Create a datatable column between two column in C#

Question

I have a Datatable. For example :

private DataTable GetGenericDatatable(){
    DataTable retval = new DataTable();
    retval.Columns.Add("ProtocolNumber");
    retval.Columns.Add("Name");
    retval.Columns.Add("Company");
    retval.Columns.Add("Department");
    retval.Columns.Add("VisitDate");
    retval.Columns.Add("DispatchTargetName");
    retval.Columns.Add("DayOffCount");
    // add data ...
    return retval;
}

I want to insert some columns between "Department" and "VisitDate" columns dynamically even the datatable is full with data.

We can do this by creating new datatable, creating the columns again etc. but it is a dirty solution. Any idea for a clear solution?

Please look at this post. http://stackoverflow.com/questions/12937516/datatable-column-reorder — Raghu, Aug 26 '14 at 08:37
@Raghu Yes, it looks good but sometimes inserted columns count may be over 30+, and rewrite 30+ columns again sounds not good. — obayhan, Aug 26 '14 at 10:04

score 1 · Answer 1 · answered Aug 26 '14 at 08:35

1

Add a new DataColumn and use the SetOrdinal method to set its position:

var col = retval.Columns.Add("New Column");
col.SetOrdinal(4);

answered Aug 26 '14 at 08:35

sloth

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Thanks for your effort. 1 Up – obayhan Aug 26 '14 at 10:07

Tim Schmelter · Accepted Answer · 2014-08-26T08:41:17.970

You can assign a DefaultValue to the DataColumm:

DataTable tbl = GetGenericDatatable();
tbl.Columns.Add(new DataColumn("Col1") { DefaultValue="def. value"});
tbl.Columns.Add(new DataColumn("Col2", typeof(DateTime)) { DefaultValue = DateTime.Now });

This value will be applied to every existing row in the table.

You can use SetOrdinal to set the index of a column. For example:

tbl.Columns["Col1"].SetOrdinal(tbl.Columns.IndexOf("VisitDate"));
tbl.Columns["Col2"].SetOrdinal(tbl.Columns.IndexOf("VisitDate"));

Now the new columns are between Department and VisitDate, Col1 before Col2.

score 1 · Answer 3 · answered Aug 26 '14 at 10:47

You could use this Extension:

namespace System
{
    public static class Extensions
    {
        public static void AddColumnAfter(this DataColumnCollection columnCollection, string afterWhichColumn, DataColumn column)
        {
            var columnIndex = columnCollection.IndexOf(afterWhichColumn);
            columnCollection.Add(column);
            columnCollection[column.ColumnName].SetOrdinal(columnIndex + 1);
        }
    }
}

Example:

 DataTable table = new DataTable();
 table.Columns.Add("Column 1");
 table.Columns.Add("Column 2");
 table.Columns.Add("Column 3");
 table.Columns.AddColumnAfter("Column 1", new DataColumn("Column 4"));

Create a datatable column between two column in C#

3 Answers3