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Server Error in '/' Application.
Object reference not set to an instance of an object.
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 reference not set to an instance of an object.
Source Error:
Line 18: protected void Page_Load(object sender, EventArgs e)
Line 19: {
Line 20: if (Request.QueryString["studentName"].ToString().Trim() == "") lblStudentName.Text = "No Record Found"; else lblStudentName.Text = Request.QueryString["Name"].ToString().Trim();
Line 21: if (Request.QueryString["studentCode"].ToString().Trim() == "") lblStudentCode.Text = "No Record Found"; else lblStudentCode.Text = Request.QueryString["Code"].ToString().Trim();
Line 22: }
Source File: D:\sanjib\niose\noise\noise\noise\recordSaved.aspx.cs Line: 20
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
noise.recordSaved.Page_Load(Object sender, EventArgs e) in D:\sanjib\niose\noise\noise\noise\recordSaved.aspx.cs:20
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
System.Web.UI.Control.OnLoad(EventArgs e) +91
System.Web.UI.Control.LoadRecursive() +74
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2207
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Can you please let me know the url. I think problem is in your querystring parameters.
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Delete your other post there is no need for it. Click the Delete button at the bottom.
The reason you are getting a null reference is because you are trying to ToString where one of your references is not present. This is the thing that's causing the problem. What you need to do is actually test the result from the QueryString before you attempt to do anything with it. You could use something like this:
lblStudentName.Text = GetResultFromQueryString("studentName");
private string GetResultFromQueryString(string queryString)
{
string returnValue = "No record found";
object result = Request.QueryString(queryString);
if (result != null && !string.IsNullOrWhiteSpace(result.ToString())
{
returnValue = result.ToString();
}
return returnValue;
}
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Did you not notice that the second folder is spelt differently?
D:\sanjib\niose\noise\noise\noise\recordSaved.aspx.cs Line: 20
"It's true that hard work never killed anyone. But I figure, why take the chance." - Ronald Reagan
That's what machines are for.
Got a problem?
Sleep on it.
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I missed that in all the noise.
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The multiple posts are quite noisy too. 
"It's true that hard work never killed anyone. But I figure, why take the chance." - Ronald Reagan
That's what machines are for.
Got a problem?
Sleep on it.
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i got a table which contains columns starttime and endtime ,and i want to show data in a gridview ,but how can i show the datetime of now compared with the two ,then shows "expired, progressing,not started"
do in the sql? or create a function in .cs?
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My sql solution - not tested. It can still be done in .cs
I will create a function
Create FUNCTION [dbo].[fn_GetStatus]
(
@StartDate Datetime,
@EndDate Datetime
)
RETURNS NVARCHAR(50)
BEGIN
DECLARE @Status NVARCHAR(50)
IF @StartDate < getdate()
BEGIN
SET @Status = 'not started'
END
IF (@StartDate >= getdate() AND @EndDate <= getdate())
BEGIN
SET @Status = 'progressing'
END
IF (@EndDate > getdate())
BEGIN
SET @Status = 'expired'
END
RETURN @Status
END
Then call
SELECT starttime, endtime, dbo.fn_GetStatus(starttime, endtime) AS Statuses from TableName
I remain joe!
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All,
I'm trying to replicate a design of a GUI which has numerous circles scattered across the form to represent the equivalent of an LED status light.
I'm a total noob at C# 2005, but my million dollar question is how can I do this?
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Stuck At Zero wrote: ... million dollar question ...
For a million dollars, there are lots of us here who will do it for you! 
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Start here[^].
Use the best guess
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I'm actually trying to draw permanent circles onto the Form view of the app I'm trying to create to emulate LED status lights.
Is there nothing on the toolbox that I can use to draw circles directly onto the form view?
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Not that I'm aware of, but you could possibly adapt one of the existing tools, or create a custom one of your own. Google for "custom tools" to find some samples and tutorials.
Use the best guess
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I guess my only options may be to see if I can investigate if I can place 40+ buttons onto the form that I can disable but have visible and see if I can make them circular buttons with the ability for me to change the color of the button.
My other way I suppose would be to draw a circle on something like MS Paint and somehow save it with a transparent background. 50+ pictures on a form. The idea would be to either forcibly change the color of the circle on the picture or to use a different picture of the circle of a different color when an event happens. that I can simply change the color of the circle in the picture as needed (or have varying pictures of the same circle).
I actually thought this was going to be rather easy, but it seems making simple shapes on the GUI is not as easy as I had thought for C#.
Am I better off doing this on Visual C++ or Visual Basic?
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Sounds like you're using Windows Forms. If you were to use WPF (Windows Presentation Foundation), then drawing circles and flipping their color would be trivial.
Do you have to use C# 2005? Why don't you move to 2010 or 2012 (even 2008)? You're simply making things harder for yourself with "older" technology.
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I am using C# 2005 because the workgroup I'm in at work uses C# 2005. I would love to use "newer" technology, but the decision is above my paygrade.
I'm not sure what forms I'm using, other than it's what pops up when I try to make a GUI. Is WPF something that came out in a later version?
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Whether you use "Windows Forms" or "WPF" is usually determined when you create a new Visual Studio project: i.e. choosing Console; Windows Forms; WPF; etc. when you create a new project.
WPF has been around for a while, but since I have only been using it from 2008 on, I don't know how 2005 supports it.
Anyway, if you're limited to 2005, create a new project in VS, and if you have the option to create a WPF project, then you're good to go (unless "the powers that be" insist you use only Windows Forms).
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I'm a total newbie when it comes to C#, so I've been trying to wing it with online tutorials on making GUI apps.
Powers that be don't really care HOW I do it. They just want to see a notional version of what they had envisioned.
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Gerry Schmitz wrote: You're simply making things harder for yourself with "older" technology.
Not true, there is nothing in this question that cannot be solved quite easily in VS 2005.
Use the best guess
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True. I should have said "generally"; or "moving forward".
I assumed that at some point, he would be doing something other than "drawing circles".
But I could be wrong.
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I don't know how much this software will morph over time, but the only other special thing I will need to look into is a "console" window on one of the tabs of my GUI to take manual commands as things are running.
Outside of that, my best guess is that the "drawing circles" is the only quirky feature I need to have for this GUI that isn't obvious on the standard C# toolbox.
Time will prove me wrong.
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Stuck At Zero wrote: Am I better off doing this on Visual C++ or Visual Basic?
Only if you have more experience with either of those languages, although the issue is exactly the same whether you use VB.NET or C#. My original suggestion to use the graphics class is still your best option.
Use the best guess
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Why is that "the best option"? I see no reason why it is better than say WPF. Or flipping picture images as the OP is thinking of.
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Gerry Schmitz wrote: why it is better than say WPF.
In the original question the OP states: "I'm a total noob at C# 2005", which suggests that WPF would be an even bigger mountain to climb.
Use the best guess
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You assume too much. If the OP was prepared to use WPF, I would have posted a solution that any "noob" would have understood.
Any solution (in this case) that is at least object-oriented is superior to one that simply "draws".
The OP is creating a UI (not some scribbles); and creating "leds" implies managing "state" (i.e. on/off); image controls (the OP's thinking), "shapes", etc. are a lot more useful in this case than simply "drawing" (as you are suggesting).
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