cross testing my project with multiple browsers: IE7, Firefox and Chrome.

One one page I have a dynamically built table with two DropDownLists and CascadingDropDown extenders. Maybe the only thing special about the drop down lists is, that I add a "onChange" for the second drop down list in each row which shows or hides the list depending on the value populated from the web services.

All of this works perfectly in IE7 and Firefox, but Chrome does not execute the JavaScript in the onChange attribute and the error console says:

Uncaught TypeError: Cannot read property '_notified' of null

ASP.NetWindows Application  .NET Framework  C#  VB.Net  ADO.Net  
Sql Server  SharePoint  Silverlight  Others  All   

Hall of Fame    Twitter   Terms of Service    Privacy Policy    Contact Us    Archives   Tell A Friend