本文整理匯總了VB.NET中System.Data.DataSet.GetChanges方法的典型用法代碼示例。如果您正苦於以下問題:VB.NET DataSet.GetChanges方法的具體用法?VB.NET DataSet.GetChanges怎麽用?VB.NET DataSet.GetChanges使用的例子?那麽, 這裏精選的方法代碼示例或許可以為您提供幫助。您也可以進一步了解該方法所在類System.Data.DataSet
的用法示例。
在下文中一共展示了DataSet.GetChanges方法的2個代碼示例,這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚,您的評價將有助於係統推薦出更棒的VB.NET代碼示例。
示例1: DemonstrateMerge
Private Sub DemonstrateMerge()
' Create a DataSet with one table, two columns,
' and three rows.
Dim dataSet As New DataSet("dataSet")
Dim table As New DataTable("Items")
Dim idColumn As New DataColumn("id", _
Type.GetType("System.Int32"), "")
idColumn.AutoIncrement = True
Dim itemColumn As New DataColumn("Item", _
Type.GetType("System.Int32"), "")
' Create DataColumn array to set primary key.
Dim keyColumn(0) As DataColumn
Dim row As DataRow
' Create variable for temporary DataSet.
Dim changesDataSet As DataSet
' Add RowChanged event handler for the table.
AddHandler table.RowChanged, AddressOf Row_Changed
dataSet.Tables.Add(table)
table.Columns.Add(idColumn)
table.Columns.Add(itemColumn)
' Set primary key column.
keyColumn(0) = idColumn
table.PrimaryKey = keyColumn
' Add ten rows.
Dim i As Integer
For i = 0 To 9
row = table.NewRow()
row("Item") = i
table.Rows.Add(row)
Next i
' Accept changes.
dataSet.AcceptChanges()
PrintValues(dataSet, "Original values")
' Change row values.
table.Rows(0)("Item") = 50
table.Rows(1)("Item") = 111
' Add one row.
row = table.NewRow()
row("Item") = 74
table.Rows.Add(row)
' Insert code for error checking. Set one row in error.
table.Rows(1).RowError = "over 100"
PrintValues(dataSet, "Modified and New Values")
' If the table has changes or errors, create a subset DataSet.
If dataSet.HasChanges(DataRowState.Modified Or DataRowState.Added) _
And dataSet.HasErrors Then
' Use GetChanges to extract subset.
changesDataSet = dataSet.GetChanges( _
DataRowState.Modified Or DataRowState.Added)
PrintValues(changesDataSet, "Subset values")
' Insert code to reconcile errors. In this case, reject changes.
Dim changesTable As DataTable
For Each changesTable In changesDataSet.Tables
If changesTable.HasErrors Then
Dim changesRow As DataRow
For Each changesRow In changesTable.Rows
'Console.WriteLine(changesRow["Item"]);
If CInt(changesRow("Item", _
DataRowVersion.Current)) > 100 Then
changesRow.RejectChanges()
changesRow.ClearErrors()
End If
Next changesRow
End If
Next changesTable
' Add a column to the changesDataSet.
changesDataSet.Tables("Items").Columns.Add( _
New DataColumn("newColumn"))
PrintValues(changesDataSet, "Reconciled subset values")
' Merge changes back to first DataSet.
dataSet.Merge(changesDataSet, False, _
System.Data.MissingSchemaAction.Add)
End If
PrintValues(dataSet, "Merged Values")
End Sub
Private Sub Row_Changed(sender As Object, e As DataRowChangeEventArgs)
Console.WriteLine("Row Changed " + e.Action.ToString() _
+ ControlChars.Tab + e.Row.ItemArray(0).ToString())
End Sub
Private Sub PrintValues(dataSet As DataSet, label As String)
Console.WriteLine(label + ControlChars.Cr)
Dim table As DataTable
For Each table In dataSet.Tables
Console.WriteLine("TableName: " + table.TableName)
Dim row As DataRow
For Each row In table.Rows
Dim column As DataColumn
For Each column In table.Columns
Console.Write(ControlChars.Tab & " " _
& row(column).ToString())
Next column
Console.WriteLine()
Next row
Next table
End Sub
示例2: UpdateDataSet
Private Sub UpdateDataSet(ByVal dataSet As DataSet)
' Check for changes with the HasChanges method first.
If Not dataSet.HasChanges(DataRowState.Modified) Then
Exit Sub
End If
' Create temporary DataSet variable and
' GetChanges for modified rows only.
Dim tempDataSet As DataSet = _
dataSet.GetChanges(DataRowState.Modified)
' Check the DataSet for errors.
If tempDataSet.HasErrors Then
' Insert code to resolve errors.
End If
' After fixing errors, update the data source with
' the DataAdapter used to create the DataSet.
adapter.Update(tempDataSet)
End Sub