Convert IEnumerable to DataTable?

[Ronald S. Cook]

Does anyone know how to convert an object of type IEnumerable to a
DataTable?

Thanks,
Ron

 

[Alberto Poblacion]

Does anyone know how to convert an object of type IEnumerable to a
DataTable?

There is no automatic way. You will have to iterate on the contents of the
IEnumerable in a loop, and then add each object returned by the enumerator
to a new DataRow in the DataTable. Of course, this raises the question of
"what kind of table and which columns should it have". If you want to do it
in a general way that will be valid for any IEnumerable, you will have to
use Reflection on the returned objects to find out their properties (or
fields) and then create a datatable with columns of the same type, and then
use Reflection again to get the values and add them to the columns of each
row.

private DataTable ObtainDataTableFromIEnumerable(IEnumerable ien)
{
DataTable dt = new DataTable();
foreach (object obj in ien)
{
Type t = obj.GetType();
PropertyInfo[] pis = t.GetProperties();
if (dt.Columns.Count == 0)
{
foreach (PropertyInfo pi in pis)
{
dt.Columns.Add(pi.Name, pi.PropertyType);
}
}
DataRow dr = dt.NewRow();
foreach (PropertyInfo pi in pis)
{
object value = pi.GetValue(obj, null);
dr[pi.Name] = value;
}
dt.Rows.Add(dr);
}
return dt;
}

 

[Ronald S. Cook]

Thanks. To then update the database, I guess you can't somehow iterate over
the DataTable and recreate the IEnumerable, huh? How then would yoiu update
the database?

Thanks for the help.

Does anyone know how to convert an object of type IEnumerable to a
DataTable?

There is no automatic way. You will have to iterate on the contents of the
IEnumerable in a loop, and then add each object returned by the enumerator
to a new DataRow in the DataTable. Of course, this raises the question of
"what kind of table and which columns should it have". If you want to do
it in a general way that will be valid for any IEnumerable, you will have
to use Reflection on the returned objects to find out their properties (or
fields) and then create a datatable with columns of the same type, and
then use Reflection again to get the values and add them to the columns of
each row.

private DataTable ObtainDataTableFromIEnumerable(IEnumerable ien)
{
DataTable dt = new DataTable();
foreach (object obj in ien)
{
Type t = obj.GetType();
PropertyInfo[] pis = t.GetProperties();
if (dt.Columns.Count == 0)
{
foreach (PropertyInfo pi in pis)
{
dt.Columns.Add(pi.Name, pi.PropertyType);
}
}
DataRow dr = dt.NewRow();
foreach (PropertyInfo pi in pis)
{
object value = pi.GetValue(obj, null);
dr[pi.Name] = value;
}
dt.Rows.Add(dr);
}
return dt;
}

 

[Lasse Vågsæther Karlsen]

Thanks. To then update the database, I guess you can't somehow iterate
over the DataTable and recreate the IEnumerable, huh? How then would
yoiu update the database?

Thanks for the help.

Does anyone know how to convert an object of type IEnumerable to a
DataTable?

There is no automatic way. You will have to iterate on the contents of
the IEnumerable in a loop, and then add each object returned by the
enumerator to a new DataRow in the DataTable. Of course, this raises
the question of "what kind of table and which columns should it have".
If you want to do it in a general way that will be valid for any
IEnumerable, you will have to use Reflection on the returned objects
to find out their properties (or fields) and then create a datatable
with columns of the same type, and then use Reflection again to get
the values and add them to the columns of each row.

private DataTable ObtainDataTableFromIEnumerable(IEnumerable ien)
{
DataTable dt = new DataTable();
foreach (object obj in ien)
{
Type t = obj.GetType();
PropertyInfo[] pis = t.GetProperties();
if (dt.Columns.Count == 0)
{
foreach (PropertyInfo pi in pis)
{
dt.Columns.Add(pi.Name, pi.PropertyType);
}
}
DataRow dr = dt.NewRow();
foreach (PropertyInfo pi in pis)
{
object value = pi.GetValue(obj, null);
dr[pi.Name] = value;
}
dt.Rows.Add(dr);
}
return dt;
}

Well, an IEnumerable isn't normally updateable in any way and you would
need a lot more data about where the IEnumerable came from before you
can start pushing updates back to the source.

If you need to work with generic IEnumerable objects, then I dare say
this will not be possible, however if you can limit yourself to certain
types of IEnumerable, like LINQ results and similar, then I think you
can get back the original source. Unfortunately I haven't used LINQ to
SQL a lot yet so I don't really know.