Input string was not in a correct format

Question

I am working on a project in which I have a form through which I can edit a question available in a list view  Whenever I select a row from the list view and click on the  modify  button  the text boxes above the list view load the question and its options  This means that when I select a row in the list view and click on the  modify  button  the question loads itself into the text boxes  I edit the question there and click on  save  to save changes  but I am not able to access the data in the text boxes  It says   Input string was not in a correct format      My code of the form frmFormWizard s  edit  button is given below   frmFormWizard cs Code   using System  using System Collections Generic  using System ComponentModel  using System Data  using System Drawing  using System Linq  using System Text  using System Windows Forms  using System Data Sql  using System Data SqlClient   namespace SurveyBuilder       public partial class frmFormWizard   Form               int intPanelNumber   1          Boolean blnCancel   false            int intFlag   1           public frmFormWizard                         InitializeComponent                                    private void btnEditTwoOrMoreOptions Click object sender  EventArgs e                        int QuestionID                         string sql               QuestionID   Convert ToInt32 lvTwoOrMoreOptions SelectedItems 0  Text ToString                                   SqlConnection cn   new SqlConnection                    SqlCommand rs   new SqlCommand                    SqlDataReader sdr   null                  clsConnection clsCon   new clsConnection                     clsCon fnc ConnectToDB ref cn                    sql                       sql     SELECT   FROM SurveyQuestionLog WHERE SurveyQuestionLog QuestionLogID      QuestionID                        sql     SELECT   FROM SurveyQuestionLog                    rs Connection   cn                  rs CommandText   sql                  sdr   rs ExecuteReader                     while  sdr Read                                          txtTwoOrMoreQuestions Text    string sdr  Question                        txtOption1 Text    string sdr  Choice1                                                               sdr Close                    rs   null                  cn Close                              Whenever I try to compile the code it says    Input string was not in a correct format     and this error is shown on the following line    QuestionID   Convert ToInt32 lvTwoOrMoreOptions SelectedItems 0  Text ToString       Please let me know what I am doing wrong

User · Answer

Problems  There are some possible cases why the error occurs    Because textBox1 Text contains only number  but the number is too big too small Because textBox1 Text contains       a  non-number  except space in the beginning end  - in the beginning  and or b  thousand separators in the applied culture for your code without specifying NumberStyles AllowThousands or you specify NumberStyles AllowThousands but put wrong thousand separator in the culture and or  c  decimal separator  which should not exist in int parsing       NOT OK Examples   Case 1  a   Int32 Parse  5000000000      5 billions  too large b   Int32 Parse  -5000000000      -5 billions  too small   The limit for int  32-bit integer  is only from -2 147 483 648 to 2 147 483 647   Case 2 a   a   Int32 Parse  a189      having a  a   Int32 Parse  1-89      having - but not in the beginning a   Int32 Parse  18 9      having space  but not in the beginning or end   Case 2 b   NumberStyles styles   NumberStyles AllowThousands  a   Int32 Parse  1 189      not OK  no NumberStyles AllowThousands b   Int32 Parse  1 189   styles  new CultureInfo  fr-FR       not OK  having NumberStyles AllowThousands but the culture specified use different thousand separator   Case 2 c   NumberStyles styles   NumberStyles AllowDecimalPoint  a   Int32 Parse  1 189   styles     wrong  int parse cannot parse decimal point at all      Seemingly NOT OK  but actually OK Examples   Case 2 a  OK  a   Int32 Parse  -189      having - but in the beginning b   Int32 Parse   189       having space  but in the beginning or end   Case 2 b  OK  NumberStyles styles   NumberStyles AllowThousands  a   Int32 Parse  1 189   styles     ok  having NumberStyles AllowThousands in the correct culture b   Int32 Parse  1 189   styles  new CultureInfo  fr-FR       ok  having NumberStyles AllowThousands and correct thousand separator is used for  fr-FR  culture     Solutions  In all cases  please check the value of textBox1 Text with your Visual Studio debugger and make sure that it has purely-acceptable numerical format for int range  Something like this   1234   Also  you may consider of    using TryParse instead of Parse to ensure that the non-parsed number does not cause you exception problem  check the result of TryParse and handle it if not true  int val  bool result   int TryParse textbox1 Text  out val   if   result      return    something has gone wrong   OK  continue using val

User · Answer

Please change your code like below     int QuestionID     bool IsIntValue   Int32 TryParse  YOUR-VARIABLE   out QuestionID      if  IsIntValue               YOUR CODE HERE         Hope i will be help

User · Answer

it was my problem too    in my case i changed the PERSIAN number to LATIN number and it worked  AND also trime your string before converting   PersianCalendar pc   new PersianCalendar    char   seperator         string   date   txtSaleDate Text Split seperator   int a   Convert ToInt32 Persia Number ConvertToLatin date 0   Trim

User · Answer

It looks that whatever that text is containing some characters which cannot be converted to integer like space  letters  special characters etc  Check what is coming through dropdown as below  lvTwoOrMoreOptions SelectedItems 0  Text ToString      and see if that is the case

User · Answer

The error means that the string you re trying to parse an integer from doesn t actually contain a valid integer   It s extremely unlikely that the text boxes will contain a valid integer immediately when the form is created - which is where you re getting the integer values   It would make much more sense to update a and b in the button click events  in the same way that you are in the constructor    Also  check out the Int TryParse method - it s much easier to use if the string might not actually contain an integer - it doesn t throw an exception so it s easier to recover from

User · Answer

You have not mentioned if your textbox have values in design time or now  When form initializes text box may not hae value if you have not put it in textbox when during form design  you can put int value in form design by setting text property in desgin and this should work

User · Answer

I ran into this exact exception  except it had nothing to do with parsing numerical inputs   So this isn t an answer to the OP s question  but I think it s acceptable to share the knowledge   I d declared a string and was formatting it for use with JQTree which requires curly braces        You have to use doubled curly braces for it to be accepted as a properly formatted string   string measurements   string empty  measurements    string Format          label   Measurement Name   0            children                  label   Measured Value   1                    label   Min   2                    label   Max   3                    label   Measured String   4                    label   Expected String   5                              drv  MeasurementName      null    NULL    drv  MeasurementName        drv  MeasuredValue      null    NULL    drv  MeasuredValue        drv  Min      null    NULL    drv  Min        drv  Max      null    NULL    drv  Max        drv  MeasuredString      null    NULL    drv  MeasuredString        drv  ExpectedString      null    NULL    drv  ExpectedString       Hopefully this will help other folks who find this question but aren t parsing numerical data

User · Answer

I had a similar problem that I solved with the following technique   The exception was thrown at the following line of code  see the text decorated with    below    static void Main string   args                 double number   0          string numberStr   string Format   0 C2    100              number   Double Parse numberStr              Console WriteLine  The number is  0    number           After a bit of investigating  I realized that the problem was that the formatted string included a dollar sign     that the Parse TryParse methods cannot resolve  i e  - strip off   So using the Remove      method of the string object I changed the line to   number   Double Parse numberStr Remove 0  1       Remove the     from the number   At that point the Parse      method worked as expected

User · Answer

whenever i try to compile the code it says    Input string was not in a correct format        This error won t come on compiling    Now the error comese because you are trying to parse an invalid string to integer  To do it in a safe manner  you should do it like this  int questionID  if int TryParse vTwoOrMoreOptions SelectedItems 0  Text ToString   out questionID       success code   else      failure code

User · Answer

If you are not validating explicitly for numbers in the text field  in any case its better to use  int result 0  if int TryParse textBox1 Text out result     Now if the result is success then you can proceed with your calculations

User · Answer

It looks like some space include in the text  Use      lvTwoOrMoreOptions SelectedItems 0  Text ToString   Trim     and convert to int32   hope this code will solve you  From comments  if your ListView is in report mode  i e  it looks like a grid  then you will need the SubItems property  lvTwoOrMoreOptions SelectedItems gets you each items in the list view - SubItems gets you the columns  So lvTwoOrMoreOptions SelectedItems 0  SubItems 0  is the first column value

User · Answer

In my case I forgot to put double curly brace to escape    myobject

User · Answer

You might be trying to access a control inside a control  maybe a GridView or DetailsView   Try using something like this   empsalary   Convert ToInt32   TextBox DetailsView1 Rows 1  Cells 1  Controls 0   Text

[c#] "Input string was not in a correct format."

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