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Object reference not set to an instance of an object EROR OCCUR in this code;;;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
public partial class Default3 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (Session["ss"] == null)
{
DataTable ord = new DataTable("Table");
DataColumn c = new DataColumn();
c.ColumnName = "ordbookid";
c.DataType = Type.GetType("System.Int32");
ord.Columns.Add(c);
ord.Columns.Add(new DataColumn("ordbooktit", Type.GetType("System.String")));
ord.Columns.Add(new DataColumn("ordbookaut", Type.GetType("System.String")));
ord.Columns.Add(new DataColumn("ordbookpub", Type.GetType("System.String")));
ord.Columns.Add(new DataColumn("ordbookpri", Type.GetType("System.Int32")));
ord.Columns.Add(new DataColumn("ordbookqty", Type.GetType("System.Int32")));
ord.Columns.Add(new DataColumn("ordbookamt", Type.GetType("System.Int32")));
ord.Columns["ordbookamt"].Expression = "ordbookpri * ordbookqty";
Session["ss"] = ord;
}
if (Page.IsPostBack == false)
{
SqlDataAdapter adp = new SqlDataAdapter("select * from tb_book where bookid=101", ConfigurationManager.ConnectionStrings["cnn"].ConnectionString);
DataSet ds = new DataSet();
adp.Fill(ds);
DataRowView r = ds.Tables[0].DefaultView[0];
DataTable tb = (DataTable)(Session["ss"]);
DataRow r1 = tb.NewRow();
r1[0] = Convert.ToInt32(r["bookid"]);
r1[1] = r["booktit"].ToString();
r1[2] = r["bookaut"].ToString();
r1[3] = r["bookpub"].ToString();
r1[4] = Convert.ToInt32(r["bookpri"]);
r1[5] = 1;
tb.Rows.Add(r1);
GridView1.DataSource = tb;
GridView1.DataBind();
Label1.Text = tb.Compute("Sum(ordbookamt)", "").ToString();
}
}
}
manish soni
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It could be anywhere in there. There will be a stack trace that shows the line the error occurs on.
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Would you mind specifying on what line the error is thrown?? If not, nobody is going to help you.
The problem is simple really. You're assuming an object came back from either a method call or from some collection. You failed to check to see if the returned object is null before attempting to use it. Basically, you assumed the object would be there, and it's not.
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hit a break point in starting of the code, and step over your code one by one, and see which line is throwing exception. and let me know, so that if anything needs to be correct in it.
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Why are you replying to me? The OP now doesn't get an email saying you replied to him. Now it goes to me only
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if (Page.IsPostBack == false)
{
SqlDataAdapter adp = new SqlDataAdapter("select * from tb_book where bookid=101", ConfigurationManager.ConnectionStrings["cnn"].ConnectionString);
DataSet ds = new DataSet();
adp.Fill(ds);
if (ds.Tables[0].DefaultView.Count > 0)
{
DataRowView r = ds.Tables[0].DefaultView[0];
if (r != null)
{
DataTable tb = (DataTable)(Session["ss"]);
DataRow r1 = tb.NewRow();
r1[0] = Convert.ToInt32(r["bookid"]);
r1[1] = r["booktit"].ToString();
r1[2] = r["bookaut"].ToString();
r1[3] = r["bookpub"].ToString();
r1[4] = Convert.ToInt32(r["bookpri"]);
r1[5] = 1;
tb.Rows.Add(r1);
GridView1.DataSource = tb;
GridView1.DataBind();
Label1.Text = tb.Compute("Sum(ordbookamt)", "").ToString();
}
}
}
Sankarsan Parida
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I need Javascript for the above question.... Please send it as soon as possible...
Thanks...
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1. You haven't actually asked a question.
2. We don't do your work for you.
3. This is the .NET forum, not a JavaScript forum.
4. People on this site are volunteers. They work to their timetable, not yours.
5. We don't do your work for you.
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vasuarya wrote: Please send it as soon as possible...
Please forward $1,000,000 to me and I can assure you that I will make this my top priority.
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Any thoughts, though Math and Forms.Application class have all static methods Math class is static while Application is declared as sealed?
I can see that methods in Math class are kind of independent from each other, any other reason you know?
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Mirani Ajay wrote: Any thoughts, though Math and Forms.Application class have all static methods Math class is static while Application is declared as sealed?
You only need one math-class, and having it static makes it faster by eliminating the lookup for the correct object.
Now, the "static" keyword is not there to prevent inheritance; it's there to make sure that there's only one instance of the class (a singleton). The sealed-keyword is there to prevent inheritance.
Application is a special object, containing MarshallByRefObject's - I guess that's the reason why it's not simply a static class.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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How about so you can use them without declaring an instance of the class??
Seems a little obvious to me....
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Dave Kreskowiak wrote: How about so you can use them without declaring an instance of the class?? I'd say that's an too easy answer; only the method needs to be static to get that particular behaviour. The class doesn't need be static nor sealed. Or, in other words, item C already does what you say, without A or B being considered.
static class A
{
public static void FooBar() { }
}
sealed class B
{
public static void FooBar() { }
}
class C
{
public static void FooBar() { }
}
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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Yep, but then again, the question isn't real specific either.
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In .NET 1.0 / 1.1, both the System.Math [^] and System.Windows.Forms.Application [^] classes were sealed with a private constructor.
When static classes were introduced in .NET 2.0, the Math class was updated to take advantage of this new construct, but it looks like the System.Windows.Forms.Application wasn't.
Looking at the source[^], the class doesn't have any instance members, and is never instantiated, so it would have made sense to change it to a static class. However, this change wouldn't make any significant difference, so it's unlikely that it will ever be changed.
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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Mirani Ajay wrote: s Math class is static while Application is declared as sealed? ...Any thoughts,
Microsoft programmers are human just like the rest of us and their implementations are thus subject to the same irregularities that any other programmer might create.
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Hi Friends!I want to make Vb.net application with romanies to Nepali Unicode.(When I type roman text in vb.net control(text box),there should change text into Nepali unicode). Please help me.
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You will need to find or write a program that will translate between the two.
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Is the translitaration of Nepali defined well enough? At least such that the Nepali version can be exactly deduced from the romanized version?
By the way, I'd suggest to process the romanized input not after each keystroke, rather after some "phrase", e.g. after spaces, commas, or on the Leave event of the textbox: Indian alphabets are syllable-centric, with the vocals being written before/after/on top/below/around the consonant (I don't know for Nepali, but that's an Indian alphabet too, isn't it?).
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yes, Nepali is like indian. Please help me. I need romanized input to nepali after space.
Bishnu
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Steps
1. Determine which Unicode character set you are using. Call this U1.
2. Determine what character set will be used in the text box. Call this L1.
3. Determine the span of characters in L1 which must be mapped to U1.
4. Find all of the characters in U1 that correspond to those found in 3.
5. Determine HOW you will store the data from U1. You CANNOT use a string.
6. Create a map of the data from 4 to 5.
7. Implement 6 storing the data as specified in 5.
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I created one windows service and i need to set specific time i.e at 9 AM daily once in windows service.
How to achieve this. If anybody knows please reply me.
thanks in advance.
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I have several classes that wrap native API functions. In those classes I have declared private P/Invoke methods to carry out the class' purpose. My question is a style question from FXCop telling me that I should move those private P/Invoke methods to a NativeMethods class and thus make them available to the entire assembly. One of these messages is
Quote: CA1060 Move P/Invokes to NativeMethods class Because it is a P/Invoke method, 'OSInterface.iniWrapper.GetPrivateProfileSection(ByRef String, Byte(), Integer, ByRef String)' should be defined in a class named NativeMethods, SafeNativeMethods, or UnsafeNativeMethods.
My question is what is considered correct? I consider this to be erroneous because following this advise breaks OO design.
Mike Ober
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