I have i = double.Parse(TextBox.Text); but when I enter the + symbol, this error appear "System.FormatException: 'Input string was not in a correct format.'"
If I have a string with a valid math expression such as:  String s = "1 + 2 * 7";   Is there a built in library/function in .NET that will parse and evaluate that expression for me and return the result? In this case 15.
Do reactions interrupt their triggers or not? In the Player's Handbook, it is pretty clear that reactions normally interrupt the thing that they are reacting to.    Xanathar's Guide to Everything, however, has explicitly changed all reactions to occurring after their triggers have finished resolving unless the ability specifies otherwise, and is reliant on that implicit assumption for several reaction abilities already.  This leads to contradictory interpretations of reactions that take implicit timing. How should this be resolved?   I'm particularly interested in how to resolve this in Adventurers League games, where players show up with perfectly legal characters reasonably expecting their abilities to work either way on account of owning or not owning XGE. Find $P(12)$ when $P(x)={1\over(x+1)}$, for $x=0,1,2,......11$ let $P(x)$ be a polynomial of degree $11$ such that  $P(x)={1\over(x+1)}$, for $x=0,1,2,......11$  then find value of $P(12)$ If you have the ability to cast a spell without a spell slot, can you cast that spell using a spell slot? A switch that is only ON if the reference voltage is matched -+ 0.1 volts Im a beginnerish will electronic and im looking for a switch that is only ON if the reference voltage is matched -+ 0.25 volts. So if i have a reference of 2.7v to match and i feed the switch a 2.75v the switch would be ON. But if i feed it  2.5v or 2.85v the switch would is OFF.   This might be a simple google search, but i am lacking the correct terminology. How to look up a symbol or identify a letter from a math alphabet or other character? How to remove specific elements in a numpy array How to forward specific log file outside of /var/log with rsyslog to remote server? How can I forward message from a specific log file like /www/myapp/log/test.log with rsyslog client to remote rsyslog server? This log file is outside of the directory /var/log. I have a client that has a Links page in SharePoint 2013. On the page is a column called URL that is set as a hyperlink column, but they want the column to accept pw://example.com/... instead of just ...  Is there a way to change the hyperlink column to allow for this behavior? I considered creating it as a single line of text and then making that text box a hyperlink-enabled box. Is there another native option? If not, which of these would be easiest? I am new to SharePoint so any help would be appreciated! Thanks in advance!   URL    Type the Web address: (Click here to test)  pw://test  Invalid URL: pw://test How should we handle downvote retaliation? I have a situation where I'm trying to figure out what the right thing to do is on SO.    I see a question.  I answer the question.  I see there are a couple other answers.  One answers the question well, though with less explanation than my answer.  The other answer seems both wrong and irrelevant to the question (doesn't answer the question at all).  I comment to that effect.  The "wrong" part is edited out, but the author of the answer doesn't respond to how their answer actually answers the question.  In fact, they seem offended that I don't "get" it.  After giving them several chances to explain how their answer is relevant to the question and seeing their attitude, I decide to downvote their answer as I don't see how it addresses the question at all and the author won't explain.  They retaliate and downvote my answer and admit in their comments that their downvote of my answer has nothing to do with the content of my answer and only because they don't like me disputing their answer.  Did I do the right thing by downvoting their answer?  Do I just have to live with their downvote retaliation?  Anything I should have done differently?  I also have no way of knowing this for sure, but the next question I answered was upvoted, then downvoted so perhaps this same person is stalking my answers and downvoting other answers of mine too with no comment.  As long as this doesn't continue, I'm not losing sleep over a couple downvotes, but I do wonder if I should have done anything differently.  Followup Later After I Posted This Question: After thinking about it for a little while, the person who disagreed with me decided to delete their post.  So, eventually the message did get through to them.  I don't know if they rescinded their downvote or not (or if they even could). How to add a vertical line to a plot What *is* an Artificial Neural Network? Explanation behind Second Derivative of a Parametric Equation Formula Enabling Nvidia driver messes up splash screen Why a line is said to have infinite number of points? Where can I find stock or custom ROMs for my Android device? Customizing citations and the list of publications depending on the author Say I use a bibliography file in my document, relying on Biblatex and Biber for citation management.  Given a citation command such as \cite{A, B, C} (or any other standard Biblatex citation command), I'd like the resulting citations to be typeset differently depending on whether a given field (e.g. the author field) in the corresponding bibliography entry contains a given string (e.g. someone's lastname).   Besides, I'd like to generate two different bibliography sections in the resulting document, depending on the same condition as above.  Typically this would be used to differentiate, both at the citation level in the main text and in the appendix, the publications that I co-authored from others.  EDIT: adding a MWE:  \documentclass{article} \usepackage{filecontents} \usepackage[backend=biber,style = alphabetic]{biblatex} \usepackage[colorlinks=true, breaklinks, allcolors = blue]{hyperref} \DeclareSourcemap{%   \maps[datatype=bibtex]{%     \map{%       \step[fieldsource=author, match=Doe, final]%       \step[fieldset=keywords, fieldvalue=doe]%     }%   }% } \begin{filecontents}{\jobname.bib} @Book{p1,   author =       "A. U. Thor and John Doe",   title =        "A Scientific Article 1",   year =         "1975"   } @Book{p2,   author =       "John Doe",   title =        "A Scientific Article 2",   year =         "1985"   } @Book{p3,   author =       "Joe Bar",   title =        "A Scientific Article 3",   year =         "1995"   } @Book{p4,   author =       "Jane Baz",   title =        "A Scientific Article 4",   year =         "2005"   } \end{filecontents} \addbibresource{\jobname.bib} \begin{document} % Requirement 1: should make citations of Doe bold In \parencite{p4, p1, p2, p3}, ``TD75'' and ``Doe85'' should appear in bold (the semicolon should remain plain).  % Requirement 2: separating bibliographies. IT WORKS. \section{Co-authored Publications} \nocite{*} \printbibliography[keyword=doe,heading=none]  \section{Other Publications} \nocite{*} \printbibliography[notkeyword=doe,heading=none]  \end{document} How do I overload the square-bracket operator in C#? DataGridView, for example, lets you do this:  DataGridView dgv = ...; DataGridViewCell cell = dgv[1,5];   but for the life of me I can't find the documentation on the index/square-bracket operator.  What do they call it?  Where is it implemented?  Can it throw?  How can I do the same thing in my own classes?  ETA: Thanks for all the quick answers.  Briefly: the relevant documentation is under the "Item" property; the way to overload is by declaring a property like public object this[int x, int y]{ get{...}; set{...} }; the indexer for DataGridView does not throw, at least according to the documentation.  It doesn't mention what happens if you supply invalid coordinates.  ETA Again: OK, even though the documentation makes no mention of it (naughty Microsoft!), it turns out that the indexer for DataGridView will in fact throw an ArgumentOutOfRangeException if you supply it with invalid coordinates.  Fair warning. This is a  about DNS server administration.   I have one hundred or so domains. All of these domains need to be configured identically, but it seems like a huge waste of time to have to configure a new zone and/or zonefile for every one of these domains. There has to be a better way to automate this!  I think I'm on to something...if I create a zone called ., or use some other feature in my DNS software to always return a specific IP when an A record is requested, this seems to get me pretty close to my desired end result. My server is responding authoritatively to the requests and it's so much easier to manage!  This was working great until nameserver validation software started checking these domains. I figured out that I can make most of the errors go away by adding NS records, but my software won't let me put more than one SOA record in the same zone file.  How do I work around this multiple SOA record problem? Landscape topography from grayscale image The preimage of a subset If $A\subseteq B$ under what conditions is $f^{-1}(A) \subseteq f^{-1}(B)$, where $f^{-1}$ is the preimage, not  the inverse.