How to replace datatable headers with arraylist items in C#

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Hi,
I found this bit challenging.I need to update my datatable headers dynamically for that i have an arraylist of updated headers

var distinctArray = newcolumnsList.ToArray();

I have datatable dTable with old headers and values.I want to replace dTable headers with

distinctArray values.How can do this? (5 old headers remove and add 5 new headers in distinctArray,dynamically )

What I have tried:

var distinctArray = newcolumnsList.ToArray(); // array having new headings.

foreach (string item in distinctArray)
{
dTable[0].Rows.Add(item);
}
return dTable;
}

Posted 15-Sep-20 18:25pm

Manidas Payyoli

Updated 15-Sep-20 20:14pm

TheRealSteveJudge

v4

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TheRealSteveJudge · Accepted Answer · 2020-09-15T20:12:00

Here you are an example how to do it.

C#

using System.Collections.Generic;
using System.Data;

namespace DataTableTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var dt = new DataTable();

            var dataColumns = new List<DataColumn>
            {
                new DataColumn("A"),
                new DataColumn("B"),
                new DataColumn("C"),
                new DataColumn("D"),
                new DataColumn("E")
            }.ToArray();

            dt.Columns.AddRange(dataColumns);

            dt.Rows.Add(1, 2, 3, 4, 5);

            var newDataColumns = new List<DataColumn>
            {
                new DataColumn("F"),
                new DataColumn("G"),
                new DataColumn("H"),
                new DataColumn("I"),
                new DataColumn("J")
            }.ToArray();

            dt.Columns.Clear();

            dt.Columns.AddRange(newDataColumns);
        }
    }
}

You cannot replace DataColumns directly.
You must first remove the old DataColumns by using the Clear method.

C#

dt.Columns.Clear();

Then you can add a new DataColumn array.

C#

dt.Columns.AddRange(newDataColumns);

A good idea might be to use a debugger to see what is happening after each line of code.
Moreover it is recommended to read this article:
A Practical Guide to .NET DataTables, DataSets and DataGrids - Part 1[^]