We Keep Coding

String comparison fails even when visually checked

I added a function to my application recently that reads a date from a downloaded file and finds the difference in days between current date and the date from the file. When done, it is displayed in a label in one of my forums.
There is an exception: if the string in the file equals "Lifetime", it should not process it as a date and follow alternate logic. But when I try to check if the string is "Lifetime", it does not return true, even if the string = "Lifetime".
EDIT: I fixed the FormatException with help from Nisarg. Now, my labels aren't changing to the values. This is the problem.
EDIT2: I feel stupid. I found out that I was initiating Main twice in one function, then using main1 to switch between forms and main to set the labels.
This is why the labels weren't working right. Thanks Nisarg and all other contributors.
Code example:
string subScript = File.ReadAllText(Path.GetTempPath() + txtUsername.Text + ".txt");
Main main = new Main();
double dSubLeft;
main.dateLabel.Text = subScript;
if (subScript == "Lifetime") // it bypasses this, apparently blank
{
main.daysLeftLabel.Text = "Expires: Never";
}
if (subScript != "Lifetime") //Goes here and throws error saying subScript is not valid DateTime
{
dSubLeft = Math.Round(Convert.ToDouble(Convert.ToString(((Convert.ToDateTime(subScript)) - DateTime.Now).TotalDays)));
string sSubLeft = Convert.ToString(dSubLeft);
main.daysLeftLabel.Text = "Expires: " + sSubLeft + " Days";
}

While using files you often get trailing blank spaces or newline characters. Try trimming the string before comparing it to Lifetime:
subScript = subScript.Trim().Trim(Environment.NewLine.ToCharArray());
Another (less likely) problem could be with the comparison itself. In C# the comparison in case-sensitive. So if you're comparing lifetime with Lifetime they are considered unequal. You should rather use case-insensitive comparison:
if(string.Equals(subScript, "Lifetime", StringComparer.OrdinalIgnoreCase))
OR
if(subScript.ToLower() == "lifetime")
You could also check if the subScript you are getting from the file is a valid date or not using DateTime.TryParse.
string subScript = File.ReadAllText(Path.GetTempPath() + txtUsername.Text + ".txt");
Main main = new Main();
double dSubLeft;
main.dateLabel.Text = subScript;
DateTime subScriptDate;
if(!DateTime.TryParse(subScript, out subScriptDate))
{
main.daysLeftLabel.Text = "Expires: Never";
}
else //Goes here and throws error saying subScript is not valid DateTime
{
dSubLeft = Math.Round(Convert.ToDouble(Convert.ToString((subScriptDate - DateTime.Now).TotalDays)));
string sSubLeft = Convert.ToString(dSubLeft);
main.daysLeftLabel.Text = "Expires: " + sSubLeft + " Days";
}

I think it is because main is the starting point of a program in C#, make another methodname if you don´t want it to reset things from where the program is supposed to start from
That is my guess only, make a breakpoint in the beginning of your code and check through what info you get from each row in the code

Almost certainly, the actual content of the string is not actually the string "Lifetime". Probably because of white-space on either side. Try trimming.
Relevant edit:
if (subscript.Trim() == "Lifetime")
{
main.daysLeftLabel.Text = "Expires: Never";
}
else // don't retest for the opposite condition
{
...
As you can see, this thing is awfully fragile, because the string could still be many things that aren't a valid DateTime. Smells like homework, but there you go...

i think you should use
if(string.Equals(subScript, "Lifetime", StringComparer.OrdinalIgnoreCase))
{
//statement
}
else
{
//statement
}

How to insert apostrophe in the middle of string using string.Insert c#

I have a bunch of string which i loop through . I want to insert an apostrophe when ever an apostrophe in any string that has apostrophe. I simply do something like below.
string strStatus = "l'oreal";
index = strStatus.IndexOf("'");
strStatus.Insert(index, " ' ");
I want to have output like l''oreal. Yet this fails. I tried using escape patter
strStatus.Insert(index, " \' ");
All to no avail. Please how do i achieve this? Any suggestion/help is highly appreciated.

Strings are immutable. Insert returns a new string with the 2 apostrophes, it doesn't modify strStatus in any way. Your code simply discards the result of Insert.
You should try:
string strStatus = "l'oreal";
index = strStatus.IndexOf("'");
string newStatus=strStatus.Insert(index, "'");

Strings are immutable in .NET (and Java), which means Insert does not modify strStatus, instead it will return a new instance which has the modification you're after.
Do this:
String status = "L'Oreal";
status = status.Insert( status.IndexOf('\''), "'" );

Strings are immutable in C#, so all it's methods do not modify the string itself - they return modified copy. This should work:
strStatus = strStatus.Insert(index, " ' ");

How to replace double quotes with / in a string with some other value in C#

I have image tag in my html like img src="/images/image.jpg".
I want it like src="mydomain.com/images/image.jpg"
So I want to replace all src="/ to src="mydomain.com/.
I tried this
string repto = "src=\"/" + strLink.HRef + "/";
strEncode.Replace("src=\"/", repto);
strEncode contains my html.
I tried many ways but nothing is working. Please help, if any body has any idea about this.
Thanks

string foo = #"src=\"/images/image.jpg\"";
string bar = foo.Replace("src=\"", "src=\"mydomain.com");

Maybe
html_string.Replace("src=\"/images", "src=\"mydomain.com/images");
?

String#Replace does not change the value of strEncode, in fact it returns a new string with the encoded value.
So this may help you out:
strEncode = strEncode.Replace("src=\"/", repto);

Exception while converting String to Double C#

I take data from four different pages and different domains.
1- .com
2- .co.uk
3- .ca
4- .co.jp
For all of the above i take number from Html and Convert them to Double using line:
string lowestSellerPrice = (Convert.ToDouble(fbalPrice) +
Convert.ToDouble(fbalsPrice)).ToString();
This works perfectly fine for the first 3 domains but for .co.jp even though there is always a number in fbalPrice and fbalsPrice it is always giving exception :
Input string was not in a correct format
Any suggestion as i have been struggling with this for too long now no result i also tried the try parse solution but no luck.
UPDATE:
See this:

I solved it like this :
The string were like " 1234" and " 111" and i then did Replace(" ",""); . And only number lift this however did not work so i did this:
if (fbalPrice.Contains(" "))
{
fbalPrice = fbalPrice.Remove(0, fbalPrice.IndexOf(" ") + 1).Replace(",","").Trim();
}
if(fbalsPrice.Contains(" "))
{
fbalsPrice = fbalsPrice.Remove(0, fbalsPrice.IndexOf(" ") + 1).Replace(",", "").Trim();
}
And then added them and it worked.

The spaces inside the URL

I have created the yahoo weather API app using ASP.Net MVC 3 and when I tried to insert the postcode to the text field to find the correct xml, I wanted to leave gap for the standard UK postcode. Can you please help me to do that. The following code's model.PostCode represents the PostCode variable which has declared as string in model. This code is in the controller file.
private Boolean LookupWeather(ref RssModels model)
{
string WoeidUrl = "http://where.yahooapis.com/v1/places.q('" +
model.PostCode +
"')?appid=EzZDnOXV34EzJpQ8mX8mc62cYk1Gu21DzUhsLr.4nQ2qz.xffZah.RNq8lObxA--";
XDocument getWoeid = XDocument.Load(WoeidUrl);
try
{
model.Woied = (int)(from place in getWoeid.Descendants("place")
select place.Element("woeid")).FirstOrDefault();
return true;
}
catch
{
return false;
}
If you can please help me to get the URL like follows.
http://where.yahooapis.com/v1/places.q('mk10%202hn')?appid=EzZDnOXV34EzJpQ8mX8mc62cYk1Gu21DzUhsLr.4nQ2qz.xffZah.RNq8lObxA--
Thank you in advance.

Use UrlEncode
string WoeidUrl = "http://where.yahooapis.com/v1/places.q('"
+ UrlEncode(postCode)
+ "')?appid=EzZDnOXV34EzJpQ8mX8mc62cYk1Gu21DzUhsLr.4nQ2qz.xffZah.RNq8lObxA--";

All the browser is doing for that is replacing the space with %20, you can replicate this just by using Replace, try:
string postCode = model.PostCode.Replace(" ", "%20");
Then use it in your code above like so:
string WoeidUrl = "http://where.yahooapis.com/v1/places.q('"
+ postCode
+ "')?appid=EzZDnOXV34EzJpQ8mX8mc62cYk1Gu21DzUhsLr.4nQ2qz.xffZah.RNq8lObxA--";