How to modify an extension method to include/exclude specific columns in a DataTable conversion in C#?

I’ve had an extension method that transforms an IEnumerable<T> into a DataTable. It currently processes all public instance properties of type T and adds them as columns to the DataTable

`public static DataTable ToDataTable<T>(this IEnumerable<T> items)
{
    var dataTable = new DataTable("Table");
    var itemType = typeof(T);
    var props = itemType.GetProperties(BindingFlags.Public | BindingFlags.Instance);
    var dateTimeProperties = props.Where(p => p.PropertyType == typeof(DateTime)).ToList();

    // Add all properties as columns
    foreach (var prop in props)
    {
        dataTable.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
    }

    // Populate the rows
    foreach (var item in items)
    {
        var values = props.Select(prop =>
        {
            var value = prop.GetValue(item, null);
            // Handle DateTime formatting
            if (dateTimeProperties.Contains(prop))
            {
                value = ((DateTime)value!).ToString("dd-MMM-yyyy");
            }
            return value;
        }).ToArray();

        dataTable.Rows.Add(values);
    }

    return dataTable;
}`

I’d like to extend this method to allow selective inclusion or exclusion of columns based on the user’s input. I want to introduce two parameters.

columnNames: an optional list of column names to filter by.
includeColumns: a boolean that indicates whether to include (true) or exclude (false) the columns in columnNames.

public static DataTable ToDataTable<T>(this IEnumerable<T> items, string[] columnNames, bool includ = true)

>Solution :

var filteredProps = includeColumns ? props.Where(p => columnNames == null || columnNames.Contains(p.Name)) : props.Where(p => columnNames == null || !columnNames.Contains(p.Name));
var propertyInfos = filteredProps.ToList();
//In Variable `propertyInfos` u will have now all the Filtered Properties.
foreach (var prop in propertyInfos)
{
    dataTable.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
}

Method Signature:

public static DataTable ToDataTable<T>(this IEnumerable<T> items, IEnumerable<string> columnNames, bool includeColumns = true)