We Keep Coding

How to validate a Text in Asp.net [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I want to put check to validate textbox that input value must not be similar to the values already present in database. Like:
if there is value with text "Hello" in database then user must not be allowed to save value either he writes:
Hello
HELLO
hElLo
HeLLO
Hello etc
I followed this http://www.dotnetperls.com/string-isupper-islower but as i am new to c# so have little confuse that how to match above defined words as all are same words Hello

I typically just convert both values (user input and stored value) to lower case when making the comparison.
Edit: if both values are in .NET, you could use String.Compare(s1, s2, StringComparison.OrdinalIgnoreCase)

Do you need to do this in code? I would suggest that you just make a unique constraint on the column and let the database handle that for you. Depending on the database you are using you may need to do a little additional work to handle the case sensitivity.

How to know the page break in Excel using C# [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I´m using C# to create and format a Excel spreadsheet, so I need to format (merge cells, change the font, etc) until the final of the first page. How can I know the final line of the page in the Excel spreadsheet?

The following code will give you the last row number before every horizontal page break in an Excel worksheet:
foreach (Excel.HPageBreak pageBreak in worksheet.HPageBreaks)
{
int row = pageBreak.Location.Row - 1;
// ...
}

Converting file content to string and store in sharepoint column [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions concerning problems with code you've written must describe the specific problem — and include valid code to reproduce it — in the question itself. See SSCCE.org for guidance.
Closed 9 years ago.
Improve this question
I have a requirement to allow user to upload any file (pdf, doc, ect) to sharepoint and later on download the file as needed. the upload and download tasks are implemented as asp.net web app. Currently, I convert the file content (byte array) to base64 string and store in sharepoint. For download, I get the content from sharepoint and do convert from base64 to string then I write this string to browser. The result did not look like original file. What is wrong?

From your question it sounds like the problem is you are converting the Base64 data to a string. Since Base64 is a representation of binary data using only printable characters it works fine as a string, but interpreting binary data directly as a string can result in data corruption. It's like trying to edit an EXE file using Notepad.
You need to convert the Base64 back to a byte array and write that to the browser.

RSACryptoServiceProvider helper [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I was looking for RSACryptoServiceProvider helper and found two different implementations
1) http://www.cnblogs.com/WYB/archive/2008/06/19/1225704.html
2) https://github.com/robvolk/Helpers.Net/blob/master/Src/Helpers.Net/EncryptionExtensions.cs
both of them working
var encryptedBytes = myBytes.RSAEncrypt(publicKey);
System.Text.Encoding.Unicode.GetString(encryptedBytes);
returns strings like "蹩巷Ӂය馧㾵봽놶徤蕺蓷課Ϝ堲泍썳⁙䃑ക늏...."
myString.EncryptStringUsingXMLFile(publicKey)
returns strings like "AnvFFT6YpoiAyIFwl+tueZq56Zcb0B7WhBEvz5uWl...."
May be some one can explain why first one producing Chinese strings and how to change that?
What approach is better?

To answer your first question. While it may look like it is producing Chinese characters what is actually happening is it is turning a byte array into unicode. In c# typically when you want to store a byte array you convert it to base64 which is what your second example appears to return.
Your first example would become this:
var encryptedBytes = myBytes.RSAEncrypt(publicKey);
Convert.ToBase64String(encryptedBytes) // this line changed
returns strings like "AnvFFT6YKpoiAy...."
As for what is recommended, the most common is to use base64. The reasons people use base64 over unicode or UTF-8 for binary data can be found in these answers:
https://stackoverflow.com/a/201491/701062
MSDN - Convert.ToBase64String(byte[])
http://msdn.microsoft.com/en-us/library/dhx0d524(v=vs.100).aspx
MSDN - Convert.FromBase64String(string) - Useful if you need to convert back into a byte array
http://msdn.microsoft.com/en-us/library/system.convert.frombase64string(v=vs.100).aspx

Denoising a chart (array of points) [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I wanted to ask what do you think would be the best way to denoise an array of coordinate points.
I've got something like on the bottom drawing and need to convert it into what's on the top drawing.
Thanks :)

Median filter
A typical way of doing signal noise removal is a median filter.
If you have a noisy signal f(x), you can get a denoised signal g(x) by the following:
g(x) = medianz in R(x)(f(z))
where R(x) = [x-w/2, x+w/2] and w is some window width.
Example
Wikipedia has a concrete example.
Here's an example of denoising using a median filter. The first image is the source, the second image is the noisy version, the third image is the denoised version, and the fourth image is the difference between the source and the denoised versions. Notice that most of the error is near boundaries, whereas error in regions without sudden jumps is very low.
For a broader look at the topic, look at Noise reduction.