Ok,
I have a string in a sql table like this
hello /r/n this is a test /r/n new line.
When i retrieve this string using c# for a textbox using multiline i expect the escape chars to be newlines.
But they are not and what happens is i get the line exactly as it is above.
It seems that the string returned from the table is taken as literal but i want the newlines!
How do i get this to work?
Thanks in advance..
/ is not the escape character, \ is. What you need is:
hello \r\n this is a test \r\n new line.
Things like "\n" (not "/n" by the way) are escape characters in programming languages, not inherently in text. (In particular, they're programming-language dependent.)
If you want to make
hello\r\nthis is a test\r\nnew line
format as
hello
this is a test
new line
you'll need to do the parsing yourself, replacing "\r" with carriage return, "\n" with newline etc, handling "\" as a literal backslash etc. I've typically found that a simple parser which just remembers whether or not the previous character was a backslash is good enough for most purposes. Something like this:
static string Unescape(string text)
{
StringBuilder builder = new StringBuilder(text.Length);
bool escaping = false;
foreach (char c in text)
{
if (escaping)
{
// We're not handling \uxxxx etc
escaping = false;
switch(c)
{
case 'r': builder.Append('\r'); break;
case 'n': builder.Append('\n'); break;
case 't': builder.Append('\t'); break;
case '\\': builder.Append('\\'); break;
default:
throw new ArgumentException("Unhandled escape: " + c);
}
}
else
{
if (c == '\\')
{
escaping = true;
}
else
{
builder.Append(c);
}
}
}
if (escaping)
{
throw new ArgumentException("Unterminated escape sequence");
}
return builder.ToString();
}
There are more efficient ways of doing it (skipping from backslash to backslash and appending whole substrings of non-escaped text, basically) but this is simple.
I had a similar problem with my SQLite database the other day. Users are able to enter multi-line text into a textbox, and when it's inserted into the database, it goes in like:
"This is \r\n a multiline test"
It was coming out of System.Data.SQLite as:
"This is \\r\\n a multiline test"
I ended up using:
String.Replace("\\r","\r").Replace("\\n","\n")
to replace each of the escaped characters, which formatted the text properly when displayed in either a multi-line textbox or label.
Looks like you need to use System.Web.HttpUtility.HtmlDecode on the string before putting it in the TextBox.
textBox.Value = HttpUtility.HtmlDecode(myString);
I do not see why a Parser is required in this instance, given that the language in question is C# and I assume that the OS is 32-bit Windows which treats \r\n as the NewLine character.
The following simple code (Windows app) works for me:
string s = "hello \r\n this is a test \r\n new line.";
// Set Multiline to True.
textBox1.Multiline = true;
// Expand the height of the textbox to be able to view the full text.
textBox1.Height = 100;
textBox1.Text = s;
The textbox shows text as:
hello
this is a test
new line.
I think the issue here is that the string as seen by the user is
hello \r\n this is a test \r\n new line.
while the C# code sees it as
"hello \\r\\n this is a test \\r\\n new line."
A much simpler solution would be the following
s = Regex.Replace(s, @"\\\\", @"\");
which replaces @"\\" with @"\". Don't be confused by the regex match pattern, the \ has to be escaped in the match but not the replacement.
