Question

Basically I have a list:

 List<Decimal> SortOrders = new List<Decimal>();

And a DataRow.
I wan to compare whether the list contains an item from a control.
But I got an exception,

cannot convert from “Object ” to “decimal

DataRow dr = dataSetSomething.Tables[0].NewRow();
...
dr["SortOrder"] = Convert.ToDecimal(numericOrder.Value);// works fine here
if (SortOrders.Contains(dr["SortOrder"]))// exception here, Why?
{
}

Thanks for help.

Answer 1

The type of dr["SortOrder"] is Object.

Any type in .NET is an object (as all types inherit from Object, directly or through the inheritance chain), so assigning a decimal to an object is fine.

The opposite is not true – not all objects are decimal.

You need to cast in order to get the expected behaviour:

 if (SortOrders.Contains((decimal)dr["SortOrder"]))

(which will throw an exception if the underlying type is not a decimal).