The problem im having grabbing the attribute names out of xml document. Here is the snippet:
<RUNWAY name="02X" length="3507" slope="-0.11" level_off_height="2228">
I have created a loop to display the results. In the snippet above, how do i grab the attributes name(name, length, slope, and level_of_height). I have used reader.name is giving me RUNWAY which is correct as the elements name. I tried getAttribute and it give me all of the values of the attributes, but not there name. Please forgive the (!) as they are open and closed brackets. It would not let me post my question with those in there. Any help would be very much appreciated
If you are using XmlReader try Reading Attributes (from MSDN):
' Display all attributes.
If reader.HasAttributes Then
Console.WriteLine("Attributes of <" + reader.Name + ">")
Dim i As Integer
For i = 0 To (reader.AttributeCount - 1)
Console.WriteLine(" {0}", reader(i))
Next i
' Move the reader back to the element node.
reader.MoveToElement()
End If
or another way:
If reader.HasAttributes Then
Console.WriteLine("Attributes of <" + reader.Name + ">")
While reader.MoveToNextAttribute()
Console.WriteLine(" {0}={1}", reader.Name, reader.Value)
End While
' Move the reader back to the element node.
reader.MoveToElement()
End If
Related
Everytime I add CharW(34) to a string it adds two "" symbols
Example:
text = "Hello," + Char(34) + "World" + Char(34)
Result of text
"Hello,""World"""
How can I just add one " symbol?
e.g Ideal result would be:
"Hello,"World""
I have also tried:
text = "Hello,""World"""
But I still get the double " Symbols
Furthermore. Adding a CharW(39), which is a ' symbol only produces one?
e.g
text = "Hello," + Char(39) + "World" + Char(39)
Result
"Hello,'World'"
Why is this only behaving abnormally for double quotes? and how can I add just ONE rather than two?
Assuming you meant the old Chr function rather than Char (which is a type).It does not add two quotation mark characters. It only adds one. If you output the string to the screen or a file, you would see that it only adds one. The Visual Studio debugger, however, displays the VB-string-literal representation of the value rather than the raw string value itself. Since the way to escape a double-quote character in a string is to put two in a row, that's the way it displays it. For instance, your code:
text = "Hello," + Chr(34) + "World" + Chr(34)
Can also be written more simply as:
text = "Hello,""World"""
So, the debugger is just displaying it in that VB syntax, just as in C#, the debugger would display the value as "Hello, \"World\"".
The text doesn't really have double quotes in it. The debugger is quoting the text so that it appears as it would in your source code. If you were to do this same thing in C#, embedded new lines are displayed using it's source code formatting.
Instead of using the debugger's output, you can add a statement in your source to display the value in the debug window.
Diagnostics.Debug.WriteLine(text)
This should only show the single set of quotes.
Well it's Very eazy
just use this : ControlChars.Quote
"Hello, " & ControlChars.Quote & "World" & ControlChars.Quote
I am having the following issue:
I am using an application that allows users to concatenate text to build a URL that passes parameters to an ASP page via GET method, i.e. something like:
http://myhostname/process.asp?param1=value1¶m2=value2
Problem is value1 and value2 can contain the ampersand symbol, which is not interpreted as a text character.
The most popular solution to this issue is to encode the URL, which is not an option for me because I cannot modify the program that builds the URL. I can modify the process.asp page, but not the program that concatenates the text fields and builds the URL.
Things I've tried to search for are:
How to encode a URL using javascript directly in the browser
How to change IIS default behaviour when reading an &
Alternative ways to pass parameters, i.e. something like passing them as a single string of characters separated with pipes
Hope you can give me some guidance.
You can read the entire query string and parse it yourself, like this:
q = Request.QueryString
a = Split(q, "=")
i = 1
For Each s In a
If i mod 2 = 0 Then
If InStr(s, "&") <> InStrRev(s, "&") Then
Response.Write "Value: " & Left(s, InStrRev(s, "&") - 1) & "<br/>"
hidingParam = Right(s, Len(s) - InStrRev(s, "&"))
Response.Write "PAramName: " & hidingParam & "<br/>"
i = i + 1
Else
Response.Write "Value: " & s & "<br/>"
End If
Else
Response.Write "PAramName: " & s & "<br/>"
End If
i = i + 1
Next
Result:
URL: ...?Q=abc&def&P=123 produces
PAramName: Q Value: abc&def PAramName: P Value: 123
Note that this is less than robust. I am only illustrating my idea. I didn't test with no &.
It also doens't handle multiple "=" characters (if that's a possiblity as well).
If there are 2 (or more) ampersands in-between the equals, then only the last one is a parameter separator. So, using your URL above, and assuming that value1 = "abc&def", and value2 = "123", then the URL will look like:
http://myhostname/process.asp?param1=abc&def¶m2=123
Notice there's 2 ampersands in-between the 2 equals. The last one will be your parameter separator, the rest are part of the value. And any ampersands after the last equals are also part of the value.
You'll have to dissect the incoming URL and apply the appropriate logic.
I have a string that at any point may or may not contain one or more / characters. I'd like to be able to create a new string based on this string. The new string would include every character after the very last / in the original string.
Sounds like you're wanting the file name from a URL. In any case, it's the same function. The key is using the InStrRev function to find the first / char, but starting from the right. Here's the function:
Function GetFilename(URL)
Dim I
I = InStrRev(URL, "/")
If I > 0 Then
GetFilename = Mid(URL, I + 1)
Else
GetFilename = URL
End If
End Function
Split it up into parts and get the last part:
a = split("my/string/thing", "/")
wscript.echo a(ubound(a))
note: Not safe when the string is empty.
Now it seems like a really simple question and I may just be being thick, but what I'm trying to achieve is basically print an array to screen in the following format:
Item 1, Item 2, Item 3, Item 4
Although I say to screen, as that was the best way I could describe it, I'm actually writing it to the page inside some Javascript.
The way I'm currently going about writing it out is as follows:
for each b in theDates
Response.Write("'" + b.CallDate + "',")
next
But obviously that returns a string of Item 1, Item 2, Item 3, Item 4,.
Is there a simple way of getting rid of the last comma or am I going about this completely wrong?
You could use String.Join method. Not sure about VB but something like that:
Response.Write(String.Join(", ", theDates.Select(Function(n) "'" & n.CallDate & "'").ToArray()))
Try String.Join (documentation). My VB is rusty, but hopefully you can read this C#:
var datesInQuotes = theDates.Select(date => "'" + date.CallDate + "'");
Response.Write(String.Join(", ", datesInQuotes));
As others have said, String.Join is what you want in this case.
More generically: you've got to either detect when you're at the the last element and not append a comma, or detect when you're at the first element and not prepend a comma.
Typically it's easier to detect when you're at the first, so:
dim firstDone as bool = false
for each b in theDates
if firstDone then Response.Write (",")
Response.Write("'" + b.CallDate + "'")
firstDone = true
next
(Excuse my rusty vb)
There's no need to String.join this.
st="'"
for each b in theDates
Response.Write(st + b.CallDate + "'")
st=", '"
next
No, you aren't wrong - totally.
Loop through theDates and put the data into a string.
After you are done looping, remove the last comma:
myString.Remove(myString.Length - 1, 1);
Response.Write(myString)
A side note: You really shouldn't output to the screen with Response.Write. You should set the text of a server control as your output. A label is perfectly fine. You will notice that your text won't appear where you think it will if you don't.
You could write the comma in front of each item except the first one.
I would recommend to do just as you were doing, and then use the Response.Remove(s.Length-1, 1)
In C#:
for (int i = 0; i < theDates.Length; i++)
{
if (i > 0)
{
Response.Write(",");
}
Response.Write(theDates[i]);
}
all too complicated. Keep it simple
dim st as string ="'"
for each b in theDates
Response.Write(st + b.CallDate + "'")
st=", '"
next
response.write (st.TrimEnd(New Char() {" ", ","})
So I just got my site kicked off the server today and I think this function is the culprit. Can anyone tell me what the problem is? I can't seem to figure it out:
Public Function CleanText(ByVal str As String) As String
'removes HTML tags and other characters that title tags and descriptions don't like
If Not String.IsNullOrEmpty(str) Then
'mini db of extended tags to get rid of
Dim indexChars() As String = {"<a", "<img", "<input type=""hidden"" name=""tax""", "<input type=""hidden"" name=""handling""", "<span", "<p", "<ul", "<div", "<embed", "<object", "<param"}
For i As Integer = 0 To indexChars.GetUpperBound(0) 'loop through indexchars array
Dim indexOfInput As Integer = 0
Do 'get rid of links
indexOfInput = str.IndexOf(indexChars(i)) 'find instance of indexChar
If indexOfInput <> -1 Then
Dim indexNextLeftBracket As Integer = str.IndexOf("<", indexOfInput) + 1
Dim indexRightBracket As Integer = str.IndexOf(">", indexOfInput) + 1
'check to make sure a right bracket hasn't been left off a tag
If indexNextLeftBracket > indexRightBracket Then 'normal case
str = str.Remove(indexOfInput, indexRightBracket - indexOfInput)
Else
'add the right bracket right before the next left bracket, just remove everything
'in the bad tag
str = str.Insert(indexNextLeftBracket - 1, ">")
indexRightBracket = str.IndexOf(">", indexOfInput) + 1
str = str.Remove(indexOfInput, indexRightBracket - indexOfInput)
End If
End If
Loop Until indexOfInput = -1
Next
End If
Return str
End Function
Wouldn't something like this be simpler? (OK, I know it's not identical to posted code):
public string StripHTMLTags(string text)
{
return Regex.Replace(text, #"<(.|\n)*?>", string.Empty);
}
(Conversion to VB.NET should be trivial!)
Note: if you are running this often, there are two performance improvements you can make to the Regex.
One is to use a pre-compiled expression which requires re-writing slightly.
The second is to use a non-capturing form of the regular expression; .NET regular expressions implement the (?:) syntax, which allows for grouping to be done without incurring the performance penalty of captured text being remembered as a backreference. Using this syntax, the above regular expression could be changed to:
#"<(?:.|\n)*?>"
This line is also wrong:
Dim indexNextLeftBracket As Integer = str.IndexOf("<", indexOfInput) + 1
It's guaranteed to always set indexNextLeftBracket equal to indexOfInput, because at this point the character at the position referred to by indexOfInput is already always a '<'. Do this instead:
Dim indexNextLeftBracket As Integer = str.IndexOf("<", indexOfInput+1) + 1
And also add a clause to the if statement to make sure your string is long enough for that expression.
Finally, as others have said this code will be a beast to maintain, if you can get it working at all. Best to look for another solution, like a regex or even just replacing all '<' with <.
In addition to other good answers, you might read up a little on loop invariants a little bit. The pulling out and putting back stuff to the string you check to terminate your loop should set off all manner of alarm bells. :)
Just a guess, but is this like the culprit?
indexOfInput = str.IndexOf(indexChars(i)) 'find instance of indexChar
Per the Microsoft docs, Return Value -
The index position of value if that string is found, or -1 if it is not. If value is Empty, the return value is 0.
So perhaps indexOfInput is being set to 0?
What happens if your code tries to clean the string <a?
As I read it, it finds the indexChar at position 0, but then indexNextLeftBracket and indexRightBracket both equal 0, you fall into the else condition, and then you insert a ">" at position -1, which will presumably insert at the beginning, giving you the string ><a. The new indexRightBracket then becomes 0, so you delete from position 0 for 0 characters, leaving you with ><a. Then the code finds the <a in the code again, and you're off to the races with an infinite memory-consuming loop.
Even if I'm wrong, you need to get yourself some unit tests to reassure yourself that these edge cases work properly. That should also help you find the actual looping code if I'm off-base.
Generally speaking though, even if you fix this particular bug, it's never going to be very robust. Parsing HTML is hard, and HTML blacklists are always going to have holes. For instance, if I really want to get a <input type="hidden" name="tax" tag in, I'll just write it as <input name="tax" type="hidden" and your code will ignore it. Your better bet is to get an actual HTML parser involved, and to only allow the (very small) subset of tags that you actually want. Or even better, use some other form of markup, and strip all HTML tags (again using a real HTML parser of some description).
I'd have to run it through a real compiler but the mindpiler tells me that the str = str.Remove(indexOfInput, indexRightBracket - indexOfInput) line is re-generating an invalid tag such that when you loop through again it finds the same mistake "fixes" it, tries again, finds the mistake "fixes" it, etc.
FWIW heres a snippet of code that removes unwanted HTML tags from a string (It's in C# but the concept translates)
public static string RemoveTags( string html, params string[] allowList )
{
if( html == null ) return null;
Regex regex = new Regex( #"(?<Tag><(?<TagName>[a-z/]+)\S*?[^<]*?>)",
RegexOptions.Compiled |
RegexOptions.IgnoreCase |
RegexOptions.Multiline );
return regex.Replace(
html,
new MatchEvaluator(
new TagMatchEvaluator( allowList ).Replace ) );
}
MatchEvaluator class
private class TagMatchEvaluator
{
private readonly ArrayList _allowed = null;
public TagMatchEvaluator( string[] allowList )
{
_allowed = new ArrayList( allowList );
}
public string Replace( Match match )
{
if( _allowed.Contains( match.Groups[ "TagName" ].Value ) )
return match.Value;
return "";
}
}
That doesn't seem to work for a simplistic <a<a<a case, or even <a>Test</a>. Did you test this at all?
Personally, I hate string parsing like this - so I'm not going to even try figuring out where your error is. It'd require a debugger, and more headache than I'm willing to put in.