Categories: Dotnet/.NET - C#Programming

Convert List<T>/IEnumerable to DataTable/DataView

Greetings visitor from the year 2025! You can get the source code for this from my Github repo here. Thanks for visiting.

Here’s a method to convert a generic List<T> to a DataTable. This can be used with ObjectDataSource so you get automatic sorting, etc.

using statement: using System.Reflection;
...

/// <summary>
/// Convert a List{T} to a DataTable.
/// </summary>
public DataTable ToDataTable<T>(List<T> items)
{
    var tb = new DataTable(typeof (T).Name);

    PropertyInfo[] props = typeof (T).GetProperties(BindingFlags.Public | BindingFlags.Instance);

    foreach (PropertyInfo prop in props)
    {
        Type t = GetCoreType(prop.PropertyType);
        tb.Columns.Add(prop.Name, t);
    }

    foreach (T item in items)
    {
        var values = new object[props.Length];

        for (int i = 0; i < props.Length; i++)
        {
            values[i] = props[i].GetValue(item, null);
        }

        tb.Rows.Add(values);
    }

    return tb;
}

/// <summary>
/// Determine of specified type is nullable
/// </summary>
public static bool IsNullable(Type t)
{
    return !t.IsValueType || (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));
}

/// <summary>
/// Return underlying type if type is Nullable otherwise return the type
/// </summary>
public static Type GetCoreType(Type t)
{
    if (t != null && IsNullable(t))
    {
        if (!t.IsValueType)
        {
            return t;
        }
        else
        {
            return Nullable.GetUnderlyingType(t);
        }
    }
    else
    {
        return t;
    }
}

Chinh Do

I occasionally blog about programming (.NET, Node.js, Java, PowerShell, React, Angular, JavaScript, etc), gadgets, etc. Follow me on Twitter for tips on those same topics. You can also find me on GitHub. See About for more info.

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View Comments

Allen says:

February 8, 2011 at 4:36 pm

Pretty nice! If you want to compare notes to Microsoft's version of the same thing for use as an extension method, take a look to the following MSDN link:

http://msdn.microsoft.com/en-us/library/bb669096(v=vs.90).aspx#4
- Chinh Do says:
  
  February 8, 2011 at 5:01 pm
  
  Thanks for the link Allen. Will check it out. Chinh
Mark J says:

March 4, 2011 at 5:24 am

Very nice code - came in handy at just the right time!
Daniel says:

March 15, 2011 at 6:40 pm

Dude!!! you are lifesaver.
I've been trying to get this #@#$ thing to work for more than 5 hours.
Thanks a lot!
- Chinh Do says:
  
  April 7, 2011 at 9:32 am
  
  Glad to hear that.
Saif says:

September 27, 2011 at 7:58 am

This is not working when I join two table with all columns selected.

var productsQuery = (from p in db.Products
join c in db.Categories
on p.Category_Id equals c.Category_Id
where p.Vendor_Code == VendorCode
select new { p,c });

DataTable dt = LinqToDataTable.ToDataTable(productsQuery.ToList());

Please suggest what to do?
Saeed Neamati says:

May 13, 2012 at 2:25 am

That's why I love reflection. Understanding what goes on inside an unknown object (late-binding) is one of the most powerful programming concepts. Thanks for this nice code snippet.
Chinh Do says:

May 13, 2012 at 6:27 am

Thanks, Saeed. Glad you found this.
Zach says:

August 2, 2012 at 2:06 pm

Thanks for the code...I would have lost hours and hours trying to figure this out myself.

You're awesome!
- Chinh Do says:
  
  August 2, 2012 at 2:08 pm
  
  Zach: Thanks for leaving me a note. That's great.
http://tinyurl.com/unidstack29328 says:

January 26, 2013 at 11:47 pm

“Convert List/IEnumerable to DataTable/DataView � Chinh Doâ was in fact a wonderful post and also I really was in fact really happy to discover the blog post.

I appreciate it,Hye
Developer says:

May 9, 2019 at 11:26 pm

Good!
DMITRIY SABITOV says:

November 23, 2024 at 8:32 am

Dear Chinh Do!

I suggest a slightly revised version of your code. As a result, you can get a datatable from an IEnumerable with values of value type and strings.

public static DataTable ToDataTable(IEnumerable input)
{
DataTable dt = new DataTable(typeof(T).Name);

PropertyInfo[] properties = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);

if (typeof(T).IsValueType || typeof(T) == typeof(System.String))
{
Type t = GetCoreType(typeof(T));
dt.Columns.Add(typeof(T).Name+"C", t);
}
else
{
foreach (PropertyInfo property in properties)
{
Type t = GetCoreType(property.PropertyType);
dt.Columns.Add(property.Name, t);
}
}

foreach (T item in input)
{
if (typeof(T).IsValueType || typeof(T) == typeof(System.String))
{
dt.Rows.Add(item);
}
else
{
object[] values = new object[properties.Length];
for (int i = 0; i < properties.Length; i++)
{
values[i] = properties[i].GetValue(item, null);
}
dt.Rows.Add(values);
}
}
return dt;
}
public static Type GetCoreType(Type t)
{
if (t != null && IsNullable(t))
{
if (!t.IsValueType) { return t; }
else { return Nullable.GetUnderlyingType(t); }
}
else { return t; }
}
public static bool IsNullable(Type t)
{
return !t.IsValueType || (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable));
}