' Put the next line into the Declarations section.
private dataSet As DataSet
Private Sub MakeDataTables()
' Run all of the functions.
MakeParentTable()
MakeChildTable()
MakeDataRelation()
BindToDataGrid()
End Sub
Private Sub MakeParentTable()
' Create a new DataTable.
Dim table As DataTable = new DataTable("ParentTable")
' Declare variables for DataColumn and DataRow objects.
Dim column As DataColumn
Dim row As DataRow
' Create new DataColumn, set DataType, ColumnName
' and add to DataTable.
column = New DataColumn()
column.DataType = System.Type.GetType("System.Int32")
column.ColumnName = "id"
column.ReadOnly = True
column.Unique = True
' Add the Column to the DataColumnCollection.
table.Columns.Add(column)
' Create second column.
column = New DataColumn()
column.DataType = System.Type.GetType("System.String")
column.ColumnName = "ParentItem"
column.AutoIncrement = False
column.Caption = "ParentItem"
column.ReadOnly = False
column.Unique = False
' Add the column to the table.
table.Columns.Add(column)
' Make the ID column the primary key column.
Dim PrimaryKeyColumns(0) As DataColumn
PrimaryKeyColumns(0)= table.Columns("id")
table.PrimaryKey = PrimaryKeyColumns
' Instantiate the DataSet variable.
dataSet = New DataSet()
' Add the new DataTable to the DataSet.
dataSet.Tables.Add(table)
' Create three new DataRow objects and add
' them to the DataTable
Dim i As Integer
For i = 0 to 2
row = table.NewRow()
row("id") = i
row("ParentItem") = "ParentItem " + i.ToString()
table.Rows.Add(row)
Next i
End Sub
Private Sub MakeChildTable()
' Create a new DataTable.
Dim table As DataTable = New DataTable("childTable")
Dim column As DataColumn
Dim row As DataRow
' Create first column and add to the DataTable.
column = New DataColumn()
column.DataType= System.Type.GetType("System.Int32")
column.ColumnName = "ChildID"
column.AutoIncrement = True
column.Caption = "ID"
column.ReadOnly = True
column.Unique = True
' Add the column to the DataColumnCollection.
table.Columns.Add(column)
' Create second column.
column = New DataColumn()
column.DataType= System.Type.GetType("System.String")
column.ColumnName = "ChildItem"
column.AutoIncrement = False
column.Caption = "ChildItem"
column.ReadOnly = False
column.Unique = False
table.Columns.Add(column)
' Create third column.
column = New DataColumn()
column.DataType= System.Type.GetType("System.Int32")
column.ColumnName = "ParentID"
column.AutoIncrement = False
column.Caption = "ParentID"
column.ReadOnly = False
column.Unique = False
table.Columns.Add(column)
dataSet.Tables.Add(table)
' Create three sets of DataRow objects, five rows each,
' and add to DataTable.
Dim i As Integer
For i = 0 to 4
row = table.NewRow()
row("childID") = i
row("ChildItem") = "Item " + i.ToString()
row("ParentID") = 0
table.Rows.Add(row)
Next i
For i = 0 to 4
row = table.NewRow()
row("childID") = i + 5
row("ChildItem") = "Item " + i.ToString()
row("ParentID") = 1
table.Rows.Add(row)
Next i
For i = 0 to 4
row = table.NewRow()
row("childID") = i + 10
row("ChildItem") = "Item " + i.ToString()
row("ParentID") = 2
table.Rows.Add(row)
Next i
End Sub
Private Sub MakeDataRelation()
' DataRelation requires two DataColumn
' (parent and child) and a name.
Dim parentColumn As DataColumn = _
dataSet.Tables("ParentTable").Columns("id")
Dim childColumn As DataColumn = _
dataSet.Tables("ChildTable").Columns("ParentID")
Dim relation As DataRelation = new _
DataRelation("parent2Child", parentColumn, childColumn)
dataSet.Tables("ChildTable").ParentRelations.Add(relation)
End Sub
Private Sub BindToDataGrid()
' Instruct the DataGrid to bind to the DataSet, with the
' ParentTable as the topmost DataTable.
DataGrid1.SetDataBinding(dataSet,"ParentTable")
End Sub