Re: How to get last day of specific date - C# Discussion Boards

Re: Issue with Land Registry Service reference.cs

24-Sep-18 4:08

Do us all a favour and don't post your whole app - do you really think we want to wade through that pile of code trying to find the relevant bits?

Edit your question and cut it down to just the relevant code fragments - and then explain exactly where the problem occurs.

But in this case, we can't help you: we can't run your code in isolation, and it needs to be run under the debugger to find out what exactly is going on.

This is one of the most common problems we get asked, and it's also the one we are least equipped to answer, but you are most equipped to answer yourself.

Let me just explain what the error means: You have tried to use a variable, property, or a method return value but it contains null - which means that there is no instance of a class in the variable.
It's a bit like a pocket: you have a pocket in your shirt, which you use to hold a pen. If you reach into the pocket and find there isn't a pen there, you can't sign your name on a piece of paper - and you will get very funny looks if you try! The empty pocket is giving you a null value (no pen here!) so you can't do anything that you would normally do once you retrieved your pen. Why is it empty? That's the question - it may be that you forgot to pick up your pen when you left the house this morning, or possibly you left the pen in the pocket of yesterdays shirt when you took it off last night.

We can't tell, because we weren't there, and even more importantly, we can't even see your shirt, much less what is in the pocket!

Back to computers, and you have done the same thing, somehow - and we can't see your code, much less run it and find out what contains null when it shouldn't.
But you can - and Visual Studio will help you here. Run your program in the debugger and when it fails, VS will show you the line it found the problem on. You can then start looking at the various parts of it to see what value is null and start looking back through your code to find out why. So put a breakpoint at the beginning of the method containing the error line, and run your program from the start again. This time, VS will stop before the error, and let you examine what is going on by stepping through the code looking at your values.

But we can't do that - we don't have your code, we don't know how to use it if we did have it, we don't have your data. So try it - and see how much information you can find out!

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Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Richard Deeming24-Sep-18 7:56

Richard Deeming

24-Sep-18 7:56

Quote:

//THIS SECTION IS CAUSING ME AN ERROR
request.Product.Contact[1] = new Q1ContactType();
//request.Product.Contact = new Q1ContactType[1];
request.Product.Contact[0].Name = new Q3TextType();
request.Product.Contact[0].Name.Value = "Allen Jones";

request.Product.Contact[0].Communication = new Q1CommunicationType();
request.Product.Contact[0].Communication.Telephone.Value = "01925 938640";
//TO HERE

You're trying to store an element in the array before you've initialized the array. The request.Product.Contact array is null, so if you try to store anything in it, you'll get a NullReferenceException.

The code to initialize the array is on the following line, but you've commented it out.

You're also trying to store an item at index 1, and then modifying the item at index 0. Array indices are zero-based, and your commented-out line is creating an array of length 1, so the only valid index will be 0.

request.Product.Contact = new Q1ContactType[1];
request.Product.Contact[0] = new Q1ContactType();
request.Product.Contact[0].Name = new Q3TextType();
request.Product.Contact[0].Name.Value = "Allen Jones";
request.Product.Contact[0].Communication = new Q1CommunicationType();
request.Product.Contact[0].Communication.Telephone.Value = "01925 938640";

If you're using a recent version of Visual Studio, you can simplify this code by using an initializer[^]:

request.Product.Contact = new[]
{
    new Q1ContactType
    {
        Name = new Q3TextType
        {
            Value = "Allen Jones"
        },
        Communication = new Q1CommunicationType
        {
            Value = "01925 938640"
        }
    }
};

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Issue with Land Registry Service reference.cs

glennPattonWork325-Sep-18 0:52

glennPattonWork3

25-Sep-18 0:52

I though the comment this code is generated by a tool was humorous...

How to get last day of specific date

thepast23-Sep-18 18:11

thepast

23-Sep-18 18:11

I have textbox for inserting date called startdate

i want when user insert date get last day of month in another textbox

forexample startdate: 23/09/2018 "my format is dd/mm/yyyy"

lastdate: 30/09/20

Mycroft Holmes23-Sep-18 20:32

Mycroft Holmes

23-Sep-18 20:32

Have some google foo Google Search[^]

You should learn to do some basic research, it is MUCH quicker.

Never underestimate the power of human stupidity
RAH

Maciej Los23-Sep-18 21:17

Maciej Los

23-Sep-18 21:17

It's quite easy. See:

//we need this to properly convert string into date
System.Globalization.CultureInfo ci = new System.Globalization.CultureInfo("en-US");
//initial date
DateTime dt1 = DateTime.ParseExact("23/09/2018", "dd/MM/yyyy", ci);
//last day of month on specific date
//create new date:
//- add 1 month
//- subtract 1 day
//DateTime dt2 = new DateTime(dt1.Year, dt1.Month+1,1).AddDays(-1);  //bug for december!
DateTime dt2 = new DateTime(dt1.Year, dt1.Month,1).AddMonths(1).AddDays(-1);  //correct one
//display result
Console.WriteLine("{0} => {1}", dt1.ToString("yyyy-MM-dd"), dt2.ToString("yyyy-MM-dd"));
//prints: 2018-09-23 => 2018-09-30

For further details, please see:
DateTime Constructor (System) | Microsoft Docs
How to: convert strings to DateTime | Microsoft Docs

Good luck!

[EDIT]
Please, read OriginalGriff's comment to my answer. In my code is one bug, which you have to handle.
Thanks, OG!

modified 24-Sep-18 4:06am.

OriginalGriff23-Sep-18 21:38

23-Sep-18 21:38

Um...

DateTime dt2 = new DateTime(dt1.Year, dt1.Month+1,1).AddDays(-1);

Did you test that in December? Laugh | :laugh:

Sent from my Amstrad PC 1640
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Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Maciej Los23-Sep-18 22:02

Maciej Los

23-Sep-18 22:02

Good point!

No. Should i?

This part belongs to OP Wink | ;)

[EDIT]
Corrected!
Thanks, OG!

OriginalGriff23-Sep-18 22:26

23-Sep-18 22:26

You're welcome!

Sent from my Amstrad PC 1640
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OriginalGriff23-Sep-18 21:38

23-Sep-18 21:38

Marciej has the right idea, but his method has a problem: it will fail in December, because it tries to create a date in the 13th month of the year.

Have a look at this: DateTime Extensions to Make Some Simple Tasks a Little More Readable[^] - it includes a "Last day of month" function.

Sent from my Amstrad PC 1640
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Richard MacCutchan23-Sep-18 21:54

Richard MacCutchan

23-Sep-18 21:54

thepast wrote:
I have textbox for inserting date called startdate

Using a DateTimePicker Class (System.Windows.Forms) | Microsoft Docs[^] would probably be a better choice.

Stackoverflow

Thomas Kiær23-Sep-18 0:28

Thomas Kiær

23-Sep-18 0:28

Absolut Beginner Smile | :)

can someone explain why i get stackoverflow on this code and how to avoid this ?
Stackoverflow error
After adding this lines to my code i get the stack overflow
static void Udskriv2() {
Console.WriteLine("Start Udskriv 2");
/Udskriv1();
Console.WriteLine("Slut Udskriv 2");

using System;
using System.Collections.Generic;
using System.Text;

namespace Metodekald_H4
{
class Program
{

static void Main(string[] args) {
Console.WriteLine("Start Main");
Udskriv1();
Console.WriteLine("Slut Main");
}
static void Udskriv1() {
Console.WriteLine("Start Udskriv 1");
Udskriv2();
Console.WriteLine("Slut Udskriv 1");
}
static void Udskriv2() {
Console.WriteLine("Start Udskriv 2");
/Udskriv1();
Console.WriteLine("Slut Udskriv 2");
}

static void Udskriv3() {
Console.WriteLine("Start Udskriv 3");
Console.WriteLine("Slut Udskriv 3");
}
}
}

OriginalGriff23-Sep-18 1:13

23-Sep-18 1:13

Because Udskriv1 calls Udskriv2, and Udskriv2 calls Udskriv1

That's called recursion, and it means that because every time a method gets called it ends up being called again before it exits - and because each call needs space on some memory called "the stack" to hold the address it has to go back to when it returns the stack fills up very quickly and you get an error because it has nowhere else it can put addresses.

In this case, it's "indirect recursion" because an intermediate method is involved, but exactly teh same thing happens, just slightly quicker.

Sent from my Amstrad PC 1640
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Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Thomas Kiær23-Sep-18 5:45

Thomas Kiær

23-Sep-18 5:45

Thanks, now i see whats going on.
I have to find a solution to avoid this error, could it be to make a little pause in the code to let the code be finish before it starts again ?
in the school assignment i have on this Smile | :)

i have to find a solution´S ! on how to deal with this.

OriginalGriff23-Sep-18 6:04

23-Sep-18 6:04

No, a pause won't make any difference.

This is going to be difficult to explain without being able to tell when your eyes glaze over, but I'll try.

Suppose you have a stack of coins and a piece of paper. Each time you turn the paper over, you do exactly what it says.
So you turn the paper and it says:

1) Put a coin on the stack.
2) Turn over the paper.

So you do.
The stack grows one bigger, and you turn the paper. This time it says:

1) Put a coin on the stack.
2) Turn over the paper.

So you do.
The stack grows one bigger, and you turn the paper. You know what it says, because you are back where you started!
Each time you turn the paper, the stack of coins gets bigger, and bigger.
At some point, it reaches the ceiling, and you can't add another - but you try to force a coin on, and the whole pile falls to the ground with a crash!

That's what happens with unbounded recursive methods - you keep on calling it, and the stack gets bigger, and bigger until it runs out of space and your application crashes.
Adding a delay doesn't "fix the problem", it just means it takes longer in real-world time to get there, just as it does with the pile of coins. Even if you change one side of the paper to read

1) Put a coin on the stack.
2) Wait 30 seconds.
3) Turn over the paper.

The same problem will happen, the stack will still collapse, but it's happen later on in the day.

The way to fix this is: either get rid of the recursion, or add a boundary condition which lets you out of the method without the recursive call. There really is no other solution!

Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!

Thomas Kiær23-Sep-18 6:14

Thomas Kiær

23-Sep-18 6:14

Wery good expl. !!!

For a minute ago, i talked with another student, he was at the same course last year!
He had in his soulution written that a programmer should not write more code to solve problem as this.
Just remove the code causing this !

Thanks again !

/Thomas

OriginalGriff23-Sep-18 6:27

C# Post files through rest api error

23-Sep-18 6:27

You're welcome!

Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Pradeep Kumar21-Sep-18 13:07

Pradeep Kumar

21-Sep-18 13:07

Hi all i have been trying to post files for a third party tool through rest api with MultipartFormDataContent. Even though i am writing files to MultipartFordatacontent in byte arry i am receiving error saying "400 bad request no filedata section found in multipart post request".

Request:

Method: POST, RequestUri: 'url', Version: 1.1, Content: System.Net.Http.MultipartFormDataContent, Headers:
{

Content-Type: multipart/form-data; boundary="4c10d3d0-f2ac-467e-9b46-3ca172eb646d"
Content-Length: 185
}
--c4757eb4-aefd-450a-a5cc-e879ac7f37ce
Content-Disposition: form-data; name=filedata; filename=pp.txt
Content-Type: text/plain

test file
--c4757eb4-aefd-450a-a5cc-e879ac7f37ce--

Response:
StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
x-transaction-id: 99999_fileuploaddownload_staging_1537571048380:f4e44b3ca701:28:jm91oq79:10113
vary: accept-encoding
Connection: keep-alive
Cache-Control: no-cache
Date: Fri, 21 Sep 2018 23:04:08 GMT
Content-Length: 104
Content-Type: application/json; charset=utf-8
}
{"statusCode":400,"error":"Bad Request","message":"No filedata section found in multipart POST request"}

Re: C# Post files through rest api error

Richard MacCutchan21-Sep-18 21:37

Richard MacCutchan

21-Sep-18 21:37

This is a web development issue, nothing to do with C#.

store image in DB by Parameters.AddWithValue

Member 1352250120-Sep-18 17:01

Member 13522501

20-Sep-18 17:01

hello

i stored image in sql server DB by follow command:

command.Parameters.Add("@attach", SqlDbType.VarBinary).Value = bytFile;

but now i want to do it by

Parameters.AddWithValue

command.Parameters.AddWithValue("@attach", bytFile);

but it dont work .

thanks

Re: store image in DB by Parameters.AddWithValue

OriginalGriff20-Sep-18 21:23