C# Discussion Boards - CodeProject

Re: Encrypt bitmap image for C# Windows application

nudma19-Mar-09 7:13

nudma

19-Mar-09 7:13

I tried that but again

Bad Length

error is at:

byte[] encrypted =  rsaCSP.Encrypt(toEncrypt, false);

Please help me out... Frown | :(

Re: Encrypt bitmap image for C# Windows application

Henry Minute19-Mar-09 7:31

Henry Minute

19-Mar-09 7:31

OK.

After a little research. I think the problem might lie in the length of the input.
From a little reading it seems that RSACryptoServiceProvider was designed for encrypting cryptographic keys, it gets a bit upset if you ask it to do too much work. A bit like me.

There is quite a bit on the web about this problem, and I would suggest that you do a little more research. I Googled "RSACryptoServiceProvider Bad Length", and if you do the same, you might find a solution, but I doubt it.

Choose another CryptoServiceProvider, if you are allowed to. I think that will make your life a whole lot easier.

Henry Minute

Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”

Re: Encrypt bitmap image for C# Windows application

nudma24-Mar-09 6:42

nudma

24-Mar-09 6:42

Hi Henry!!
Thanks for your help...I searched that too...None of the article contains image encryption through RSACryptoserviceprovider. other CryptoServiceProviders are used...

String to int

mrithula818-Mar-09 23:47

mrithula8

18-Mar-09 23:47

Hi can i convert a string to integer variable in C#?If so can you please tell me.I have given the port number <port>10000<port> in an xml file .I want to read this number from xml and assign to int variable so that it can be passed to the IPEndPoint() for client/server commnuication.Whatever i read from xml is retrieved as string.I tried with ConvertToInt() but still im not getting.Can you please explain me the reason?

Re: String to int

musefan18-Mar-09 23:50

musefan

18-Mar-09 23:50

int result;

int.TryParse("10000", out result);

Life goes very fast. Tomorrow, today is already yesterday.

Re: String to int

Michael Bookatz19-Mar-09 0:54

Michael Bookatz

19-Mar-09 0:54

what's the difference between the method you've used and

result = int.parse("100000");

Re: String to int

Mohammad Dayyan19-Mar-09 1:03

Mohammad Dayyan

19-Mar-09 1:03

there is no difference

Re: String to int

musefan19-Mar-09 1:08

musefan

19-Mar-09 1:08

The difference is that if you pass a string to int.parse() that is not a valid string (contains noon-numeric characters) it will throw an exception that you will need to manually handle.

If you use my method the error is handled automatically and the result is set to 0, its up to you if you want to handle the error yourself thou, depends how much validation control you need.

if you are expecting the result could sometimes be 0 as a result then you may be best to handle the error yourself. but in the case of a port number you shouldnt need to do this, just check if result is 0 for an error.

Life goes very fast. Tomorrow, today is already yesterday.

Re: String to int

Michael Bookatz19-Mar-09 1:14

Michael Bookatz

19-Mar-09 1:14

Thank you for the reply... next time I convert I'll bare it in mind.

Re: String to int

DaveyM6919-Mar-09 2:09

DaveyM69

19-Mar-09 2:09

musefan wrote:
just check if result is 0 for an error

Better to assign and check the boolean return value of the TryParse method before working with the value. Still preferable to catching an exception!

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Re: String to int

musefan19-Mar-09 2:15

musefan

19-Mar-09 2:15

Ahh yes, i forgot TryParse() returns a bool

Life goes very fast. Tomorrow, today is already yesterday.

Re: String to int

Mirko198019-Mar-09 1:11

Mirko1980

19-Mar-09 1:11

If the input string is not a valid integer, int.Parse throws an exception, while int.TryParse returns false without setting result value.

e.g.

string wrong = "xyz";
result = int.Parse(wrong); // an exception is thrown here

string wrong = "xyz";
int result = -1;
bool success = int.TryParse(wrong, out result); // success is false, while result will still be -1

Re: String to int

Michael Bookatz19-Mar-09 1:16

Michael Bookatz

19-Mar-09 1:16

Thanks for the reply, however according to the above post the result would be set to zero and not stay at -1 or is it only set to zero if there is no valid number in it?

Re: String to int

Mirko198019-Mar-09 1:36

Mirko1980

19-Mar-09 1:36

Yes, I was wrong, int.TryParse puts 0 in the result if the parsing fails.
For some reason, I tought that the resul value was unchanged in case of failure, my bad.

Re: String to int

Michael Bookatz19-Mar-09 2:11

Michael Bookatz

19-Mar-09 2:11

No worries thanks for the clarification

Re: String to int

DaveyM6919-Mar-09 2:11

DaveyM69

19-Mar-09 2:11

hopingToCode wrote:
only set to zero if there is no valid number

... or if the number in the text is zero! Check the return value of the TryParse method to determine if successful.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Re: String to int

DaveyM6919-Mar-09 0:18

DaveyM69

19-Mar-09 0:18

musefan has given you the perfect answer. Just be aware that if the number can't be converted to an int you will get zero.

I have an extension method that I use when working with text/xml etc files to simplify stuff.

public static class ExtensionMethods
{
    /// <summary>
    /// Converts a string to an integer.
    /// </summary>
    /// <param name="value">The string to convert.</param>
    /// <returns>The integer value of the string if valid; otherwise, zero.</returns>
    public static Int32 ToInt32(this string value)
    {
        int result;
        Int32.TryParse(value, out result);
        return result;
    }
}

Now I can can just use something like

int intFromFile = stringFromFile.ToInt32();

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Re: String to int

Greg Chelstowski19-Mar-09 0:57

Greg Chelstowski

19-Mar-09 0:57

If I might...
Is it considered really bad practice to do Convert.ToInt32 ?
I have seen stuff (and well, I have used it, too) like:

string x = "10";
int xInt;
try
{
xInt = Convert.ToInt32(x);
}
catch
{
xInt = 0;
}

Would that not do the same as TryParse?
Or is it an unnecessary way around it, or simply, crap?

var question = (_2b || !(_2b));

Re: String to int

DaveyM6919-Mar-09 2:18

DaveyM69

19-Mar-09 2:18

Not bad practice, possibly a little slower going via the Convert class but I would have to check the implementation to be sure.

The convert class is great for converting from a built in type to another (not just from string), but I would guess the Int32.Parse or Int32.TryParse methods would be perhaps a little more efficient.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Build number control

12Code18-Mar-09 23:25

12Code

18-Mar-09 23:25

How can i automatically increments the build number in an AssemblyInfo.cs?

Any example? using macro or function method?

Kelvin

Re: Build number control

Nagy Vilmos18-Mar-09 23:35

Nagy Vilmos

18-Mar-09 23:35

MS, he say:
The version number has four parts, as follows:

<major version>.<minor version>.<build number>.<revision>

You can specify all the values or you can accept the default build number, revision number, or both by using an asterisk (*). For example, [assembly:AssemblyVersion("2.3.25.1")] indicates 2 as the major version, 3 as the minor version, 25 as the build number, and 1 as the revision number. A version number such as [assembly:AssemblyVersion("1.2.*")] specifies 1 as the major version, 2 as the minor version, and accepts the default build and revision numbers. A version number such as [assembly:AssemblyVersion("1.2.15.*")] specifies 1 as the major version, 2 as the minor version, 15 as the build number, and accepts the default revision number. The default build number increments daily. The default revision number is random.

Panic, Chaos, Destruction.
My work here is done.

Re: Build number control

Simon P Stevens18-Mar-09 23:48

Simon P Stevens

18-Mar-09 23:48

williamnw wrote:
[assembly:AssemblyVersion("1.2.*")]

I've tried this and I've never been able to get it to work. It always just gives me a version of "1.2.*" on the actual file.

Have you got it working williamnw? (Sorry for hijacking your thread 8kelvin)

For 8kelvin: There are two other options:

1) The AssemblyInfo[^] task can be used to auto increment the version number by modifying the assemblyinfo.cs file prior to the build being run. You just add an include statement to your project file.

2) There's a task in the MSBuild Community Tasks[^] project that can be used to generate a version number and write it into a generated assemblyinfo.cs file prior to the build running. Again, it just requires some additions to your csproj file (or msbuild script if you use it)

To be honest I have problems with both methods in my projects. We have large projects containing multiple assemblies and always end up with references screwed up because one of them is trying to reference versions prior to the number increment, or version numbers getting incremented twice or stupid things like that. This is the one area of our system I'm very unhappy with, but I can't find a decent solution.

Simon

Re: Build number control [modified]

12Code19-Mar-09 0:06

12Code

19-Mar-09 0:06