Tag: Visual Basic Language Value of type 'System.Data.DataTable' cannot be converted to 'System.Collections.Generic.List(Of System.Data.DataTable)' Visual Basic 7 ANSI C double to VB.Net Double via Socket There are actually a couple dozen such structures that, among them, contain almost every basic type. This sample serializes a T:System.Data.DataSet to JSON. Namespace = 'NetFrameWork'; DataTable table = new DataTable; DataColumn idColumn = new.
![]() ![]()
NoteA column of data type Byte requires special treatment in certain cases since, unlike the base.NET Framework data types, it is a reference data type. If a column of data type Byte is used as a, or as a or key for a, any change to the column value must involve assigning the Byte column value to a separately instantiated Byte object. This assignment is required to trigger the update of the internal indexes used by sorting, filtering, and primary key operations. This is illustrated by the following example: byte columnValue = (byte)myDataTable.Rows00;byte newValue = (byte)columnValue.Clone;newValue1 = 2;myDataTable.Rows00 = newValue. NoteAlthough it is possible to define a column as data type other than the base.NET Framework data types and Byte, such a column will be treated as a user-defined type, subject to the following usage restrictions.
![]()
(For more information on user-defined types, see.).The column cannot be part of a or expression.If the column is used as a, or as a or for a, it must be treated as an immutable field; the column data must not be changed once it has been added to the table.Its can be only set to MappingType.Element.The class that implements the column's data type must be must be marked with the, and if necessary implement the or interface.Support for change tracking is limited. To utilize the class' change tracking mechanism, the class that implements the column's data type must either implement the interface, or take over the responsibility for informing the when the column value has been modified, either by calling on the row or by assigning the column value object to a separately instantiated column value object.Applies to See also.
![]() Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
March 2023
Categories |