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| Option Explicit On | |
| Option Strict On | |
| Imports System | |
| Imports System.Data | |
| Imports System.Data.SqlClient | |
| Imports System.Data.SqlTypes | |
| Module Module1 | |
| Sub Main() | |
| WorkWithSqlNulls() | |
| Console.ReadLine() | |
| End Sub | |
| ' <Snippet1> | |
| Private Sub WorkWithSqlNulls() | |
| Dim table As New DataTable() | |
| ' Specify the SqlType for each column. | |
| Dim idColumn As DataColumn = _ | |
| table.Columns.Add("ID", GetType(SqlInt32)) | |
| Dim descColumn As DataColumn = _ | |
| table.Columns.Add("Description", GetType(SqlString)) | |
| ' Add some data. | |
| Dim row As DataRow = table.NewRow() | |
| row("ID") = 123 | |
| row("Description") = "Side Mirror" | |
| table.Rows.Add(row) | |
| ' Add null values. | |
| row = table.NewRow() | |
| row("ID") = SqlInt32.Null | |
| row("Description") = SqlString.Null | |
| table.Rows.Add(row) | |
| ' Initialize variables to use when | |
| ' extracting the data. | |
| Dim isColumnNull As SqlBoolean = False | |
| Dim idValue As SqlInt32 = SqlInt32.Zero | |
| Dim descriptionValue As SqlString = SqlString.Null | |
| ' Iterate through the DataTable and display the values. | |
| For Each row In table.Rows | |
| ' Assign values to variables. Note that you | |
| ' do not have to test for null values. | |
| idValue = CType(row("ID"), SqlInt32) | |
| descriptionValue = CType(row("Description"), SqlString) | |
| ' Test for null value with ID column | |
| isColumnNull = idValue.IsNull | |
| ' Display variable values in console window. | |
| Console.Write("isColumnNull={0}, ID={1}, Description={2}", _ | |
| isColumnNull, idValue, descriptionValue) | |
| Console.WriteLine() | |
| Next row | |
| End Sub | |
| ' </Snippet1> | |
| End Module | |