how to clear error in asp.net

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I have designing in my web page The error are occur

'dataType' argument cannot be null.
Parameter name: dataType

code

private DataTable CreateDataTable()
       {
           DataTable dt = new DataTable();
           dt.Columns.Add("Size", System.Type.GetType("System.String"));
           dt.Columns.Add("SizeID", System.Type.GetType("System.Int64"));
  (_Error) dt.Columns.Add("Lamination", System.Type.GetType("System.Strings"));
           dt.Columns.Add("Amount", System.Type.GetType("System.Int64"));
           dt.Columns.Add("Noofcopies", System.Type.GetType("System.Int64"));
           dt.Columns.Add("Total", System.Type.GetType("System.Int64"));
           return dt;
       }

Posted 8-Jun-11 22:59pm

kannan 2

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Sergey Alexandrovich Kryukov · Answer 1 · 2011-06-08T23:09:00

Solution 4

From the first glance: there is not such type System.Strings.

Problem solved.

But now, let's see how did you create this problem and how to avoid it. This is extremely bad coding: System.Type.GetType("System.String"), because you're using immediate string constants for argument. What happens if you mistype anything? Compiler won't help you to detect a bug. Why doing it when a decent method exist? Instead, use:

C#

//for example:
System.Type myType = typeof(System.String);

Problem prevented.
Don't get in trouble!

Good luck,

—SA

Posted 8-Jun-11 23:09pm

Sergey Alexandrovich Kryukov

Comments

RakeshMeena 9-Jun-11 5:15am

I've seen a lot many developers doing this. My 5 for pointing it out.

Sergey Alexandrovich Kryukov 9-Jun-11 5:16am

Thank you, Rakesh. Tell those developers they are creating troubles for no reason.
--SA

DaveAuld 9-Jun-11 5:16am

Ok, so you get my 5, for being too damn smart! :) It's people like you that help the likes of me learn, so i can't complain :)

Sergey Alexandrovich Kryukov 9-Jun-11 5:17am

Thank you very much for your good words, Dave.
--SA

Prerak Patel · Answer 2 · 2011-06-08T23:05:00

Solution 2

Your mistake: System.Type.GetType("System.Strings")

Use System.Type.GetType("System.String")

Posted 8-Jun-11 23:05pm

Prerak Patel

Comments

Manfred Rudolf Bihy 9-Jun-11 5:07am

Correct! 5+

Sergey Alexandrovich Kryukov 9-Jun-11 5:11am

I voted 4 this time. You found a bug but what's a fix? Fixing a typo? Wrong!
Please see my solution.
--SA

DaveAuld · Answer 3 · 2011-06-08T23:05:00

Solution 3

Look at the type specified on the error line, you have Strings instead of String (i.e. extra s)

Posted 8-Jun-11 23:05pm

DaveAuld

Comments

Manfred Rudolf Bihy 9-Jun-11 5:07am

Well, spotted! 5+

Sergey Alexandrovich Kryukov 9-Jun-11 5:12am

Yes, but that's not all.
Please see my solution -- important difference.
--SA

Sergey Alexandrovich Kryukov 9-Jun-11 5:11am

I voted 4 this time. You found a bug but what's a fix? Fixing a typo? Wrong!
Please see my solution.
--SA

Manfred Rudolf Bihy · Answer 4 · 2011-06-08T23:04:00

System.Strings should be System.String. If System.Type.GetType can't resolve the type because it's unknown it will return null thus causing your error.

C#

private DataTable CreateDataTable()
{
    DataTable dt = new DataTable();
    dt.Columns.Add("Size", System.Type.GetType("System.String"));
    dt.Columns.Add("SizeID", System.Type.GetType("System.Int64"));
    dt.Columns.Add("Lamination", System.Type.GetType("System.String")); // Corrected to read System.String
    dt.Columns.Add("Amount", System.Type.GetType("System.Int64"));
    dt.Columns.Add("Noofcopies", System.Type.GetType("System.Int64"));
    dt.Columns.Add("Total", System.Type.GetType("System.Int64"));
    return dt;
}

Cheers!

-MRB

praveenkatkuri · Answer 5 · 2011-06-08T23:58:00

Solution 6

Your mistake: System.Type.GetType("System.Strings")
Use System.Type.GetType("System.String")

Posted 8-Jun-11 23:58pm

praveenkatkuri

Ramalinga Koushik · Answer 6 · 2011-06-08T23:09:00

Solution 5

Use System.String to clear the error in Asp.net.

Posted 8-Jun-11 23:09pm

Ramalinga Koushik

Comments

Sergey Alexandrovich Kryukov 9-Jun-11 5:15am

Ramalinga, sorry, but you did not even explain how. Why answering just for answering? I have to vote 3.
For a correct solution, please see mine.
--SA

how to clear error in asp.net

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