how do i delete characters in a string/text of a textbox? - asp.net

I have an asp.net 4 textbox control that has it's text being dynamically populated by some java script. A Google Maps call to be exact. It's giving me mileage from 1 point to another. When the text displays, it shows " 234 mi" I need to get rid of the "mi" part of this text because the text is being converted to an Int32 Updating a table in my DB.
Basically I can only have an INT. Nothing else in the text box. How do I get rid of the "mi" at the end of the text?
Thanks
C#
EB

On the postback, before you save it you could:
var saveValue = Int32.Parse(tbTarget.Text.Replace("mi", string.Empty).Trim());

If your working with a variable length of chars (say someone enters miles instead) then your must do a foreach against the string (an array of char) and check isnumeric on each char.

A simple String.Substring works also:
String leftPart = TxtMileAge.Text.Substring(0, txt.IndexOf(' '));
int mileAge = int.Parse(leftPart);
This retrieves the part of the String in the range of 0 - indexOfWhiteSpace and converts it to an int
Edit: Since the value can have decimal places (as you've commented), you need to parse it to double, round it and then cast it to int:
var txtEstDistance = new TextBox() { Text = "40.2 mi" };
String leftPart = txtEstDistance.Text.Substring(0, txtEstDistance.Text.IndexOf(' '));
double distanceMiles = double.Parse(leftPart, System.Globalization.CultureInfo.InvariantCulture);
int oDdstanceMiles = (int)Math.Round(distanceMiles, MidpointRounding.AwayFromZero);

Related

How to convert emojis from to unicode in Xamarin.forms?

I have Xamarin.Forms project. I have textbox in that and have a button which get text from textbox and pass it to API to store. Now the point is when user select any emojis from keyboard, I want to get unicode character of the emojis. Currently I am getting emojis it self when I check Text property of it.
I want to get Unicode rather emoji as given in NewTextValue from Text property.
This post is same but I don't understand how the guy has managed. POST
Please suggest.
After some google, I have tried with following.
string res = BitConverter.ToString(Encoding.BigEndianUnicode.GetBytes(str)).Replace("-", "");
This is result res = D83DDE00
I don't know above code is unicode or not.
How can I convert back to original emoji or is there any other way to convert in unicode?
We need to manually convert it back. Insert "-" every two characters:
var convertStr = string.Join("-", Regex.Matches(res, #"..").Cast<Match>().ToList());
String[] tempArr = convertStr.Split('-');
byte[] decBytes = new byte[tempArr.Length];
for (int i = 0; i < tempArr.Length; i++)
{
decBytes[i] = Convert.ToByte(tempArr[i], 16);
}
String str = Encoding.BigEndianUnicode.GetString(decBytes);
Moreover in my test, Encoding.UTF32.GetBytes() may be closer to emoji code. You can test it with \U0001F600, this is a smile image. After converting with utf32, the bytes just change its order.

textbox is empty but still showing the count

I have textbox1 field in asp.net and a text area to show count of records.
I want to count the records split by , in textbox1 but when textbox1 is empty text area is showing 1.
Here is the code.
int contacts = textbox1.Text.Split(',').Count();
textarea.Text = contacts.ToString();
String.Split always returns at least one string, if you pass string.Empty you will get one string which is the input string(so in this case string.Empty).
Documentation:
....
If this instance does not contain any of the characters in separator,
the returned array consists of a single element that contains this instance.
You have to check it, f.e. with string.IsNullOrEmpty(or String.IsNullOrWhiteSpace):
int contacts = 0;
if(!string.IsNullOrEmpty(textbox1.Text))
contacts = textbox1.Text.Split(',').Length;
Try this
int contacts = string.IsNullOrEmpty(string.textbox1.Text)? string.empty: textbox1.Text.Split(',').Count();
textarea.Text = contacts.ToString();
This is because even when textbox1.Text is an empty string, that's still treated as one item. You need to use StringSplitOptions.RemoveEmptyEntries so that empty entries are ignored when producing the result of calling Split:
var contacts = textbox1.Text.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
.Count();
To decompose what you've written into individual statements, what you have is:
var items = textbox1.Text.Split(new char[] { ', ' }, StringSplitOptions.RemoveEmptyEntries);
var countOfItems = itemsFromText.Count();
If you look at items you'll see that it's an array of strings (string[]) which contains one entry for each item in the text from textbox1.Text.
Even if an empty string is passed in (i.e. textbox1 is empty) there's still one string to be returned, hence the fact that your code as written is returning 1, whereas in countOfItems where I've broken the code apart it will have 0 because of the use of StringSplitOptions.RemoveEmptyEntries.
The documentation on msdn of the String.Split overload that takes StringSplitOptions as a parameter has more examples and detail about this.

Textbox dont allows null value in ASP .Net

i have column in database with Int data type, but textbox don't allows null. it gives error "Input string was not in a correct format".
objinsert.VehGrpID = Convert.ToInt32(txtVehGroupID.Text);
Use TryParse instead.
int GrpID = 0;
int.TryParse(txtVehGroupID.Text, out GrpID)
if(GrpID > 0)
objinsert.VehGrpID = GrpID;
You can just special-case out empty values. I am, of course, assuming here that an empty value should map to null.
objinsert.VehGrpID = string.IsNullOrWhiteSpace(txtVehGroupID.Text) ? null : (int?)Convert.ToInt32(txtVehGroupID.Text);
You'll also want to adjust your code to set the textbox's text accordingly.
Your question is also a bit unclear, because you say the textbox won't allow nulls, but you haven't shown us any code that adjusts the textbox text.
You can also use DBNull.Value Field. If a database field has missing data, you can use the DBNull.Value property.
check this link http://msdn.microsoft.com/en-us/library/system.dbnull.value%28v=vs.110%29.aspx
try this
int VehGrpID = Convert.ToInt32(txtVehGroupID.Text);
OR
int VehGrpIDtxtVehGroupID.Text = int.Parse(txtVehGroupID.Text);
The Text property of your textbox is a String type, so you have to perform the conversion in the code.

Formatting asp.net label when the value is sourced from a query string

Afternoon all.
A very simple one for you today from thicky Rich.
I have a label I want to display as a lovely number format i.e. {0:N0}
Now, this label text equates to a query string value.
How do I go about formatting a label's text from a query string value in one fell swoop?
I have tried this
lblTotalPurchQS.Text = String.Format("{0:N0}",Request.QueryString["totalpurchasequantity"].ToString());
but with little success.
Any ideas or pointers?
Don't use ToString on the incoming query string parameter, but convert it to an int first:
lblTotalPurchQS.Text = String.Format("{0:N0}", int.Parse(Request.QueryString["totalpurchasequantity"]));
Note:
The above is not safe code. First, the conversion may fail with a conversion exception. You should also be HTML escaping the output, in case of XSS.
This is better:
int totalPurchaseQuantity;
if(int.TryParse(Request.QueryString["totalpurchasequantity"], out totalPurchaseQuantity))
{
lblTotalPurchQS.Text = Server.HtmlEncode(String.Format("{0:N0}", totalPurchaseQuantity);
}

Why is this looping infinitely?

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.

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