How to get desired output using C# datatable

Question

Ok I am changing entire question. I want to generate n*2 rows datatable i.e if primary datatable contains 3 rows , newly created datatable will contain 6 rows (1 row is for True option and 1 row for False option.)

so lets say I have a primary/main table as follows

question_text|right_option
-------------|------------
Question  1  |  True
-------------|------------
Question  2  |  False   
-------------|------------
Question 3   |  True

So question 1's right option is true,question 2's right option is False and so on..

Now based on this table I want to create a table as follows..

question_text|option_text * | right_option
-------------|--------------|-------------
question 1   |  True        | True
-------------|--------------|-------------
question 1   | False        |  True
-------------|--------------|-------------
question 2   |  True        |  False
-------------|--------------|-------------
question 2   |  False       |  False

here option_text is hard coded column whose value will be True and False only..

table (nx2) goes as follows...

DataTable dtTrueFalse = Import_To_Grid(FilePath, Extension, "Yes"); // primary table where only right option exist
    for (int i = 0; i < dtTrueFalse.Rows.Count * 2; i++)
    {
         DataRow dr;
         if (i % 2 == 0)
         {
             dr = dtOptions.NewRow();
             dr["Option_Text"] = "True";
          }
          else
          {
             dr = dtOptions.NewRow();
             dr["Option_Text"] = "False";
          }
           dtOptions.Rows.Add(dr);
    }

after creating I will have this ..

question_text|option_text   | right_option
-------------|--------------|-------------
question 1   |  True        | 
-------------|--------------|-------------
question 1   | False        |  
-------------|--------------|-------------
question 2   |  True        |  
-------------|--------------|-------------
question 2   |  False       |

Now, I wanna know how to insert value into right_option column?Please help me out..

dsdel · Accepted Answer · 2018-03-22 07:17:23Z

1

You did not post the creation of your data table...

I assume, that there is not yet any column 'right_option' - so you would need to add it at first by using

dtTrueFalse.Columns.Add("right_option");

Afterwards you can access this column in each row like you did with 'option_text':

dr["right_option"] = "False";

EDIT

Based on your comments, is the following code what you really need?

            // build source datatable
            DataTable dtTrueFalse = new DataTable(); 
            dtTrueFalse.Columns.AddRange(new[] { new DataColumn("question_text"), new DataColumn("Right_Option") });

            // add dummy data
            var dummyRow = dtTrueFalse.NewRow();
            dummyRow["question_text"] = "qst 1";
            dummyRow["Right_Option"] = "False";
            dtTrueFalse.Rows.Add(dummyRow);

            // build final datattable
            DataTable dtOptions = new DataTable();
            dtOptions.Columns.AddRange(new[] {new DataColumn("question_text"), new DataColumn("Right_Option"), new DataColumn("Option_Text")});

            // add rows....
            foreach (DataRow row in dtTrueFalse.Rows)
            {
                var newRowTrue = dtOptions.NewRow();
                newRowTrue["question_text"] = row["question_text"];
                newRowTrue["Right_Option"] = row["Right_Option"];
                newRowTrue["Option_Text"] = "True";
                dtOptions.Rows.Add(newRowTrue);

                var newRowFalse = dtOptions.NewRow();
                newRowFalse["question_text"] = row["question_text"];
                newRowFalse["Right_Option"] = row["Right_Option"];
                newRowFalse["Option_Text"] = "False";
                dtOptions.Rows.Add(newRowFalse);
            }

edited Mar 22, 2018 at 7:17

answered Mar 22, 2018 at 6:45

dsdel

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6 Comments

Babai Over a year ago

DataTable dtOptions = new DataTable(); dtOptions.Columns.AddRange(new []{new DataColumn("Right_Option"),new DataColumn("Option_Text")});

Babai Over a year ago

I have not posted that because I have already created n x 2 table

Babai Over a year ago

I am doing it because I can easily pass entire table to db using tvp.

dsdel Over a year ago

and with using dr["right_option"] you cannot access the columns? Checked in debugging if the datatable has got the column? Not that you mixed up the datatables

Babai Over a year ago

I can acess , but I want algo say 0,1 row of newly created table mapped to 0 th row of primary table, 2,3 row of newly created table mapped to 1 st row of primary table and so on..

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