CODEWITHSUNDEEP
c#substring
TeethPain
TeethPain

Reputation: 23

c# Substring doesn't find string

I have this paragraph inside my lotHtmlOriginal.Text

waters71 </strong></p>
<p><strong>websitesss.com/sblogin/login.shtml/</strong><br />
<strong>1234213:123123</strong><br />
<strong>213123:12312</strong><br />
<strong>4213:196028</strong><br />
<strong>32131:43423</strong><br />
<strong>4444444:96980507</strong></p>
<p><strong>htt

I issue is that when I make the second part of substring </p>, the code fails because substring is not able to find it, but when I change it to certain things, it works.

It does not work when I change it too...

This is my code

String St = lotHTMLOriginal.Text; ;
String firstPart = "blogin/login.shtml/</strong>";
String lastPart = "</p>";
int pFrom = St.IndexOf(firstPart) + firstPart.Length;
int pTo = St.IndexOf(lastPart);

String result = St.Substring(pFrom, pTo - pFrom);
lotHTML.Text = result;

And just in case it's not clear, I'm trying to get everything between blogin/login.shtml/</strong> and </p>

Upvotes: 2

Views: 390

Answers (4)

Michael
Michael

Reputation: 566

This code will find the first "</p>" after the beginning of the firstPart.

String lastPart = "</p>";
int pFrom = St.IndexOf(firstPart) + firstPart.Length;
int pTo = 0;
while(pTo - pFrom < 0)
{
    pTo = St.IndexOf(lastPart);
}

Upvotes: 0

Hossein Narimani Rad
Hossein Narimani Rad

Reputation: 32511

Using int pTo = St.IndexOf(lastPart); you will get the index of the first </p>, but you are looking for the last one so I think you should use 

int pTo = St.LastIndexOf(lastPart);

OUTPUT:

<br /> <strong>1234213:123123</strong><br /> <strong>213123:12312</strong><br /> <strong>4213:196028</strong><br /> <strong>32131:43423</strong><br /> <strong>4444444:96980507</strong>

Upvotes: 0

Glenn Ferrie
Glenn Ferrie

Reputation: 10408

I believe this will fix the bug in your code. I've added a new variable to the mix. Let me know if this makes sense / helps. 

    String St = lotHTMLOriginal.Text; ;
    String firstPart = "blogin/login.shtml/</strong>";
    String lastPart = "</p>";
    int pFrom = St.IndexOf(firstPart) + firstPart.Length;

    // these three lines changed
    string St_temp = St.Substring(pFrom);
    int pTo = St_temp.IndexOf(lastPart);
    String result = St.Substring(pFrom, pTo);

    lotHTML.Text = result;

What I ultimately did was to trim the characters before firstPart in St to simplify the code somewhat. It limits the arithmetic you need to do to get the result you are looking for.

// this is the result
<br />
<strong>1234213:123123</strong><br />
<strong>213123:12312</strong><br />
<strong>4213:196028</strong><br />
<strong>32131:43423</strong><br />
<strong>4444444:96980507</strong>

Upvotes: 0

Alexei Levenkov
Alexei Levenkov

Reputation: 100630

It looks like you want to find particular string starting from previously found position like string.IndexOf:

int pTo = St.IndexOf(lastPart, pFrom);

Side note: if you need a lot of HTML processing it may be easier to use HTML parser (like HtmlAgilityPack) instead of using string matching or regular expressions, but for simple one-off code substring is ok.

Upvotes: 2

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