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Converting a List to a DataTable

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4.98/5 (26 votes)

Jul 16, 2011

CPOL
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I wrote this because I was interested in a Q&A question which asked for exactly that. Since I quite often use DataTables to transfer data, and to display it for debugging I knocked up an extension method to do it.

Then I realized that arrays implement the IList interface... Hmm. So now, I have an Extension Method that converts any List or array based data into a DataTable. For debugging, that's pretty useful... So, here it is, for posterity:
    public static class ExtensionMethods
        {
        /// <summary>
        /// Converts a List to a datatable
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="data"></param>
        /// <returns></returns>
        public static DataTable ToDataTable<T>(this IList<T> data)
            {
            PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
            DataTable dt = new DataTable();
            for (int i = 0; i < properties.Count; i++)
                {
                PropertyDescriptor property = properties[i];
                dt.Columns.Add(property.Name, property.PropertyType);
                }
            object[] values = new object[properties.Count];
            foreach (T item in data)
                {
                for (int i = 0; i < values.Length; i++)
                    {
                    values[i] = properties[i].GetValue(item);
                    }
                dt.Rows.Add(values);
                }
            return dt;
            }
        }
Public NotInheritable Class ExtensionMethods
    ''' <summary>
    ''' Converts a List to a datatable
    ''' </summary>
    ''' <typeparam name="T"></typeparam>
    ''' <param name="data"></param>
    ''' <returns></returns>
    <System.Runtime.CompilerServices.Extension> _
    Public Shared Function ToDataTable(Of T)(data As IList(Of T)) As DataTable
        Dim properties As PropertyDescriptorCollection = TypeDescriptor.GetProperties(GetType(T))
        Dim dt As New DataTable()
        For i As Integer = 0 To properties.Count - 1
            Dim [property] As PropertyDescriptor = properties(i)
            dt.Columns.Add([property].Name, [property].PropertyType)
        Next
        Dim values As Object() = New Object(properties.Count - 1) {}
        For Each item As T In data
            For i As Integer = 0 To values.Length - 1
                values(i) = properties(i).GetValue(item)
            Next
            dt.Rows.Add(values)
        Next
        Return dt
    End Function
End Class