Pass C ASP NET array to Javascript array

Question

Does anyone know how to pass a C  ASP NET array to a JavaScript array  Sample code will also be nice   Sorry if I was vague earlier guys  The question is actually quite simple  Let s say for simplicity that in my aspx cs file I declare   int    numbers   new int 5     Now I want to pass numbers to the client side and use the data in the array within JavaScript   How would I do this

User · Answer

Prepare an array  in my case it is 2d array               prepare a 2d array in c          ArrayList header   new ArrayList    Task Name    Hours            ArrayList data1   new ArrayList   Work   2           ArrayList data2   new ArrayList    Eat   2            ArrayList data3   new ArrayList    Sleep   2            ArrayList data   new ArrayList  header  data1  data2  data3              convert it in json         string dataStr   JsonConvert SerializeObject data  Formatting None              store it in viewdata  viewbag         ViewBag Data   new HtmlString dataStr        Parse it in the view     lt script gt          var data   JSON parse   ViewBag Data        console log data    lt  script gt    In your case you can directly use variable name instead of ViewBag Data

User · Answer

serialize it with System Web Script Serialization JavaScriptSerializer class and assign to javascript var  dummy sample    lt   var serializer   new System Web Script Serialization JavaScriptSerializer      gt  var jsVariable    lt    serializer Serialize array    gt

User · Answer

You can use ClientScript RegisterStartUpScript to inject javascript into the page on Page Load   Here s a link to MSDN reference  http   msdn microsoft com en-us library asz8zsxy aspx  Here s the code in Page Load     List lt string gt  tempString   new List lt string gt       tempString Add  Hello      tempString Add  World       StringBuilder sb   new StringBuilder      sb Append   lt script gt       sb Append  var testArray   new Array       foreach string str in tempString          sb Append  testArray push      str                 sb Append   lt  script gt        ClientScript RegisterStartupScript this GetType     TestArrayScript   sb ToString       Notes  Use StringBuilder to build the script string as it will probably be long   And here s the Javascript that checks for the injected array  testArray  before you can  work with it   if  testArray         do something with testArray     There s 2 problems here    Some consider this intrusive for C  to inject Javascript We ll have to declare the array at a global context   If you can t live with that  another way would be to have the C  code save the Array into View State  then have the JavaScript use PageMethods  or web services  to call back to the server to get that View State object as an array   But I think that may be overkill for something like this

User · Answer

This is to supplement zerkms s answer   To pass data across language barriers  you would need a way to represent the data as a string by serializing the data  One of the serialization methods for JavaScript is JSON  In zerkms s example  the code would be placed inside of an aspx page  To combine his example and yours together on one aspx page  you would have    lt       int   numbers   new int 5          Fill up numbers         var serializer   new System Web Script Serialization JavaScriptSerializer      gt    somewhere later on the aspx page   lt script type  text javascript  gt      var jsVariable    lt    serializer Serialize numbers    gt    lt  script gt    This answer though  assumes that you are generating JavaScript from the initial page load  As per the comments in your post  this could have been done via AJAX  In that case  you would have the server respond with the result of the serialization and then deserialize it in JavaScript using your favorite framework   Note  Also do not mark this as an answer since I wanted the syntax highlighting to make another answer more clear

User · Answer

Simple  The array of integers is quite simple to pass  However this solution works for more complex data as well  In your model   public int   Numbers   gt  new int 5     In your view   numbers     new HtmlString JsonSerializer Serialize Model Numbers      Optional  A tip for passing strings  You may want JSON encoder to not escape some symbols in your strings  In this example I want raw unescaped cyrillic letters  In your view   strings      new HtmlString      JsonSerializer Serialize Model Strings  new JsonSerializerOptions               Encoder   JavaScriptEncoder Create              UnicodeRanges BasicLatin              UnicodeRanges Cyrillic

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For array of objects   var array  JSON parse   Newtonsoft Json JsonConvert SerializeObject numbers   replace   amp quot  g            For array of int    var array  JSON parse   Newtonsoft Json JsonConvert SerializeObject numbers

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In the page file    lt script type  text javascript  gt      var a   eval    lt    string Join       numbers    gt       lt  script gt    while in code behind   public int   numbers   WhatEverGetTheArray

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I came up with this similar situation and I resolved it quiet easily Here is what I did  Assuming you already have the value in array at your aspx cs page   1 Put a hidden field in your aspx page and us the hidden field ID to store the array value    HiddenField2 Value   string Join      myarray     2 Now that the hidden field has the value stored  just separated by commas  Use this hidden field in JavaScript like this  Simply create an array in JavaScript and then store the value in that array by removing the commas   var hiddenfield2   new Array    hiddenfield2 document getElementById   lt   HiddenField2 ClientID  gt    value split         This should solve your problem

User · Answer

Here is another alternative solution  You can use ClientScriptManager Page ClientScript RegisterArrayDeclaration  Here is an example for chart data   var page   HttpContext Current CurrentHandler as Page    data     Date UTC 2018  9  29  0  3   parseFloat 21 84              Date UTC 2018  9  29  0  13   parseFloat 21 84              Date UTC 2018  9  29  0  23   parseFloat 21 83              Date UTC 2018  9  29  0  33   parseFloat 21 83     page ClientScript RegisterArrayDeclaration  chartdata0    data     This code creates an array on the client side  var chartdata0   new Array  Date UTC 2018  9  29  0  3   parseFloat 21 84                  Date UTC 2018  9  29  0  13   parseFloat 21 84                  Date UTC 2018  9  29  0  23   parseFloat 21 83                  Date UTC 2018  9  29  0  33   parseFloat 21 83       See the following article  https   docs microsoft com en-us dotnet api system web ui clientscriptmanager registerarraydeclaration view netframework-4 8  This solution has an issue with bigger arrays on chrome 64 browser including  Version 78 0 3904 70  Official Build   64-bit    You may get  Uncaught RangeError  Maximum call stack size exceeded   However it is working with IE11  Microsoft Edge  and FireFox

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