Dim oDataRow As DataRow Dim oDataColumn As DataColumn Dim aPrimaryKey(0) As DataColumn oDS = New DataSet 'Create a new DataTable oect oEmployeeDT = New DataTable 'Add an event handler for column data changes AddHandler oEmployeeDT.ColumnChanged, _ New DataColumnChangeEventHandler(AddressOf _ ColumnChanged) 'Create primary key (PK) col and add it to the columns 'collection. Set init value to 1, increment as needed. oDataColumn = New DataColumn oDataColumn.ColumnName = "ID" oDataColumn.DataType = _ System.Type.GetType("System.Int32") oDataColumn.AutoIncrement = True oDataColumn.AutoIncrementSeed = 1 oEmployeeDT.Columns.Add (oDataColumn) 'PK property receives array of DataColumn objects in 'case you have multi-col index. I prefer an ID column. aPrimaryKey(0) = oDataColumn oEmployeeDT.PrimaryKey = aPrimaryKey 'Create the individual data columns a�| oDataColumn = New DataColumn oDataColumn.ColumnName = "Salary" oDataColumn.DataType = _ System.Type.GetType("System.Decimal") oEmployeeDT.Columns.Add (oDataColumn) 'Here we use DataColumn's Expression property to show 'what a 28% tax on the salary will amount to. oDataColumn = New DataColumn oDataColumn.ColumnName = "IncomeTax" oDataColumn.DataType = _ System.Type.GetType("System.Decimal") oDataColumn.Expression = "Salary * .28" oEmployeeDT.Columns.Add (oDataColumn) oDataColumn = New DataColumn oDataColumn.ColumnName = "HireDate" oDataColumn.DataType = _ System.Type.GetType("System.DateTime") oEmployeeDT.Columns.Add (oDataColumn) 'This col receives the value calc'd by event handler oDataColumn = New DataColumn oDataColumn.ColumnName = "DaysSinceHire" oDataColumn.DataType = _ System.Type.GetType("System.Int16") oEmployeeDT.Columns.Add (oDataColumn) 'Once the columns are added, add sample data oDataRow = oEmployeeDT.NewRow() oDataRow("LastName") = "Washington" oDataRow("FirstName") = "George" oDataRow("Salary") = 45000 oDataRow("IncomeTax") = True oDataRow("HireDate") = "4/12/1981" oEmployeeDT.Rows.Add (oDataRow) a�| 'Commit new data to the DataTable object and set 'RowState values of each row to Unchanged oEmployeeDT.AcceptChanges() 'Let's show the user DataGrid1.DataSource = oEmployeeDT
Sub ColumnChanged(ByVal sender As Object, _ ByVal e As DataColumnChangeEventArgs) If e.Column.ColumnName = "HireDate" Then e.Row("DaysSinceHire") = _ DateDiff(DateInterval.Day,
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